exxos's Atari, Amiga & retro forum

Hi all,
I have acquired an old Atari STFM which initially had no power at all- took a bit of advice and fitted a new centuriontech PSU, and we are up and running. The issue I have now is minor but annoying - using either RF cable, a RGB->SCART cable or a RGB->Composite cable, I'm getting a) ghosting and b) wobbliness. To elaborate on the wobbling, it's an oscillating wave - pixels move from side to side gently, maybe only moving by 0.5 pixels or so. This happens on both my CRTs and whereas it's not so terrible that low-res games are unplayable, it's very noticable in GEM and makes it hard to read or do anything in medium res.

I've seen the video recap kit on the exxos shop, is that likely to fix it? If not, any ideas please?

The phone camera doesn't do it justice but here's a picture of the ghosting. In real life it looks worse... you can see the mid-wobble on the right-hand side too - I can't persuade the camera to take good video of the screen but imagine that wobbling gently!


Cheers
Tom

Out of curiosity, do you have another machine with a standard PSU, or a bench PSU?

The ST will run on just 5v, so I'd be tempted to hook it up to a bench PSU if you have one and see if the problem is still there. If not, what options do you have for testing with a different PSU?

rubber_jonnie wrote: 11 Jan 2024 23:02 The ST will run on just 5v

I believe that the connection to SCART needs a little bit of 12V so that the TV knows that there is a device connected. It's pin 8 of the video port.

sporniket wrote: 13 Jan 2024 06:27

rubber_jonnie wrote: 11 Jan 2024 23:02 The ST will run on just 5v

I believe that the connection to SCART needs a little bit of 12V so that the TV knows that there is a device connected. It's pin 8 of the video port.

From what I read, it isn't mandatory to have 12v for SCART to work, but it's a good point.

However I'd still want to test with a different PSU at just 5v as the OP does suggest the problem occurs on all video types (RF, RGB, Composite, SCART), because I've run into issues with PSUs causing screen wobble (My OSSC needed a replacement PSU due to wobble/Interference) and it'd at least rule it out and they can use a non-SCART cable.

If the problem still occurs with a different PSU, then at least the troubleshooting can move to the next step.