The Amiga 600 was in its day the machine nobody really wanted — a final attempt to flog the almost original spec 68000 platform from 1985, in 1992. Sure it had a PCMCIA slot nobody used, and an IDE interface for a laptop hard drive, but it served only to really annoy anyone who’d bought one when a few months later the higher-spec 1200 appeared. It’s had a rehabilitation in recent years though as a retrocomputer, and [LinuxJedi] has a 600 motherboard in need of some attention.
As expected for a machine of its age it can use replacement electrolytic capacitors, and its reset capacitor had bitten the dust. But there’s more to that with one of these machines, as capacitor leakage can damage the filter circuitry surrounding its video encoder chip. Since both video and audio flow through this circuit, there was no composite video to be seen.
The hack comes in removing the original chip rather than attempt the difficult task of replacing the filter, and replacing it with a different Sony chip in the same series. It’s nicely done with a connector in the original footprint, and a small daughterboard. The A600 lives again, but this time it won’t be a disappointment to anyone.
If you want to wallow in some Amiga history as well as read a rant about what went wrong, we have you covered.
LinuxJedi fitted one of these to my A600 about a year ago to fix a twice failed repair by another service and it has been perfect ever since.
Inasmuch as an A600 can be “perfect” – I remember back circa 90-91, walking round my local computer shop and seeing the newly-launched A600, and thinking – even then – “why would I want this? I have an A500 with ECS and KS2.04 already.”
Bought myself an A1200, though, when that came out. And went through an alarming number of very-fragile 2.5″ IDE drives in it :(
I was in the computer shop that day, as I recall, because they had an amazing offer on bargain 3.5″ floppy disks – only £1 each! Bargain! 😂
Stop crying John I was the one that told you about this service in the 1st place but you wouldn’t wait or listen, blame yourself it wasn’t ready and I told you to wait for it to be ready you’re choice not to.
Yet you seam to take opportunity to blame others look in the mirror to see the culprit.
Glad I could help :)
In the new year, I will be selling the mod as a kit for anyone. Really useful for CD32 users, because the same probably kills the S-Video as well as composite and RF.
Noice! Did you [@Linux Jedi] see the thin flex interstitial PCB I did that directly sits between the 1145 footprint and a 1645 chip? I shared it with [@pillock] in the RMC discord (and maybe my GitHub… I’ll have to go check. It should be listed on OSHpark at any rate)
I know he revived a few A600s with it. I never got round to actually doing mine. Maybe I’ll get back to doing Amiga stuff after Christmas…
It was an adapter to CXA2075…
https://oshpark.com/shared_projects/FuaQODGP
Oh and the 1645 very as well (I’m a mess today and OSH search isn’t working for me)
oshpark.com/shared_projects/YnodtpCz
I was going to do something like that, but I wanted the audio buffer to be the same as the 1145, and it ended up growing a bit too large to make that practical. Very cool solution you have there though :)
Also, does your solution replace the current capacitor? There is a bug on A600 boards that causes composite to suck due to that part of their circuit (you can fix it by removing a ceramic cap). I ended up bypass that too in the end and having the capacitor on my board instead.
I honestly can’t remember. It was a while back that I did it. Probably not as it’s just based on the existing schematics floating around for doing the replacement.
nice spotted Jennie!
Not nice to see projects on HaD that have no schematics at least, what’s the point then?
The Amiga 600 schematics were released a very long time ago.
A majority of my CXA fix is public information. A few bits are proprietary based on lots of R&D, it is not yet an open source project (many of my Amiga projects are).