exxos's Atari, Amiga & retro forum

friijy2001 wrote: 11 Jun 2021 10:40 Another screen over RGB scart just to add to the library :)
This is static but sometimes it rolls

So that TV works fine all the time other than the rolling ?

exxos wrote: 11 Jun 2021 11:05

friijy2001 wrote: 11 Jun 2021 10:40 Another screen over RGB scart just to add to the library :)
This is static but sometimes it rolls

So that TV works fine all the time other than the rolling ?

That’s just one screen shot, it sometimes goes black and says no signal, sometimes it’s fine.

It works fine on other st’s

What PSU u got in there ?

I had similar issues with Toshiba LCD TV, and a SCART cable, which was making RGB switching voltage from the V-Sync, using a diode and a capacitor.

exxos wrote: 11 Jun 2021 13:11 What PSU u got in there ?

Have tried it with a phisong (not sure if that’s the correct spelling) and also a mitsumi

friijy2001 wrote: 11 Jun 2021 13:23 Have tried it with a phisong (not sure if that’s the correct spelling) and also a mitsumi

If you have a SR98, you can try upping the 5V to maybe 5.5V (for a short time) just to see if it helps or not. Just be voltages on that particular machine or just marginally too low for your monitor to be happy.. So upping the 5 V may or may not give a indication for that problem..

I'll try the chip under the PSU first and see where that gets me after work, I'll report back and see where we are then.

OK a quick update,

• I did the reset switch fix and no change

• I pulled the chip from under the PSU out, luckily I have a donor chip so replaced it and it has seemed to be working...

The old chip

C300588-001 Atari 1988

New chip from the donor board - C301712 Atari 1990


Running without the shielding and case it seems to work fine after numerous reset's and power off/on


I will pop the case back together and continue testing :)

friijy2001 wrote: 11 Jun 2021 16:04 I will pop the case back together and continue testing :)

I guess it would be interesting if you put the old chip back in to see if the fault returns..It could be a bad connection, but I have noticed a different part number on the chip as well..

exxos wrote: 11 Jun 2021 16:12

friijy2001 wrote: 11 Jun 2021 16:04 I will pop the case back together and continue testing :)

I guess it would be interesting if you put the old chip back in to see if the fault returns..It could be a bad connection, but I have noticed a different part number on the chip as well..

Yes it was a little bit of let's see what happens going :lol: . I am going to test it with the other chip for some hours to see what happens and will plug the old chip in to see it it was a bad connection or the chip at fault.