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IBM PS/55 Z – 5530 All-In-One

I saw this on eBay and couldn't resist... I probably should have resisted... I also probably should have actually reviewed the specifications prior... but whatever... I made the seller drop it to a Pack'n'Send and it arrived, perfectly packed, in no time. It's a cute little unit. I actually had the 12" IBM VGA monitor back in the day as a single unit and loved it for its clear and sharp 640x480 picture!


The IBM Personal System/55 (Here's some more information) was a series of computers released in Japan back in the late 1980s. It was based on the x86 architecure, but used IBM's own Microchannel (MCA) system bus. I sorta wish I'd researched that point beforehand as nowadays MCA cards are few and limited in technology. Ethernet is hardly BNC co-axial and SCSI is rare. Audio is even rarer... but there were Creative and Roland cards! Good luck trying to find one!

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The front sports two slots for floppy drives, brightness/contrast and a lovely lever-style power switch. There's also your power and HDD LEDs. The swivel base is also a nice addition. There's even a lever on the rear to secure the unit once you've swivelled it to the point you like.

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There's a panel on the rear to cover up the VGA cable. This cable is a little strange... it seems to be an artifact from the fact that the whole unit is really just an IBM 12" monitor with a growth hanging from the base. Instead of running the cable internally, they actually have a midget lead and plug that is exactly the length required to fit into the Display Adapter card which can therefore only be in slot one. This becomes more apparent inside when you realise the card requires an extended slot and, you guessed it, slot one is the only such slot.


The whole PC area of the unit slides out once you unplug the VGA cable and unscrew the two black screws. I really do like the modular design! Note, it also seems this unit expects the keyboard to have a speaker in it? Interesting!

But what does it look like on the inside?

Getting access to the motherboard is super easy. Unscrew the two screws and then slide the whole lot out. Make sure you unplug the VGA lead first! The shelf that the motherboard sits on is easy to work with and provides access to drives as well. My unit didn't come with any... I assume the floppy will be standard? But the HDD definitely isn't. Jeesh. The MCA bus is also totally obsure and the graphics card is a Display Adapter IV. It also needs to stay in the top slot as that's the only extended MCA slot and it's also the only one the VGA lead will reach to.


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You'll note that with the motherboard removed, the case is still very much in-tact. Actually, it's sealed. Getting to the area where actual power supply and monitor are is a little more tricky. I wanted to give it a good visual inspection prior to powering up, so I endeavoured to open it. Turns out it's built to be totally tamper-proof and return-to-factory only! There are two removeable caps on top that present you with 'headless' screws. Yes, they're screws... but there's no ability to actually unscrew them.


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I made a total mess with my (fake) dremel to try and gouge a flat-head screwdriver slot. I ended up melting a lot of plastic... but for some reason I'd decided that the covers will go back over, so the mess is contained. Either way, the screws came out and the case came off.


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Yup, it's a CRT alright... and that power supply is totally embedded into the monitor housing. So much for an easy switch to a 240v supply. I'll revisit this once I work out if the motherboard is good. If it's not, I might just gut the whole thing. Back in '99, The Techtroid Box did just that.


Meanwhile, the patterns of dust on the inside of the monitor housing were slightly mesmerising!

Motherboard Layout

This is a flat AT style board. All integrated ports are along the rear. Some of the ICs have IBMs infamous heatsink shields that make them look military-grade. The MCA bus is obvious and two riser cards exist for a HDD and the 3 MCA slots. There's also a floppy header and some random jumpers.


There's a header at the top end that plugs into a socket very similar to a Commodore 64 User Port Edge Connector. This is fed from the powersupply that's intertwined with the monitor circuitry in the do-not-touch zone. Looking down at the board, with the edge connector pointing up, the pinout seems to be as follows:

-12v 12v 2.8v 5v 5v 5v 5v 5v 5v

So, above you'll find the top and bottom rows, as if you were looking into the socket inside the chassis from the rear. I have no idea if the voltages are correct as my machine isn't booting.

Does it work?

The unit requires 110v AC, so I used my trusty step-down transformer. After re-assembling the bare minimum, I applied power. The monitor came to life, but the motherboard was dead. There was a little bit of heat from the CPU, but no other life. No manner of RAM SIMMs helped. A closer inspection revealed that just about every aluminium electrolytic capacitor had started to corrode. Tracks were beaten in a few areas. Looking even closer, it also seems that the motherboard is 4-layer: tracks top and bottom with two plates in the middle... possibly positive and negative?

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I started replacing capacitors where relevant and testing tracks... No amount of effort brought it back to life though.


Turns out you can feed the motherboard connector through the front floppy slot and then connect it up... allows for much easier fault diagnosis!

Is it the EPROMs?

