Subscribe via RSS

486DX266: CMOS Battery and PC Speaker

After building this machine, I am finding that I am losing my BIOS settings each time I pull the plug at the wall. The original motherboard owner/restorer replaced the onboard battery with a coin cell socket, but it seems that the 3v cell I put in there isn't powerful enough to keep the charge!

DSC00010

PC Restorer has a great article on CMOS batteries and the best point to take form their site is that most BIOS' need 3.6-4.5v to keep their memory.

DSC00011

In the picture above, you'll see the 4-pin header for an external battery. Pin 2 is missing. On this motherboard, pin 1 is positive and pins 3 and 4 are ground.

Using a standard 4-pin header plug from Jaycar, I wired up a 4-cell AA battery pack, but only used 3 cells. This required soldering new wires to allow current to flow between only three of the batteries.

DSC00004 DSC00006 DSC00008

With this all soldered, a quick test with the multimeter saw ~4.89v on the pins... which was more than expected, but an acceptable value.

DSC00013

Installation was a breeze and testing proved that my BIOS settings finally held!

PC Speaker

The case I have installed this machine in didn't have a PC Speaker installed by default. Therefore I used the same 4-pin header to rig up an 8ohm speaker from Jaycar. There's no real need to worry about the polarity here as it's just mainly beeps and boops. Who cares which way the diaphragm shifts?

DSC00015 DSC00016 DSC00017

On first boot, the machine-gun noise of RAM counting up was music to my ears!!

Filed under: Retro No Comments
16Mar/170

486DX266: Rebuilding my childhood PC

I've been itching to do this for a while. There've been some nice 486 motherboards coming up on eBay, but I haven't been in the position to get them until now. A Hippo VL+ board appeared and, although it had suffered battery damaged (and been repaired!), it was a bargain for the price. I've always wanted to tinker with the VESA Local Bus and now was my chance. I did have a VLB board back in the day, but hardly knew what it meant.

Base Components

This was to be a completely build-it-yourself project. Each item was individually selected from whatever came on offer via eBay. First up was the motherboard with 4mb of RAM and that all-important exactly-what-I-wanted 486 DX2/66 processor.

DSC00191

DSC00192 DSC00193 DSC00194

DSC00195 DSC00197DSC00198

You can see where the previous owner has repaired a leaking CMOS battery. The wiring has been well-done and is all hot-glue-gunned down. The coin cell slot is in its place, but I seem to still be getting CMOS battery low issues. It could be that the coin cell battery is only 3v when the CMOS needs 3.5v+.

Next up was the VLB controller card. These full-length half-height cards provide two IDE channels, two floppy drives (via one cable), 2 com ports, a game port and a printer port! The HDD activity LED is also attached to this card.

DSC00199

DSC00200 DSC00201 DSC00202

Finally, the all-important video card. I happened across a cheap S3 86C805i VLB card. It has expandable RAM of which I'll try and fill later on.

DSC00204

DSC00205 DSC00207 DSC00209

There are only three slots where these cards fit into. You'll also find that they are named as to their purpose! There are two 'master' slots and a 'slave'. For those playing at home, the 'master' slots allow cards that support bus mastering; where the card will receive direct information rather than data via the CPU, and have it's own processing power on-board. The slave slot is for cards that don't support bus mastering but want the additional bandwidth of the VLB.

DSC00210

A quick trial assembly then took place. Be really careful when doing this on a flat surface! The end plates have tabs that are meant to slot into the case when the board is mounted... when not, they will simply push into your desk/table and pressing further is strongly discouraged!

DSC00213

Housing

I picked up a AUD$1.00 ATX case from eBay. Yes. ATX. It'll never work, you say? I have previously already put a 386 in an ATX case, but that was whilst keeping its old AT power supply and having the power cord hanging out the side. Not very neat. This time around we're going to do things differently.

DSC00314

Meet the case, creepy photo, right? It's full ATX... soft buttons and all. It even has an ATX power supply.

DSC00316

How do we possibly use an ATX supply with an AT motherboard? With an adapter plug! This beauty was found on eBay for the handsome sum of AUD$5.00.

DSC00320

So, simple mounting of the board ensued. Turns out the back plane is riveted into the case; annoying as previous cases I've dealt with usually allow this panel to be removed for easier motherboard mounting. Either way, the motherboard was mounted in and the adapter was hooked to the power supply.

DSC00321

The other end was then slapped onto the board itself. Remember with AT plugs, keep the black wires together!

DSC00323

Great ... so ... now what? The front panel can be rudimentarily hooked up. Reset, Power LED, Turbo LED? and that's it.

DSC00319

The case was stood up, all cables checked and arranged neatly so as to not cause any shorting issues and then a monitor was connected. The power supply was then jump started. This is simple: simple join the 'dangling' green and black wires together.

It worked!

ATX case + power supply without an ATX motherboard

Here's the trick you've been waiting for. The power button on the front of the ATX is momentary. This means that when you press it, power is conducted for only the timespan until you let go. So, if we hooked this up directly to the green/black wires from the power supply, we'd need to hold/tape the button down until we were done with the computer... not very handy.

