The Three Amigas! - Numero Uno (A500 KS1.2)

CosmicCruncher

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Completing my Amiga collection are these three machines...

Uno) Amiga 500 Kickstart 1.2
Dos) Amiga 500 Plus
Tres) Amiga 500 Kickstart 1.3
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(Sniffing out fishy caps, he didn't seem to find any)

I would like to get all the machines in decent working condition with some small quality of life upgrades. There are no major underlying issues with any of them that I know of so this should be a fairly easy project. I will be doing bits to my A1200 and A600 as well so this might all take some time. Check out my threads for those.

Lets start with the oldest Kickstart 1.2 A500. This one seems to have taken a beating with damage to the casing, a missing key cap and is a bit grubby but otherwise looks ok. This will also be a nice one to break me back in to the Amiga, I've never used them heavily so once again will be a learning experience.

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I took the opportunity to open up the case and inspect the board. I also discarded the RF shielding. Apart from being a bit dusty and dirty in places looks ok.

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I ran the Amiga Test Kit Diagnostics by Kier Fraser, all tests pass ok which is good news. The disk drive works without issue, loaded a number of disks. With the fundamentals looking good I decided to fully strip down and clean the machine.

First thing I wanted to do was attempt to repair the broken casing, if held in the right position the crack next to the cursor keys was barely visible so should be a relatively easy repair. The scuff on the corner I've left as is, not sure there is much that can be done with that. I opted for araldite epoxy for the repair, much stronger than superglue and probably now the strongest part of the case. After a couple of hours it has set enough to remove the excess but was still soft enough to do with a sharp blade. I then used a bit of scotch brite to smooth it, probably not the best thing to use but it was within arms reach 😅.It did a pretty good job. The finished result is smooth to the touch with hairline crack just visible.

Here it is mid repair prior to removing the excess epoxy:

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In the meantime I set about washing the rest of the casing and stripping the keyboard. The keyboard wasn't awful but you can't beat a fresh clean keyboard on these old machines.

I removed all the keys apart from the larger ones with support brackets, didn't want to push my luck by breaking something and I was still able to get underneath to clean. Here is a before and after shot:

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Keys out to dry after washing:

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Once fully dried I set about reassembly. Definitely more satisfying than pulling it apart :D.

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Just after that tense moment where you hope you haven't misplaced any springs. The eagle eyed will notice there is now an escape key, I stole this from the A500 Plus. This keyboard was purely a missing keycap and spring with the stem still intact and working. The 500 Plus is missing the decimal point key from the number pad but it looks like the stem itself is either missing or crushed so that one will need a more in depth repair when the time comes and I can source the required parts.

Fully reassembled at last:

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Once all the casing was dry I set about reassembly. While partially assembled I open up the floppy drive, gave the heads a clean and put a bit of lithium grease on the drive rails and motor spindle. The drive is still rather noisy when seeking but a little better. For those that have come across more than I have, are some of the drive mechs inherently more noisy than others depending on the design? They could have been like this from new for all I know, the newer 500 w/1.3 Kickstart is much quieter. I also gave the expansion edge connector and trap door connector pins a quick clean with some IPA.

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With that complete I set about completely reassembling the machine. Here is the finished result, I am very pleased with how it has turned out. I re-ran the diagnostics, rechecked the keyboard etc and all looks good.

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I have a couple of upgrades in the works for this one. Firstly I have installed an A501 RAM expansion, this actually came out of the other 500 (more on that RAM expansion to come in another thread, it involved a Varta battery). For display I purchased a Retro Computer Shack RGB SCART cable.

In the post I have a DF0 / DF1 switcher to allow booting from an external floppy drive, I decided to keep the internal drive, I much prefer the look over a Gotek, even the more discreet ones. I intend to run a Gotek externally for loading self booting games as DF0 or use as DF1 to allow me to save my work when carrying out productivity tasks with Workbench or whatever programme I'm using loaded from the internal floppy drive. Note when the external drive is switched to DF0 the internal drive gets disabled, hence me still intending to load Workbench etc from the internal drive when I want multiple drives available to cut down on disk swapping. This might sound like a bit of a faff but I'm happy enough with that solution for now, bear in mind I'm building my A1200 Checkmate project which will be my 'big box' Amiga with Compact Flash drive and the other niceties of that platform.

I'm also weighing up buying a USB mouse adapter, anyone used one or have a particular recommendation for one of these?

That's about it for now, more to follow soon. I'm planning to try and spend some time with this particular Amiga now so will report back some of the stuff I'm doing with it as I go. Restoring these machines can be a hobby in itself, sometimes you forget to get involved and use them. I'll leave you with a game of Lemmings:

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chrisns

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Very impressive & detailed post, @CosmicCruncher ! Thanks for sharing. Particularly impressed with the practicality of your case repair.

Like yourself, I'll be doing some QoL improvements to my own A500, including DF0/DF1 selector and Gotek and also need to diagnose and fix the keyboard issues. Optical mouse via USB adapter also a great idea for day-to-day use.

Any thoughts on a non-destructive location to mount the boot selector switch?
 

CosmicCruncher

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Very impressive & detailed post, @CosmicCruncher ! Thanks for sharing. Particularly impressed with the practicality of your case repair.

Like yourself, I'll be doing some QoL improvements to my own A500, including DF0/DF1 selector and Gotek and also need to diagnose and fix the keyboard issues. Optical mouse via USB adapter also a great idea for day-to-day use.

Any thoughts on a non-destructive location to mount the boot selector switch?
For non destructive I’ve yet to come up with a location. There was someone who has an internal gotek that fed the switch pcb through the floppy eject button hole. If keeping the internal drive I don’t think this is viable though. The other way I can think of is find a way to route the cable out and affix the switch somewhere outside the case.