I intend on popping them out and reading the data off them. From a visual inspection of the code, I might be able to tell if they look OK? Maybe copyright data, etc... but I'll have no checksum to work with to determine if the images are correct. I'll also have no other images to load to test further...

Final answer: replace the guts?

I'll do this in another post. There's a few options for motherboards with riser cards on eBay and I'll need to choose wisely as I'll want the measurements to line up as closely as possible. Of course, I could just slap something in (as per The Techtroid Box's post), but I want it to be cleaner and more permanent.

Does the CRT work?

The video card is an IBM "Display Adapter IV". Supposedly it has an 1024x768 mode? Here's more information, albeit in the wrong language. And this article (scroll down to PC # 6) also indicates the resolution.

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I happily got 640x480 working... I'll spend a little more time later with 1024x768. First I'll find it some new innards.

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68-pin RAM SIMMs

I had previously picked up this Bravo 4/33 486 Machine and had assumed, from the photos in the auction, that it needed standard 72-pin SIMMs. A quick physical test proved this assumption very wrong. This was a proprietary motherboard and the slots were narrower than 72-pin SIMMs and wider than 30-pin! I'd never actually seen anything like this before. I then researched and realised that this board needed 68-pin SIMMs.


eBay came to the rescue and two 4MB SIMMs arrived from Denmark! Seems they're mainly used in Roland hardware or Macintoshes. Anyway, from the photo above you would easily mistake them for 72-pin SIMMs. It all becomes obviously when you line up all the types...


Above we have a 128-pin SIMM, a 72-pin SIMM, two 68-pin SIMMs and then a 30pin SIMM. I think quickly tested in the motherboard and success! They fit!


Of course, the machine still didn't boot... time for more mucking around... (and no, it wasn't the fault of that loose screw...)

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Japanese Railway Freight Timetables

These are the freight watchers guide to Japan. They include both JR Freight and private companies. I've previously used them to chase The Gakunan Railway, the Seino Railway (Minoakasaka) and the Chichubu Railway. Oh! Also the M250 Super Rail Cargo run by Sagawa Transport! (also see here) .. I recently picked up the latest copy...


Anyway, I looked at my shelf recently and realised I've got the collection from 2010 through to 2018! All of these have either been ordered from Shosen Books in Akihabara, or direct from the author website.


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In each of them, if bought brand new, you get a calendar and the run diagrams. These diagonally plotted timetables show you the train paths and their layovers. It's really handy to find the places with the most crosses. Actually, I used the same mechanism when chasing The Southern Spirit here in Australia.


Note to the left is the main freight timetable from 1964 when the railways made the huge final switch from Steam to Electric/Diesel. It's known as yon-san-tou... (4,3,10) which translates to: October 1968, i.e. the 10th month of the 43rd year of Showa. At some point I want to actually compare large chunks of the timetables to see if there's any interesting correlations.

Until then, the goal is to just chase more freight in Japan! If you need a hand with information that might be available in these timetables, then drop a comment below.

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Osaka Higashi Line Update!

I was just browsing satelite maps of Osaka and found that they'd expanded the bridge! (Previously reported here)


From above, you can see the western on/off ramps are complete. The eastern side of the bridge has also now completely crossed the river. Actually, the construction equipment has also been removed!

The tracks were also re-aligned down at Shin-Osaka station...

2018-02-27 16 05 28-新大阪ライブカメラ (Sin-Osaka Cam) - YouTube

You can see a whole lot of over-ballasted track in the bottom-to-mid-right of the image above. That's where the tracks will merge in from the above ramps.

The railway was 'optimistically' meant to open last financial year... so we're already 2 months behind... but the construction is looking very promising!


6029 Returns to Canberra (for a weekend)

The irony... or, at least I think it's irony? I don't know anymore. But, whatever, I didn't need an excuse... what a great reason to return to Canberra for the weekend! 6029 came back to the place where it had been stored for decades and then rebuilt (to then assist in causing the failure of the railway museum) to run tours to Queanbeyan and Bungendore.

Here's the event link, but I can't see that link lasting long at all. It's not overly unique? Anyway, the basic idea was 4 shuttles to Queanbeyan on Saturday morning, followed by a single afternoon return trip to Bungendore. Then sunday was three full return trips to Bungendore.

The Line

It turns out that Canberra was an afterthought. To get to Canberra, railway vehicles first traverse the logging line to Bombala, but only until Queanbeyan where the Canberra branch actually starts. Railways were always about freight... and Canberra hadn't been invented yet... so the line that exists between Goulburn and Bombala was actually due to the need for wood, with an extension to Canberra built later.

It's a very short trip between Canberra and Queanbeyan, hence why they managed to schedule in four shuttles on the Saturday morning. There's not much along the line as it's quite flat between both stations.