Because of this, we're going to use a relay to latch the required power supply wires. The basic idea is that we'll put the momentary button on the green and black wires from the power supply and then latch those down when power starts to flow. To do this, we'll use a drive power plug which will supply us with 12v/5v when we've pressed the power button. This power feed will then latch a relay that'll latch the power button. When we let go, the power will continue as the relay will emulate an extended press!

initial-atx-power-hook

So, apologies for the crude diagram, but that's the basic idea above. The relay is a 12v single-pole-double-throw and therefore has power, common, normally-connected and normally-open terminals. Power is used to actually throw the relay and is fed from the 12v drive power. Normally-opened isn't used as we only care about the actuation of the relay. The normally-closed side is therefore put in parallel with the power switch. When the switch is pressed, the relay fires and reinforces the power button.

The best part? It worked perfectly! The machine came on and I played A-Train. The problem? Hitting Reset did as expected... it reset the machine, but I had no way of turning it off without yanking power cables! I originally hoped that reset would trip the drive power and reset the relay; alas it turns out that the 12v stays constant. We therefore have to amend the circuit to allow powering down the machine from the reset button.

reset-atx-power-hook

Here, we've taken the reset switch off the motherboard and used it for an off switch. This means that the machine is power-for-on, reset-for-off. It makes sense... doing an actual reset will just mean hitting reset-and-then-power instead of just reset.

In the above diagram, we've used a second identical relay to interrupt the power supply of the first relay. To do this, we've fed one of the coil power feeds of the first relay through the normally-closed line of the second relay. This means that, when the second relay is not active, the current can flow through it to the first relay. Exactly as we want, as we don't want to do anything until the reset button is pressed.

When the reset button is pressed, it'll actuate the second relay and break the current to the first relay. This will, in turn, break the latch on the power switch and the ATX supply will shut off. Pressing the power switch again will re-latch the power and we'll be up and running again.

Actually building it

I used some crappy veroboard and a spare drive power plug that I had laying around. Hot glue then helped to insulate everything. Note that in my initial sketch, I was trying to be overly-tricky and had the 5v power fed through the other side of a DPDT really. This is redundant and really not needed!

DSC00006

DSC00009 DSC00011 DSC00013

The final product worked perfectly!

Filed under: Retro No Comments
10Mar/170

Compaq Deskpro 386s/20n: RH Linux 5.2

I had tried to load BSD on this thing a while back, but didn't get very far. Recently I found an original boxed-set of RedHat Linux 5.2 and, to my surprise, the system requirements had this machine's specifications as the recommended minimum! I was therefore very happy that I had previously managed to find an 8mb RAM upgrade for this machine.

Installing a big-enough IDE disk

The 40mb Conner that was in there was never going to suffice. I'd previously installed a 256mb 'SSD' disk, but this wouldn't do either. Instead, I'd recently picked up a 1.2g IDE from the flea markets, which won't work straight away with DOS (Use AnyDrive for that), but will work fine in Linux as the bios specifications are bypassed.

DSC00258

RedHat 5.2 comes with 3 installation CDs and a boot disk. I had previously built a PIII-500 and installed RH from these disks, so I knew the software was in working order. It was whilst installing RedHat on that machine that I saw that it may well also work with the 386. Just for fun, I slapped the boot disk in to the 386 and quickly got the LILO boot loader. After a short while I was in the installer, only to hit my first hurdle: the installation obviously needs CD access! The Compaq has a very slim case, so there was no option to install an internal drive. I'd previously used my Microsolutions Backpack Parallel Port drive under DOS on this machine, so I thought I'd give it a go with Linux.

RedHat comes with a bpcd.o driver for this device but I couldn't get it going! I tried all permutations of configuration for the driver (linux bpcd=0x3bc as a LILO boot command and also bp_base=0x3bc during install), but nothing would get the drive to spin up! Booting into DOS, I found the correct address to be 0x3bc... but nothing would make it work.

Turns out I'm not the only one.

Installing over the network

I could choose FTP from the boot disk, but it them asked for a supplementary disk? I only had CDs at this point, so I couldn't continue.

DSC00259

The next best option was NFS and so I started searching for NFS Servers on Windows, as that was the easiest and closest machine available to host the required files. There were three options: FreeNFS, winnfsd and nfsAxe.

Of the three options, nfsaxe was the only one I could get working. I had copied the RedHat CD to a folder in Windows and pointed nfsAxe there. I then mounted it on the RedHat installer on the 386, but it quickly failed trying to find files.

Looking at the logs on the 386, I could see it looking for 'RedHat'. Looking at the folder on Windows, I could only see 'REDHAT'. I knew that Linux was case-sensitive, so I realised that this wouldn't work. Once in the RPMS folder, I then saw that all filenames were in capitals and the old 8.3 format!

Oh shit... Windows is reading the CD as ISO file format and not Linux... I couldn't work out a way to get around this natively in Windows. Instead, I had to copy the files from a Linux machine into the NFS server on Windows. As previously mentioned, I'd set up a Linux machine on another box, so I booted this up and mounted the NFS share on Windows. It all worked and I started copying over the CD's contents! Here you need to realise that nfsAxe has a 30-minute trial period! If it detects file activity on the NFS server, it'll start a stopwatch and shut the server down after 30 minutes.

So, the experience was terrible and took quite a few attempts, but the CD was copied over to Windows. I then booted the 386 and pointed it to the NFS. It found the files!! Installation started and showed an estimated time of 1.5hrs to install. Hah. That wont work... the NFS server, even with a freshly timed restart will only stay up for 30 minutes.