For my Amiga above, as the case is already imperfect I’m actually planning to drill a hole in the rear of the case near the floppy drive. This should be discreet once installed and can only be seen from the rear of the case. Like you though if the case was pristine as my other 500 is I would be much more reluctant to drill in to it.
 

Retro

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That’s alright, keep ya busy and outta trouble! 😛
 

CosmicCruncher

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Some updates on the Amiga 500.

I mentioned my A501 RAM expansion Varta issues (separate thread still to come for that). I picked up one of those CR2032 replacement boards that go in place of the Varta battery. Soldered that in and I now have a working real time clock. Left the machine unplugged overnight and it seems to have retained the time successfully. Who would have thought in this day and age a real time clock would be so satisfying :D

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Next up I grabbed an external floppy drive off eBay the other day. Worth mentioning this was sold as untested.

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My main interest is in using the drive enclosure for a Gotek while retaining the daisy changing ability, more on that in a second. None the less, I decided to strip the floppy drive itself down and give it a quick head clean. That wasn't so straightforward on this NEC mechanism, not sure if anyone else has taken one of these apart? First thing I noticed was a wayward spring when I removed the drive mech shell that definitely wasn't seated in the right place. I couldn't readily see where it has come from and it doesn't seem to affect the drive operation, so have put that to one side to tackle another day. Reassembly went ok and I took the opportunity to install some new cork feet. It came with a single rubber foot which wasn't ideal.

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Another annoyance, the drive was shipped in a jiffy bag with no extra padding so I've ended up with a smashed DB23 connector housing.

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The connector itself is fine so I might try and bodge this one with some epoxy to stop it getting worst and keep and eye out for a replacement housing. Don't suppose anyone has one spare?

I then gave the drive a full test, there does seem to be an issue with the write protect sensor. Sometimes when writing / formatting a disk it will say it's write protected. Removing and reinserting the disk seems to clear it so I think the switch may just be a little dirty. One thing I will say is this particular drive is whisper quiet compared to the internal Amiga drive. Almost a shame I likely won't be using the drive mech day to day.

So, on that Gotek conversion, I forgot to take a photo but on the NEC mechanism the 34pin connector is in the top left rear corner of the drive if looking from behind. The female connector in the enclosure is mounted on a PCB in a fixed position for the NEC drive which doesn't leave much tolerance to accommodate the connector in a different place, I think it's more central and lower down on a Gotek. I don't have a Gotek to do a trial fit yet but I think the way forward will be to make up a short floppy drive cable to go between the Gotek and the enclosure PCB. I'm hoping this will do the trick.

My final upgrade endeavour was less successful. My DF0 / DF1 drive selector arrived from Amiga Kit. Unfortunately on attempting to install it in to the CIA socket on the A500, it went about half way and needed a fair amount of force but wasn't sitting right. A small nudge to the edge of the PCB and it popped out of the socket, I wasn't happy with this, I can see it popping out at random when I transport the machine. @RobA1200 warned me of this as he had the issue as well, it's because the selector has round pins which don't sit well in a socket designed for flat pins. @chrisns You may hit this issue with yours, would be interested to know how you get on. I've emailed Amiga Kit so will see what they suggest. I think there are some versions of the selector out there with different pins.
 

Retro

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That drive selector popping out looks like a design issue and an unacceptable one at that. Is it possible to buy an alternative product?
 

CosmicCruncher

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That drive selector popping out looks like a design issue and an unacceptable one at that. Is it possible to buy an alternative product?
There are a number on the market that all follow a similar design. There is a thread here http://eab.abime.net/showthread.php?t=97506, someone else with the issue got their problem resolved by Amiga Kit so I'm hopeful. I think some of the problem is the various components used by Commodore even across boards of the same revision. I will report back how it goes.
 

Retro

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There are a number on the market that all follow a similar design. There is a thread here http://eab.abime.net/showthread.php?t=97506, someone else with the issue got their problem resolved by Amiga Kit so I'm hopeful. I think some of the problem is the various components used by Commodore even across boards of the same revision. I will report back how it goes.
Yes, mfrs do sometimes change the internal specs a bit as production runs continue to make things cheaper, or improve in some way, while leaving the model number identical to what it was before. Can be a bit of a PITA, too.

According to some article that I read a couple of years ago, monitor mfrs are notorious for this. They release a new model with a great display panel and get great reviews. Some time later, they quietly change to an inferior panel to save on costs, while keeping the model number the same, but in the meantime, the customer is mislead by the good review which is for effectively a different product. Looks like in the main they never realise the deception either, so the mfr gets away with it.

I've got direct experience of this, too. About a decade ago, my workplace bought a set of Iiyama monitors. These were 26" 1920 x1200 screens. Lovely picture and judging by the viewing angles and colour saturation, these were IPS panels.

About a year later, I buy the exact same model and guess what? It's clearly a TN panel, with all the viewing angle and colour issues. I wasn't happy, but kept it as it was still a great monitor and love that 16x10 ratio. Indeed, I still have it although it's not been used for years now.
 

CosmicCruncher

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Quick update on the drive selector, I’m still waiting for a response from Amiga kit. In the meantime I’ve started stripping down and cleaning the A500 Plus (upcoming thread for that one 😉). Thought I would give the drive selector a go in it, what do you know, it’s a perfect fit and tested ok.

The socket on the board did look slightly different so I think the problem I had was definitely down to socket design.

I’m going to leave that one in the 500 Plus now but will continue to try and get a resolution for the 500 above.
 
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