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Commodore 64: Datasette Maintenance

So, Double Dragon had issues loading on a Tape Drive I'd acquired. It had come in a mouldy box, so I had a hunch that the drive itself would need a thorough clean and alignment.

There are multiple alignment tools, downloadable as disk images or PRG files. I could copy these onto my SD2IEC, but there was an issue: the SD2IEC gained power from the Datasette port which was now in use by the Datasette drive itself!

Powering the SD2IEC from the Datasette Cable

Fortunately, the Datasette plug has a screw that makes accessing the internal pins very easy. I opened it up, taking note of the cracked, flimsy plastic, and inspected the contents.

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The green wire, pin 2, is the +5v that we're after. Bare back some plastic on the wire so we can solder to it. I found a male+female standard round DC power socket to use. Make sure the female is on the 'power' side, otherwise you'll have a potential for shorts if there is exposed bare metal with current flowing through it. Of course, the outer metal is ground, but still better to be safer than sorry.

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From here I soldered on the plug and grinded out some plastic from where the main cable feeds in. This allowed the plug to hang out the end. Not the cleanest job, but it worked quite well. I sorted wanted to feed it out the side where the ground wire is... but I hadn't left enough length.

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Next, on the SD2IEC end, bare some wire also. Grab the plug and solder it on, then use some form of insulator to tidy it all up. Nothing a little duct-tape can't fix.

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Everything was plugged in and good to go!

Cleaning the head

Everyone recommends alcohol (isopropyl) wipes for this. The wipes have the benefit of leaving little residue and drying cleanly. You'll find that KFC wipes are also usable.


Take the swab out of the packet and wipe the heads, specifically the central metal one. I didn't actually know which way to wipe, or how much pressure to apply. So just be gentle and attempt to remove any visible dirt. Don't put a tape back in until everything is try.

Aliging the head

There are a few options here. Download Cassette Azimuth, also known as 'Recorder Justage', and Minimal Head Align. Both do the same thing, the former is more complex.

I copied them both onto the SD2IEC and then loaded them via the file browser. Cassette Azimuth is easy to work with. Load it up and then hit play on your tape. If nothing is happening then you'll need to start adjusting the player already. If you see data, and it's erratic, then you'll also need to adjust. The goal is to have straight vertical lines.

To actually do the adjusting, there is a tiny screw-hole above the rewind button that a small jeweller's screw driver will fit through. When the tape drive is playing, the hole lines up with the head adjustment screw. Turn this screw all the way clockwise (not too much pressure!) and then turn back in small increments as required. Pause between turns to let the screen update with the new readings.

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You can hit F1 to get the guide-lines for the data. I couldn't work out if the data lines were meant to draw over the top, or in between, or where... but at least I got them vertical!

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Here's the same process with Minimal Head Align. The app is much more raw; it starts off with a screen full of garbage which starts refreshing once you start feeding it data from the tape drive.

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Back to Double Dragon

I had assumed that all the loading issues were from a dirty/misaligned head... so I thought I'd try the game again now that the tape was producing cleaner, more vertical lines on the test programs. I didn't have much faith... but it worked! It took just as long as last time, but this time I got to the first level!

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The graphics are intense... hah. Controlling the character was hard at the start... then I realised it was because my controller probably hadn't been used in a decade. I'd found a sega mastersystem controller at a second-hand shop over the weekend. Works perfectly.

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So as the game was loading, it got to the point right before the title and asked me to reset the counter to 0. Turns out this is so that, when you die, you know where to rewind the tape to.

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From there you rewind to zero, press play... wait for the load and then have another go. I might try source the game on floppies to see if the extra data capacity allowed for a different version. Hmm... then again if this review is anything to go by, then there's no hope.


Commodore 64: Tape Drives

This was really a lesson in jumping in the deep-end. I'd bought Double Dragon for the C64 recently on eBay, somewhat blindly, and found out that it was on datasette. It had been relegated to museum shelf until I happened across a cheap tape drive. Below is the story of learning how these things work.