Using a virtual machine?

TurnKey Linux has a fileserver image that, when spun up, provides a 'NAS' style linux machine. I downloaded the ISO, set up a VM on Hyper-V and got it going pretty quickly. You'll need to run service nfs-kernel-server start to start NFS as it's not enabled by default. The exports are all configured, so you can test it locally with mount localhost:/srv/storage ./test and see that you can loopback to yourself. I then mounted the CD and copied the guts into that folder.

Meanwhile, the 386 couldn't see the share. I tried disabling nFS v4 and then NFS v3 (at this point I couldn't even loopback mount as V2 is not supported!) but nothing worked. I was worried that it was a network bridge issue between the physical machine and the virtual. I had the NIC set to the physical adapters 'bridge' in Windows, but ... meh ... it hated me!

Enabling an NFS share on 'Workstation' Redhat

What next? Let's set up a real physical NFS server on that RedHat 5.2 machine I mentioned earlier. I'd done the 'workstation' install, so NFS wasn't up and running by default. Firstly I edited /etc/exportfs and added /mnt/cdrom *(ro) as the first export. A reboot just threw 'permission denied' on the 386.

Trying to mount this as a local loopback threw permission denied also? Did that mean a firewall? Folder access? Where am I actually denied? I really had no clue at this point as I thought I'd done everything as needed. NFS seemed to just be a very built-in thing for Linux and should just-work(tm).

If no options are passed to the /usr/sbin/exportfs command, it displays a list of currently exported file systems. Ok, let's check... no.. let's not check... the exportfs only accepts -a. Ok... stuff it... time to install a real version of the OS.

After re-installing RedHat 5.2 in 'Server' mode, I type net *tab* *tab* and to my surprise: netconf appeared...

DSC00270

DSC00271 DSC00272 DSC00273

Hah! I wonder if this was there in 'workstation' version? We'll find out once the 386 is installed. I set /mnt/cdrom as an export and ticked all of the dangerous options. The bloody thing mounted locally and also worked on the 386.

DSC00284

Yeeey... activity on the RedHat 5.2 Server CD. We could finally get this installation started... and completed...

5 hours later...

The installation completed and I was prompted to remove all boot media and restart. I did as requested and... hahaha... what the hell... the screen just kept scrolling the magical number 04. The picture below is funny as you can actually see the redraw/scroll at the bottom edge.

DSC00001

Seems someone else has had this problem also. I let the installer configure the disks, so maybe it got the bootloader wrong.

Hah. Nice. So I then re-installed using 'custom' and also opted to make a rescue boot disk. I chose to install LILO in the MBR and got the same screen as above. Fortunately, the boot disk loaded the hdd perfectly.

It made it to the console... but it took around 6 minutes to boot. I then bit the bullet and started the x-window-server.

DSC00292

DSC00293 DSC00295 DSC00296

It actually failed to load anything past the xterm. The dock to the right nearly loaded, but bombed out and disappeared. The xterm was functional... slowly. I checked top and saw that there was swap memory, but no physical. This poor thing would be thrashing the page file and not getting anywhere. So, although I already knew the answer, I tried to launch netscape-communicator. No chance... it froze.

Therefore, RedHat will run! But don't expect X11 with 8mb of RAM. Use it for ... a file server? Am sure it'll serve up the web also. Good luck.

Filed under: Retro No Comments
9Mar/170

Using your Sega Dreamcast on a new TV

I had recently been playing my Dreamcast on my old TV, which had a VGA input. Using the DC VGA BOX, I had VGA and audio output from the Dreamcast and all worked perfectly.

DSC00308

In the last fortnight, I've picked up a brand new Sony KD49X8000D and it doesn't have VGA input! HDMI, Composite or Component... they're the options. It was time to browse eBay for options.

VGA to HDMI

Without doing any research, or reading the product description, I jumped straight in and purchased a cheap straight-through VGA to HDMI cable.

DSC00305

It was never going to work. It seems to only be for projectors where they transmit random signals via VGA plugs. Don't expect that an analogue VGA signal can just magically transform inside a cable to HDMI.

VGA to RGB

I then saw this cable at trash and treasure last weekend. It's got VGA at one end and RGB on the other. I thought that it might be component, so I paid the handsome sum of $2 to test it out.

DSC00307

I'd forgotten to test it, but just read online that it also wont work. The description of a similar cable here indicates that this is for specific projectors under specific circumstances.

MINI VGA2HDMI Adapter

I resorted back to eBay and looked for an 'active' adapter. I found this one, cheap, on eBay and thought I'd give it a go.

DSC00301

DSC00302 DSC00303 DSC00304

In the end, the cabling is a nightmare as there aren't nice small VGA cables available.

DSC00309 DSC00310 DSC00311

Super simple to connect. But it didn't work first off. Someone else has made this item work before, so I must have something wrong with my configuration. It could also be that my TV doesn't support the resolution over HDMI.

Uhmm... nope.... I then tried another HDMI cable and realised that this one seated in around 2mm further! And worked! Switching back to the other HDMI cable saw it working too: it just needed a bit more of a jab to make proper contact with the converter. Note! These converters are cheap and cheerful, so do be careful when hooking them up.

DSC00002

Check that out... you can see the TV LED at the bottom... that's the initial picture at 1:1 640x480. Very clear!

