Updates and some Smaller Projects

Well I haven’t stopped working on projects and while some of the have been successful, others have not been so successful. It doesn’t help that my desoldering station has broken. I just need to get some specialised glue to fix it.

Archimedes

The Archie still has a bunged Floppy Disk Drive and I’m stumped as to what the problem could be. I’ve traced every wire from the FDD to the the chips they connect to. I have then checked from those chips to either the bus or to the next chip. I have also checked those chips. I’ve run out of ideas as to what to look at next. Back in the naughty corner with it for now. It’s a pity. I’d love to have it working well enough that I could use it. I even have upgrades for it that are just sitting around as I can’t use them.

Testing all the connections. They all passed.

Commodore 64

I have a C64 that’s dead. Black screen. The Dead Test cart flashes once. That usually indicates the first bank of RAM. I’ve swapped that RAM with known good RAM. No change. I’ve swapped the PLA. No change. I probably need to get it under an Oscilloscope. This brings me to my next point.

Essential for debugging Commodore 64s

BitScope Oscilloscope.

I’ve hit the limits of what I can do with this scope. The big limitation is the lack of documentation. The website links only to a defunct video. Not the most helpful. I think I’ll need to get a new ‘scope.

Amiga MultiKick

I tried upgrading the ROM set on my 4 ROM Amiga MultiKick. I’m using an adapter in my TL866II+ to allow me to burn larger ROMs, in sections. It works well, but I haven’t been able to get Kickstart 2 to work. Normally it would just be a matter of reversing the byte order and burning it out. It shows up in the TL866 and looks sane. I just get the screen flashing red. The other 3 ROMs work fine. I even went out to see if there was a different version of the ROM and there’s not. I’m even using the official ROM from Cloanto that came with Amiga Forever when I purchased it.

This came with Kickstart 1.3, 3.1, 3.2 and DiagROM. I don’t need 3.2 on this system, and I don’t have a license for it. I’m trying to get Kickstart 2.05.

1081 CRT Monitor

This came with the Amiga 2000 and was reported as having a dead Monitor switch. Thankfully replacements are available and I even had some in stock. It was a relatively pain free job to crack the cover, remove the switch and solder on a new switch in it’s place. I even added shrinkwrap where the original switch had none. Tested OK with my Amiga. This is my first monitor with SCART.

I’d forgotten how heavy CRTs were.

GBS Control

I’d started this project a long time ago, but finally got it working the way I wanted. Effectively it’s a hack of the GBS8200 arcade scaler to make it more compatible and more stable with a wide range of systems. It consists of the GBS 8200, with an ESP32 development board wired in, as well as an optional high accuracy chip clock generator.
The whole thing is silly cheap to build and the picture quality is astounding. I’m using mine as a flicker fixer for my Amigas.
One of the more interesting things I attempted this time around was to add shielding to unshielded cables. The wires used for the video signal were just straight hookup wire, terminated in the “special” connector for the GBS. I found some old coax, stripped the outer plastic sheath carefully, then removed the copper inner sheath. I then “puffed” this up by compressing it along the direction the sheath ran. I ran the cables I wanted to shield through the middle of the copper sheath then stretched the sheath out over the wires. I terminated both ends with glue impregnated heatshrink to make sure it doesn’t go anywhere.
I don’t know if it’ll actually make a difference, but it sure looks nice.

Left: GBS Control. Right: NecroWare MCE Adapter

NecroWare MCE Adapter

This is a little kit I got made up when I ordered the boards for the Omega MSX. It’s designed to convert TTL level signals like those from an IBM CGA adapter over to VGA style signalling. It’s based around a GAL to do the level shifting. In fact, this was the first GAL I ever programmed! (I programmed an additional 3 for the Omega MSX).
While not advertised as working with the Commodore 128, I thought it was worthwhile to at least attempt to use it with the C128, as I knew the signalling was supposedly the same.
I’m pleased to confirm it worked flawlessly.
I have another Necroware project just pending parts.

Amiga 2000

I’ve started the long, long path of trying to get the Amiga 2000 back on its feet. Step one is getting the power supply sorted. This is proving “exciting” as the existing power supply was not only dead in an exceedingly difficult to fix way, the power supply itself had been mercilessly hacked by a previous owner.
My current plan is to modify an ATX Power supply to work in its place. I’ve modified the old PSU frame to take the new PSU. I just need to wire the Amiga loom to the ATX PSU. I’d like to do it in a way that I can swap out the PSU if needed. I plan to start by attacking an old motherboard for its ATX connector. I’ll need a desoldering station for that.

Someone took to it with tin snips. They just bent over the metal rather than removing it. I’ve bent it straight since.
This blown cap is under a heatsink. In turn power transistors are clamped to it. Their access screws can’t be accessed without desoldering several other components. I gave up.
ATX PSU in the chassis of the dead PSU.

Published by ilike8bits

I collect old computers and consoles

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