Search found 42 matches

by displaced
Tue Jan 26, 2021 9:20 pm
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

BTW if that PSU is better, have you tried moving it closer to the motherboard ? Also wondering if the video is picking up interference from the PSU.. and as you have the meanwell "out" of the way... was just a thought anyway.. I didn’t try this I’m afraid - got caught up in other stuff. B...
by displaced
Thu Jan 07, 2021 3:46 pm
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

Yeah - don’t know why I didn’t just go for it. Always seems like a big job for amateurs like me. But I’ve done it once before on an Archimedes, and have replaced caps elsewhere with success. And PSU caps are usually nice and chunky on not especially dense PCBs - so not technically difficult, just ne...
by displaced
Thu Jan 07, 2021 3:18 pm
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

So just to wrap up from my side: Have swapped back to the old PSU and the noise has immediately returned. Have ordered exxos’s recap kit for my model PSU, and I’ll keep the Meanwell as a nice multi-volt test supply. I’ve got a bare STE board I can use it on for tinkering. Thanks all for your help - ...
by displaced
Thu Jan 07, 2021 12:31 am
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

Ah no, I hadn't -- I did post some scope traces from the existing one that didn't look too bad early on. Should've bit the bullet and done that straight away, but the voltages were good and the machine was stable. I think geogeo_28, with almost identical interference, had recapped their PSU and moth...
by displaced
Thu Jan 07, 2021 12:08 am
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

Well, whaddya know... Wired up a Meanwell RQ85B, and here's the output (earth connected, OSSC powered via its usual USB adapter). IMG_5889.JPG Still a little bloom-y, but the interference pattern's gone. There are still slight jailbars visible, but they're barely visible from a normal viewing distan...
by displaced
Wed Jan 06, 2021 4:46 pm
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

Some of that might be my phone - it’s quite difficult to get a good picture of the screen. Had to force focus on a dark area to get it to show the interference. It looks bright, but not bloom-y in real life. Plus, this is my usual computer monitor which is normally used with my PC. I’m a bit of a b’...
by displaced
Wed Jan 06, 2021 10:51 am
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

That’s about right for Xenon 2 - the regularity and strength of the pattern varies. I’ll fire up I, Ball later for a direct comparison to before.

Very odd!
by displaced
Wed Jan 06, 2021 9:19 am
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

Well, poo.

Running the OSSC via battery doesn’t help. Had a good feelinng on that one, too.
6DE75F6C-AAAF-4AEA-B155-F89967C4D3A5.jpeg
6DE75F6C-AAAF-4AEA-B155-F89967C4D3A5.jpeg (203.3 KiB) Viewed 3151 times
by displaced
Wed Jan 06, 2021 1:20 am
Forum: HARDWARE ISSUES
Topic: 68HC000 (and other MSTE CPU) oddness
Replies: 3
Views: 1798

Re: 68HC000 (and other MSTE CPU) oddness

Thanks for the info -- these things really were pretty much barely working even from new, weren't they? :lol:

I'll find out what I need to know about swapping those pullups!
by displaced
Wed Jan 06, 2021 1:15 am
Forum: HARDWARE ISSUES
Topic: MegaSTE Repair Continued - Video Noise
Replies: 69
Views: 22439

Re: MegaSTE Repair Continued - Video Noise

I've had a voice at the back of my mind whispering 'grounding'... I'll disconnect the earth temporarily on the PSU when I get a chance tomorrow! I found that I could mostly hide the problem by reducing the OSSC's Pre-ADC Gain from 8 to 0, but then the overall picture was unnaturally dim. I used a .P...

Go to advanced search