DSC00005

And then scaled... looking great. Sounding o..k.. a bit scratchy at times. Will check my headphone cable between the devices. Anyway. Success!

Filed under: Retro No Comments
7Mar/170

Burning M27C256B EPROMs with a Willem

This is another public service announcement. I've just wasted around 3 weeks trying to burn an EPROM which shouldn't've taken more than 1 minute. I purchased a Willem Parallel Port 5.0 PCB burner from eBay (cheap, I know) and although I could happily read chips, I couldn't write them.

The settings were correctly configured for the M27C256B chips. You need 6.2v to write and 12.75v external. This means you can't use the USB to power. This PCB 5.0 is dual power, so it should've selected the correct source.

Every time I tried to burn I got the following error: Error at 0x000000 chip = 0xFF buffer = 0x58. Note that all three of those values would change, a lot. 0x24 and 0x46 were frequently seen yelling at me.

eprom burner

Turns out that the 'latest and greatest' version of the software doesn't select the correct power source. Downgrading to 0.97ja (as per the screenshot above works fine.)

So if you're getting the errors as I was above, then use the 'alternate' version that should be on the driver CD that you were provided with.

3Feb/170

NEC PC-8201A Portable Computer – Black Screen

Here's a new acquisition. It's an all-in-one portable machine from the early 80s. It was sold cheaply as non-working and, indeed, it non-works.

DSC00081

DSC00082 DSC00084 DSC00085

I hadn't realised how big these things were!? I was expecting something around half the thickness and maybe 60% the width/height. It's actually a really nice machine and I do like the form-factor. This item came quite scuffed and 'used'. All to be expected and nothing to worry about. I purchased it since they seem to have a great array of I/O ports and programmability. They run Microsoft BASIC off-the-shelf and have 32kb of storage.

Initial Inspection

First signs of tear-it-down-before-turning-it-on showed up as soon as I checked out the battery pack. The batteries weren't in there, but there was a LOT of corrosion. The circuit board in the battery pack even seemed to have components missing? Did they corrode and disintegrate away?

DSC00088 DSC00089 DSC00095

After a good scrub, all was much cleaner... I had already decided to pull the main machine apart first though. Corrosion has a magical property of travelling inside metal (just like electricity) and conquering whatever it can get its green rusty mits on.

DSC00097 DSC00105 DSC00106

DSC00102 DSC00103 DSC00104

Of course, it had spread. The terminal and battery pack isolation switch were the main victims. Fortunately, it didn't seem that the tracks or other components were affected?

DSC00107 DSC00108 DSC00109

DSC00113

Both Isopropyl alcohol and cleaning wipes were used to clean up the board. Light scrubbing was also required in the hard to get areas.

Powering it up

After all the cleaning and soldering above, it was time to bite the bullet. I found 4 random AA batteries and slotted them into the pack. My multimeter showed 6 volts, so I slapped it in an gave it a go.

DSC00100

Flicking the power switch on the side gave no response. I had read online somewhere that the first thing to check is the "Back Up Power" switch. I initially thought this meant "use the internal battery", but it doesn't. It actually means "use the batteries you've just inserted". With this switched over, the power switch on the side saw the unit come to life... well... there were at least a few electrons flowing.

Black Screen Of Death

For now, we're going to disregard the damage to the LCD. you can see that something pointy has taken out a sizable area of the screen... but 95% of it will still be usable prior to needing to replace that.

DSC00115

After the power switch was flicked, the screen produced the result you see above. Trouble-shooting this is pretty straight forward. As per the instructions here, press Enter, then type BEEP and press Enter again. If you get a beep, then your mainboard is fine and your screen is crap. My mainboard was not fine!

The next bit of googlin' found this result on diagnosing and repairing a black screen. Turns out one of the 245 chips was only half-functioning. I love that the author also found errors in the service manual. Either way, the repair-man found a defective IC and replaced it... as that I had no way of determining what was defective, I started replacing everything.

Component Shopping List

From the service manual, I found the following replaceable chips at my local electronics store.

Original Chip Jaycar's Version
40H139 : U1, U53, 74HC139 (ZC-4848)
40H386 : U51 74HC86 (ZC4835) IS NOT PIN COMPATIBLE!
Jaycar therefore doesn't have a replacement.
40H245 : U13, U42 74HC245 (ZC4870)
40H373 : U15 74HC373 (ZC4874)
40H367 : U??, U?? 74HC367 (ZC4872)
40H138 : U2, U3, U4, U5, U6 74HC138, but Jaycar doesn't stock it!
40H175 : U11, U12 74HC175, but Jaycar doesn't stock it!
603 Transistors BC547?
115 Transistors BC556/560?

Note: The above list is a work-in-progress. I'll update this as I continue identifying and replacing parts.

Find and Replace

Removing components from PCBs is always a challenge. Even with the best solder-sucker, you can still have a very hard time making sure every pin is free. In the end, as long as you don't need the existing IC, snipping legs and then removing those can be a much better option.

DSC00119

DSC00120 DSC00122 DSC00123

DSC00126 DSC00127 DSC00129

I've used sockets for each IC I'm putting in as well... I've no idea if this whole board is pointless, so I'd prefer to waste a socket more than an IC. I started with the 245 that was mentioned above and got nowhere... still the blank screen... I then replaced a 367 and had no luck either. This was really a crap-shoot and a very slow process. From here I thought there had to be a better option... so I consulted the service manual.

