A visually impaired duo - VIC-20 and Atari 600XL

[stephen_usher]

Hmm. It's a bit hard to see in that video.

The coloured jail bars on my C64 aren't :-)

2022033108114565.png

[rubber_jonnie]

Hmm. It's a bit hard to see in that video.

The coloured jail bars on my C64 aren't :-)
2022033108114565.png

Yeah, I may try to get another vid, IIRC it is worse if I push it through the OSSC. Can see your jailbars, I think there are a few C64 solutions for that.

[rubber_jonnie]

Woo hoo, my replacement VIC has shipped :)

[stephen_usher]

Yeah, I may try to get another vid, IIRC it is worse if I push it through the OSSC. Can see your jailbars, I think there are a few C64 solutions for that.

Indeed. There's LumaFix64 and another one, but they're only for the luma signal and not the chroma.

[rubber_jonnie]

Yeah, I may try to get another vid, IIRC it is worse if I push it through the OSSC. Can see your jailbars, I think there are a few C64 solutions for that.

Indeed. There's LumaFix64 and another one, but they're only for the luma signal and not the chroma.

Just realised, your C64 seems very purple, I'm going to have to check mine now.

[stephen_usher]

I think that may be the capture device. it doesn't look that purple on the screen, though there is a hint.

[rubber_jonnie]

I think that may be the capture device. it doesn't look that purple on the screen, though there is a hint.

Fair enough :)

[rubber_jonnie]

Once I'd got as far as I could with the Dragon today, I picked back up on the Atari 600XL shimmery screen.

Since there was never any problem with the VBXL in the 800XL, and completely ruled out the PSU and TV, I figured there must be interference due to the more cramped internals, after all the 600XL is about half the depth of an 800XL.

As it happened I'd removed the shield from the VIC-20, which is cardboard with metal foil on one side, so I thought it was worth a try to put a piece between the VBXL and the mainboard.

So I rigged up this:

PXL_20220402_133509342.jpg

It sits between the VBXL and the logic ICs on the mainboard, and I used a clip lead to ensure it was grounded. And wow, the shimmer is so reduced it's now totally usable!!

All I need to do now is rig it up permanently and I can close the machine up again :)

Happy days, that just leaves the VIC-20 to fix, and the replacement VIC is in the post, so fingers crossed it'll soon be back to itself again too.

[rubber_jonnie]

Dammit, I've jumped the gun. If left long enough, the shimmer comes back, which is SUPER annoying. GRRRR

[stephen_usher]

Yeah, welcome to the wonderful world of analogue pain. :-)

Similarly on my C64 the colour banding gets worse as the machine warms up.

Both are probably due to some sort of resonance somewhere that drifting components hit when they both drift to when they're warm.