Getting to Canberra from Thirlmere

It turns out that this was part of a larger rail cruise. Cruise Express ran their Southern Rail Spectactular event from Sydney to Melbourne and return. It included branchlines, steam engines and multiple consist changes. SRHC even got their standard-gauge consist set up for this specific event! It was also fun watching the consists hold up traffic in either direction...


And again Northbound...


Saturday, 1st September 2018

GL112 was attached on the rear and the train made it into Canberra Railway Station (Kingston) for it's first trip at 0900. All went well and I was waiting on the northern side of Jerrabomberra Creek. Beautiful sunlight and only 2 other onlookers.

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From there, I attempted to get the return from the back of Bunnings in Fyshwick, but there were no good vantage points. The carpark at DFO would've been on the wrong side, with the sun directly in ones face. A quick shop at Jaycar for a DB9 socket for a mouse rebuild and then off to the back of Nick Scali furniture to catch the 10am outbound.

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Another two onlookers... one being naughty on the wrong side of the fence... and then it was off to Queanbeyan to watch the return shuttle.


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From there, it was family time for lunch. I managed to watch the 12pm shuttle depart before this... not before seeing a whole range of stupidity though... people just seem to think that crossing a yard is appropriate? They were quickly told to move on!

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4201 then rolled in with a NSWRTM water gin!? I love unexpected surprises! 6029 then departed.

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Later in the afternoon, I found enough time in the afternoon to watch the Bungendore return trip at the bridge just past Queanbeyan station. Lots of interest here this time and great sunlight. It's an awesome spot for inbound movements.

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Sunday, 2nd September 2018

First-things-first on a Sunday morning in Canberra: Jamison Trash'n'Treasure, Mitchell Tip Shop, Woden Trash'n'Treasure and then Mugga Tip Shop. Found a few tid-bits, but nothing to call home about. Actually, Mitchell Tip shop was a bit out of control: they wanted AUD$25 for a monitor and set of computer speakers... what kind of 'gourmet' do they think they're selling? It's literally rubbish!

Made it back home to switch cars and then to Kingston railway to catch up with friends to grab some aerial video of the Bungendore shuttles. In the yard, 42103 and 4201 were hanging around, keeing the crowd entertained.


First stop was to be the bridge at Burbong, NSW. It's a great location, amazingly scenic, but the sun isn't always in the best location!

Fortunately, for a drone, the sun is absolutely no issue. Line-of-sight with too many trees can be... but we managed to find a great location. Nathan even had the 'VR' headset so I was watching the drone's viewpoint as he was flying it... pretty damn amazing!

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The train came in due course and ... it was beautiful. The locomotive was at full-tilt (the exhaust may well exclaim that) and the sights and sounds were awesome. It passed quite quickly but we caught further footage whilst everyone else was packing up.


And now, the best part... the drone footage! (Make sure to turn the quality right up!)

The next spot was in the Molonglo Gorge. I'd actually never been here... even though I'd lived in Canberra for ~28 years. Seriously disappointing actually, as it's an amazing location! The railway line snakes along the gorge hill-side through two tunnels and there's a few spaces along the access roads to get some great shots.

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Another pilot had a drone out (exactly the same model) and our flight paths were negotiated to not get in eachother's way. Not exactly an easy thing to do as your viewpoint from the drone can be based on the film you're trying to take rather than the drones around you... and they can also have the same idea... so we had our wits about us. There's also a no-fly-zone towards Queanbeyan, but we were far enough away from it.

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After that, it was back to family time before jetting back off to Melbourne. Usually my weekends are pretty quiet in Canberra, but this one was fantastic. Can only thank the NSW Rail Museum for the entertainment!

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What RAM slots are these?

I recently found a relic on eBay. It's an AST Bravo 4/33 (not the LC!) and has a very proprietary motherboard. I'd seen the photos and I thought I saw standard 72-pin SIMM slots. Turns out I was totally wrong... I've never seen this size before!? There's a similar-but-not-quite motherboard diagram here, but the jumpers are in different locations. The strange RAM also doesn't get a mention?


Turns out they're neither 30-pin, nor 72-pin! Did AST decide to use Apple's proprietary 64-pin SIMMs? There are similar (68-pin) 256kb and 512kb SIMMs on eBay, but they don't match the pin-count and they're for VRAM in older Apples? There also seems to be other something resembling RAM soldered onto the motherboard, but I can't find any information to determine if that's actually RAM or just cache. Either way, the machine just beeps once when power is applied. The beep sounds like a standard "NO RAM" boot error. There's also a fried electrolytic capacitor.

...Actually, I just found two 64-pin 4mb SIMMs for an Amiga... Let's see if they work when/if they arrive...

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