Troubleshooting via the Service Manual

I really should've started here when diagnosing the issues in this machine but, when I had first read it, I saw the word 'Oscilloscope' and got scared off. I don't have one of these, so I didn't think to pursue this area of investigation. I had since come back to it after realising that replacing each of the ICs was going to take a REALLY long time.

On page 54 you actually get to test each of the pins on the CPU itself. It indicates the pin and the expected voltage. Note that the CLK pin is meant to flip/flop and this can't be seen from a multimeter. All you can really look for is a 'half' voltage, as the flicking effectively provides 50% 0v and 50% 5v totalling 2.5v. All of the pins on my CPU came up OK as per the values stated!?

From page 85 of the manual, you get instructions on what voltages are meant to be seen from the power supply board when the computer is powered on. All but one of these turned out to be OK. Pin 10 was meant to be greater than 7.5v, but mine was only just over 7.0v. The manual then tells you that U2, Q16, C1, or D7 of power board are bad. Ok... this is good! Let's replace everything we can.

Something weird happened next. I didn't have the required components to repair the power supply, so I tidied up the desk for the evening. As I put the machine back together (aka. placed it into a pile of loose parts), I accidentally toggled the power switch.

DSC00137

Wait... what... we've got movement! The screen displayed a bunch of random rubbish. Sometimes a cursor, other times a heap of LOAD statements and at one point I could even type in a command... I didn't get a BEEP though.

DSC00131 DSC00134 DSC00135

The only thing I can attribute this to is that the power supply board received attention. I had shifted the caps around and also wiggled transistors. Maybe some of these had faulty solder joints? I should've measured pin 10 again here, to see if it all happened because of a 7.5v reading. Unfortunately, I couldn't get it back into such a state. I went ahead and purchased parts to fix the power supply. Unfortunately, I couldn't find the correct transistors at Jaycar to replace Q16 as per the instructions above.

DSC00138

DSC00140 DSC00143 DSC00145

I replaced all I could but still couldn't get the machine to do what I wanted. Actually, as I first started tinkering, the display of crappy text was satisfying. Towards the end, I hardly had a jumble of pixels. Toying with the ROM did seem to help... I wonder if the chip or socket area was damaged? Maybe static had fried it? Out of desperation, I attempted to swap some transistors around on the power board. Maybe that Q16 was the final issue. I did note that the 7.5v was still very intermittent. It didn't quite appear when the machine was half-working and only appeared at other random times... maybe the board was pulling too much current due to other issues and therefore was never actually going to let the power supply do it's thing?

DSC00147

Playing switch-a-roo with transistors revealed some information on the power supply. Swapping the 603s between Q2, Q16 and Q3 made either the speaker click, the relay click or nothing at all. To me this meant that one/some of the transistors were faulty. It didn't matter which as I didn't have a replacement. Trying to find actual 603s was impossible but, using the cross-reference tool here, I have just found out that BC556s are a valid substitute.

Or are they? Let's rewind a bit... I assumed that the transistor was a 2SA603... but it actually can't be. Using this complimentary transistor table, it seems that my transistors are 2SC2603 and 2SA1115. It would make sense that one was NPN and the other PNP. I therefore need BC547s (although they seem to be rated 100mA less and the pins are reversed!) for the '603' and BC560s for the '115'. Unfortunately, Jaycar doesn't have 560s, so I'll choose 556s instead, which are just have a higher voltage tolerance and a lower amperage. I might also order the correct components from eBay.

DSC00013

So, transistors... turns out that on page 108 of the service manual, the components are listed. I was totally correct on the transistor model... well, after I corrected myself. I therefore bought 20 of each from Jaycar.

DSC00001 DSC00004 DSC00005

Of course, I jumped the gun and didn't correctly review each component. The pins weren't backwards, they were actually out of order!

DSC00015

So, with the legs crossed, just enough, the order of the pins could be adjusted...

DSC00017

Whilst replacing the transistors, I also replaced the capacitors. Of course, one had to have exploded. Happened to be the 33uf that assists with the -5v output. I assume it's a cap that stabilises the voltage. I simply used solder to bridge the damage.

DSC00009

The results started off erratic... but then seemed closer to rendering a real screen?

DSC00021 DSC00027 DSC00026

And then it happened!

DSC00029

Keyboard didn't work.. screen was frozen... but shiiiiit... that's the actual main menu! I actually nearly have a real computer! I then replaced all the signal diodes on the power supply.

DSC00031 DSC00033 DSC00034

With the diodes replaced, the keyboard worked! Note that at this point in time, the board relay was not actuating on power on. It had previously, intermittently... but doesn't seem to be essential? Either way, as above, the menu worked and BASIC loaded. Unfortunately, once loaded, BASIC was useless with a screen full of junk. Any keypress resulted in Memory Full and a system beep.

DSC00037

I opened up TEX, typed in the obligatory sentence, pressed enter and the machine froze up... the work continues!

One step forward...

And then back to the beginning. I did something stupid over the weekend. On Saturday night I placed the ICs I had purchased over the top of the ICs they were to replace, so as to be able to see what ICs I still needed to replace/purchase. With these piggy-backed loosely, I closed the machine and put it aside.