The Datasette drive arrives

The seller had mentioned 'original box' and 'complete'. Indeed it was. I take it, though, that the box had been in the back of the shed for quite some time. The manual pages were mould-glued shut and the box was probably releasing spores every time I touched it. Due to this, I took photos for historical-sake and then destroyed the evidence; keeping only the actual drive.

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The first game: Double Dragon

Double Dragon (for C64), released by Melbourne House (more information here), is a side-scrolling beat-em-up. The name of the company is confusing, as it sounds like it might be Australian, but was actually started in London. There is/was an Australian branch though, but it was known as Beam Software.

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I'd played this game with my brother decades ago on the 286/386. Actually, I think nearly every Australian kid who grew up in the 80s/90s would've played this on a platform somewhere... maybe sega/nintendo/x86/amiga/atari/etc... Or even at the arcade! Either way, I wanted to check this out on the Commodore 64.

Intricacies of a Datasette Drive

This device has a single cable that plugs onto the PCB edge-connector 'port' at the back of the C64. It's a similar connection to the User Port; very raw and very cheap for Commodore to produce en-mass. The cable also has a grounding wire, but I don't quite know where you'd connect this to?

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As you can see, everything was there, ready to hook up and run. I did just that, plugging the tape drive in, the power and TV. Switching it all on brought me to the usual BASIC prompt. I had heard the tape drive make a few faint clicks. The tape needed rewinding, so I let that run it's course (hah, how I don't miss having to do that!)

I'd found out, by accidently typing only LOAD previously, that this was the command to load tapes. After hitting enter, you get a prompt to press the Play button on the tape drive. So, at this point, I did exactly that. As I hit Play on the Datasette, the tape spun, then slowed down... then .... stopped......... Sure, this 30 year-old equipment had been stagnating in someones shed for decades... probably worn-out and dead.

As I was pressing the eject button, the tape started playing again... demons? ghost in the machine? not quite... turns out that a slight bit of pressure on the eject button releases the bottom-right 'guide' that keeps tension on the magnetic tape in the tape case as the tape is playing. This component was able to apply WAY too much tension and therefore effectively 'braked' the tape and cause the motor/band to slip.

'Band', you say? Yes. Band. No belts with teeth here... the drive mechanism is a cute little motor with a rubber band driving the other pulleys. There is then a further rubber band to drive the counter. 'How do I know this?', you ask? ... I took the thing apart as soon as I could!

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The bands looked pretty stock-standard. A quick google showed zero results for replacements... so... searching around the house I found some probably-too-small substitutes. Having a band too tight will probably pull on components and put waaaay too much pressure on old equipment that may not be rated for it; but hey, you can only try!

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Replacing the main band required 3 screws to be removed. See above. Once removed or loosened, you can slip the main band out.

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I then put my two replacements in. Lo'and'behold... the bloody tape started playing. The results? The screen went blue for 15.5 counts, the tape paused and then a message came up: Found Double Dragon! Woah.. then a slight pause and then the tape continued. Then it was ... rubbish?

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I gave up after 20s of garbage picture and noise... must be a crap tape or damaged head. But... it did recognise the data on the tape... I mean, it knew the name?

Another Tape: The Android

Along with the datasette drive, I also purchased a 5-tape set of miscellaneous games. I whipped the first one out, named Android and tried it. The C64 successully saw that it was indeed The Android and then ... more crap loading. Loosing heart, full bladder, too much Sapporo... I excused myself, letting it play...

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Returned a while later and.. WHAT THE!?... It loaded!? So... wait... those loading images are expected!? That crappy video that would trigger an epileptic fit and that sound that's drilling into my inner-ear is normal?

Android Control (different name on tape vs. name on 'found' vs. name on title?) loaded, I played it for 5 seconds... but I'll try that again later.

Back to Double Dragon

So, now knowing that I need to sit back and wait... I slapped Double Dragon back in again. It took the same 15.5 counts to the Found Double Dragon message and then 58 counts to the next message.

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Ok, we're getting somewhere... I hit space...

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DAMN! 3 minutes of waiting... first time around the tape actually reached the end... that actually indicates a data issue. Second time around I got the error above. So Android will load, but Double Dragon wont! Might have to clean the heads... Will report back when I have time to try again.