Forgetting that I'd done this, I attempted to boot the machine the next morning... It presented the infamous black screen and not much else. As I shifted the machine to the center of the workbench, I heard parts move and instantly remembered what I'd done the night before. What a bloody waste of time I am; forgetting that I'd left the ICs in there and hence possibly doing all kinds of damage.

For the life of me, I could not get the machine back to where I was on Saturday afternoon. Such a let down! The only real goal was to hope that I'd only damaged mounted items and not the new items I'd purchased... then again, I could just re-purchase as I'll socket all the ICs.

IC Replacement

Solder suckers are fun, but Desoldering Braid is the best thing since sliced bread! Once you've removed the IC+legs from the mainboard, you'll find it quite difficult to remove the solder from the holes. Desoldering braid does this for you and does it quickly and cleanly. All you have to do is unreel enough to cover the hole and then press your soldering iron directly into the center of the area. The chemicals in the braid them somehow manage to attract the solder!

If it doesn't work the first time, then re-apply solder first. Only use the braid on holes that are full. If there's a gap, then the solder wont jump, it'll only flow! Also, the longer you hold the soldering iron there, the better. Watch as the solder flows into the braid and lift when it stops flowing up.

After removing the TC40H386P, and thinking that the 74HC86 was a replacement, I worked out that it wasn't. A hack was employed to get around this.

DSC00052 DSC00053 DSC00058

I lost a lot of faith with hacks like the above. Regardless, I ended up replacing half the chips on the mainboard and didn't get anywhere... it was time to wait for the oscilloscope to arrive.

Filed under: Retro No Comments
31Jan/170

Power Mac 7220: Optical Drives

The Power Macintosh 7220 was built cheap and used off-the-shelf PC hardware, including IDE CD and harddrives. Due to this, upgrading the CD drive is relatively easy... or it seems it would've been... when IDE CD drivers were popular! Nowadays everything is SATA and so finding a good IDE CD drive can be difficult. You'll find them on eBay, but they'll be marked as vintage and people therefore think they can raise the prices.

DSC00002

Fortunately, in one weekend I managed to acquire a grand total of 6. I bought 2 on eBay (a standard PC version and then another since it was an actual Apple model) as I was sick of not finding any, but then stumbled across another 2 at Trash and Treasure (Australia's version of Flea Markets or Swap meets) the very next morning. The following post is an effort to detail the pain and suffering of finding out how (in)compatible the drives were.

LG CED-8080B

I actually found this at a thrift store last weekend for AUD$5. Initially, installed into the Mac with cables connected, it stopped the entire machine from booting. It was about to be shown the bin, but I chose to test it again once I'd had the rest of the drives (and a strategy) and the bloody thing decided to work.

DSC00022 DSC00021 DSC00023

It wouldn't boot the Mac OS 8.0 CD that I had burned on Windows (but this seems to be a common trend... note that the CD image is now deemed unbootable!) As another test, I installed Toast 4.1.3 and found a blank CD-R. Using Toast's "Disk Copy" method, I created a new temporary CD volume and then dragged the System Folder over from my main startup disk. Toast burnt all this to the CD (with the bootable flag) and the CD booted!

Pioneer DVR-106D

Very plain-looking Pioneer drive. Expecting good things from a quality manufacturer.

DSC00019 DSC00018 DSC00020

Again, it wouldn't boot the image burned via windows. I therefore tried something different: I imaged the burned Mac OS 8.0 CD to the desktop, mounted the image and then attempted to re-burn the image to a new blank CD with the bootable flag set. Unfortunately, I couldn't actually successfully burn a CD with this drive. No configuration or speed setting (buffer-underrun protection included) would work!

DSC00035 DSC00036 DSC00037

Another point: ejecting the tray saw it get sucked straight back in again... a fault of Mac OS or the drive itself? If you were quick you could snatch the disc out.

Pioneer DVR-108

Quite similar to the previous Pioneer, this is a very plain looking drive. Based on the previous drive, my hopes weren't so high!

DSC00016 DSC00015 DSC00017

This drive also failed to burn every CD I tried. Even on standard settings (16x), it threw buffer underruns. Switching on the buffer-underrun protection did nothing to help. Burning at lower speeds (all the way down to 1x) with underrun protection still failed miserably.

Don't use Pioneer drives with old Macintosh machines. Seems that it takes too long to spin up and the machine fails to have the data ready?

At this point I switched back to the LG CED-8080B that I knew worked... just to make sure my process of disk imaging was stable. It happily burnt the disk image! Of course, on reboot the Mac just showed a question mark. It had no intention on booting my 'bootable' copied-twice ISO.

DSC00046

Note that, once back in the OS booted off the HD, I could still happily use the installer on the CD. It just wasn't bootable.

LG GSA-4167B

This one is listed as a Super-Multi. I'd usually be happy with this level of functionality, but the above results indicate that the Power Macintosh itself may not be able to cope with a drive that can spin too fast.

DSC00012 DSC00013 DSC00014

Either way, it still is a really nice drive... smooth, quiet and fast. The best part is that it burned the CD with no issues!... but it proved that my CD burning idea was incorrect. You cannot convert a non-bootable ISO burned under Windows into a bootable ISO this way.

Note that this drive does not open with the case on. The tray face is too large to fit through the space provided in the front panel of a Power Mac 7220 case! This is sad.. it's the best drive of the bunch, and I didn't feel like hacking it to make it fit!

Apple GCC-4480B

Smooth drive. Happily imaged an 8.6 CDR ISO in a matter of minutes. Note that it does not have a drive activity LED on the front.

DSC00007DSC00009 DSC00011

The image was then burned back to a CDR with the bootable flag and the image booted! The flashing disk with question mark showed up for a split-second and then it convinced itself to boot!

DSC00047

Feeling motivated, I used this drive to try and re-build the Mac OS 8.0 ISO into a bootable CD, but the drive also refused to boot it. Turns out that ISO itself is to blame?

This drive also doesn't fit correctly behind the face of the Power Mac 7220 case. Due to the missing front plate on the drive, the eject button doesn't mate and therefore the drive is rendered useless when the case is put back together.

Apple CR-583-B

This is the original drive that came with the machine. This has a little sticker over the eject button (but the button still works) and an activity light which is obscured by the front case.

DSC00004 DSC00005 DSC00006

This drive happily booted the OS 8.6 ISO that was re-bootable'd using the process above. This contradicts my initial impressions of "not being able to boot a burned CD", as ... well ... it does boot them. You just need to make sure the burned CD is 'correct'.

Of course, this drive is not a recorder... hence why Toast was telling me that no recorder was found. I even rebooted the machine to find the recorder... I can assure you that rebooting did not turn it into a recorder!

Which Drive?

After trying out everything above, I had to settle on a drive. I didn't want the original as it didn't have the 'tabs' to hold a CD in when the drive is mounted vertically. I also wanted to use an Apple drive, but the one's I had wouldn't really work with the case or weren't a burner. Instead I chose the black LG and modified it's tray face-plate to fit through the Power Mac's front fascia. This required a little filing on the ends of the tray.

DSC00049 DSC00052 DSC00056

In the end, it works like a charm!

Filed under: Apple No Comments
24Jan/170

B75 helps out Qube on the Maryvale Paper Train

This freight train operates in South-East Victoria. It runs from the terminal at Dynon and carries containerised paper products to and from the Australian Paper mill at Maryvale.

Qube operates the service and is often changing the motive power around. They have a good selection of locomotives, but recently have suffered a few failures in their more powerful units. Due to this, there's been a random selection of lesser-powered locomotives, meaning more units and more variety.

23th January 2017

The word had spread that B75 had been leant to Qube and would be leading the nightly service. It usually passes South Yarra just before 8pm, but, of course, was running late last night. Fortunately there was just enough light to snap it.

DSC00104 DSC00112 DSC00117

I was hoping it'd take the down Frankston line, but it instead stayed on it's usual down Pakenham. You could hear it coming.. the B sounded awesome with the S and VL behind it making just as much noise.

DSC00127

Nice and dark at 8:32pm, but I'm still happy with the result.

24th January 2017

Turns out this might be a regular event! The G classes must still be out of action. Nothing like a bit of sunlight to help out evening photography.

DSC00128 DSC00132 DSC00133

DSC00140

DSC00146

DSC00144 DSC00148 DSC00149

DSC00150

25th January 2017

This time I tackled the train head-on from platform 2 at South Yarra station.

DSC00152 DSC00155 DSC00165

Still looking just as clean and tidy as ever.

DSC00166

26th January 2017

This was to be the final day that B75 was helping out... It seems that the drivers wanted to do something special, and so instead of just driving the consist back, they ran B75 around at Morwell and had her lead back. It was also Australia Day, so there were flags hanging from the wing mirrors.

DSC00047 DSC00049 DSC00055

DSC00053

I really want to thank Qube for putting this show on!

Filed under: AUS No Comments
23Jan/170

SCT begins Melbourne to Brisbane freight services

SCT has always had an agreement with Aurizon to provide a small loading for north-bound freight services. This has recently expanded into a full-sized consist and SCT are now running the services themselves. The very first Melbourne-Brisbane service ran on Saturday the 21st of January 2017, departing the SCT Laverton terminal just after 8pm.

Thanks to daylight savings, there was a chance to actually get a photo around Sunshine Station. Aptly named in this circumstance... The area provides a view of the BG and SG tracks, with a set of grain silos as a backdrop. The usual V/Line and Metro services provided entertainment whilst waiting for the freights.

DSC00007

DSC00010 DSC00038 DSC09988

The Melbourne-bound XPT bolted through, only a little bit late.

DSC09993

Aurizon then came through with 7BM7, only to later have an extended stay in Wagga Wagga. I do love that they cleaned the grime off the front logo.

DSC00021

7MC2 started to depart Dynon, but the XPT also jumped. The XPT was therefore given priority.

DSC00045

7MC2 then spooled up. From Sunshine, you could hear it accelerating from stand-still over in Tottenham.

DSC00056

It sounded and looked fine as it passed... but it failed not too much further down the line, crawling into Seymour. It didn't continue its trip to Junee until the next day when two other locomotives joined it.

Up next, the SCT consist. SCT011 was attached at SCT Laverton to pull the whole train out of the yard and onto the main line. It then detached and SCT004 had the honours of pulling the train around the bend at Spotswood and over the triangle. From Sunshine, the train could be heard well before it was visible, as the wheel screeching over the triangle was tremendous.

DSC00073

DSC00070 DSC00078 DSC00079

It had an interesting consist, with the crew car 7 cars back from the locomotives.

DSC00084

And that was a wrap... the sun hardly held up for the late departure... I might try and get it earlier down the track next weekend. It's really great to see more colour on the eastern corridor.

Filed under: AUS No Comments
16Jan/170

The annual Christmas pilgrimage – December, 2016

Just like the christmas trip in 2015, this trip just past for 2016 Xmas wasn't overly different. Still a great location with a lot of sightings. An early start out of Melbourne meant an easy trip onto the Hume highway. I caught the southbound XPT just out of Kilmore and a southbound inter-modal in Seymour.

DSC09382 DSC09387 DSC09393

After a speeding ticket in Benalla, I b-line'd it straight to the Olympic Highway. It's a nice drive, off the beaten path, and away from influences to do stupid things on the road. First stop was at Harefield and I was greeted by an IRA 44 Class! Qube has taken ownership of a few of them and has been using one for the shuttle into Junee.

DSC09396

Not much was happening in the yard, so it was a bolt further north to intercept the southbound steel train. I beat it through Illabo, meeting it on a driveway half way between Illabo and Bethungra.

DSC09410 DSC09415 DSC09419

DSC09412

From there it was off to Cootamundra to tackle the XPT. I tried to beat it to Jindalee, but it won. Instead I then backtracked and got it at the station.

DSC09420

DSC09424 DSC09426 DSC09434

At this time of day, between the two XPTs, there's always a quiet time when the sun is at it's peak and the rails are buckling. Due to this, I took time to have lunch and check out the pool at the usual motel.

Back to it... the XPT was fast approaching from the south and I wanted to get it at Jindalee this time.

DSC09440 DSC09443DSC09446

DSC09444

DSC09450

And then something weird happened... an off-the-radar rail-grinder rolled through! I love being in the-right-place-at-the-right-time.

DSC09452 DSC09455DSC09466

DSC09464

And of course, being zoomed-in and distracted, I hadn't realised that the 81+82 on the grain train were steadily already rolling towards me.

DSC09470 DSC09474 DSC09478

DSC09475

The next train was a bunch of QBXs heading south to Junee. I had enough time, so I thought I'd try something different at Wallendbeen.

DSC09501 DSC09504DSC09509

That angle worked really well! I then caught them again past Jindalee on a driveway half-way back to Cootamundra.

DSC09514 DSC09520 DSC09524

They didn't slow down through Coota, so I kept to the limit and then got in front of them before Bethungra.

DSC09526 DSC09531 DSC09533

DSC09529

I had a really hard time keeping up with them once they were on the other side of the spiral. It's all downhill for them and me, but they were doing somewhere around 95km/h and made it hard to catch up when the speed limit was 100km/h. We were both fast-approaching Junee and I managed around a 50 metre advantage; just enough to park road-side safely and snap a shot above some lovely green pastures.

DSC09542

From here, it was Junee yard.

DSC09548 DSC09551 DSC09555

DSC09559

From there, it was back to Wallendbeen to catch the next southbound intermodal.

DSC09574

DSC09567 DSC09569 DSC09575

I got in front of it and made it to another driveway past Jindalee, but before Coota.

DSC09579 DSC09585 DSC09588

DSC09583

The sun was already starting to lose light, but there was still enough time to get the 2 QBXs that were coming in via Stockinbingal.

DSC09599 DSC09606 DSC09614

DSC09617

Nothing was next on the radar, so I checked out the yard at Coota. Turns out there was a bit of shunting going on to get a grain train to fit in the yard.

DSC09658 DSC09660 DSC09663

DSC09666 DSC09670 DSC09685

That steel wagon must have been defective as it was sitting by itself, blocking one road, to start with. It ended up being shunted into another road onto so that the arriving train could stash half of its wagons there. Pretty quick work actually. Nice to hear the 81s powering up and down when shunting a whole train to shift one wagon.

After this, it was dinner time... an early start on the radar showed, what should have been, a great opportunity for a cross at Yass Junction. Due to this I packed up and got on the road early. Thanks to my miscalculation, the pass actually happened around Goondah and the light was terrible. Instead I forged ahead to Yass and got the northbound grain there.

DSC09690 DSC09692 DSC09706

DSC09696

I really do like that angle. From the grain silo, instead of the platform, you can get a nice long telephoto shot of the descent into the Junction. From here, it was off to Canberra and there's not much going on nowadays with the Museum closed and the scrap metal train done.

On the way back to Melbourne, I saw an opportunity for a shot at Jindalee of a northbound grain train. This all lined up well ... very well ... as the-right-place-at-the-right-time happened again.

DSC09716 DSC09718 DSC09725

DSC09719

The grain train then appeared.

DSC09731 DSC09739 DSC09746

DSC09743

A quick stop was had in Cootamundra to snap the Lachlan Valley Railway sheds where they have a nice collection of railmotors and 47 class locomotives.

DSC09747 DSC09748 DSC09750

And then finally, after a pie at Culcairn, I caught up to a southbound freighter at Henty.

DSC09757 DSC09761 DSC09764

The dim weather on the way back turned much dimmer over Seymour where visibility actually dropped to around 10 metres. Most people parked on the side of the road; but I didn't see that as 100% necessary and a few of us kept on driving through the car wash.

Another awesome pilgrimage!

Filed under: AUS No Comments