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| Click here to select a new forum. | | SE/30 video problem: groups of scanlines being displayed twice | Posted by: dontdoxmeman on 2020-01-27 23:54:52
Finally graduated from lurking, and I'm hoping for some repair advice. My SE/30 is showing scanlines repeated and flickering. Has anyone encountered this before?
I took a video, you can see it on reddit:
| Posted by: Bolle on 2020-01-28 01:57:25
I had something that looked similar on one of my SE/30 logicboards. It was due to a trace that barely made contact to a solderpad on one of the VRAM address muxes.
It could also be that one of the muxes is faulty and has a weak output or dead inputs. The video data shift register at UE8 could be another possible cause.
Can you take a screenshot and see if the lines appear on the picture as well?
Has your logicboard been cleaned and recapped already?
That's the first thing you should always do (or get done by someone) before any further troubleshooting takes place.
| Posted by: bibilit on 2020-01-28 02:25:51
I agree with Bolle, can also be fluid coming from capacitors shorting legs somewhere.
| Posted by: dontdoxmeman on 2020-01-29 01:02:18
I haven’t recapped it yet. Obviously needs it, being 30 years old, and the audio is very faint which is a telltale sign at least those caps are dying. Tonight I took it all apart, saw a little bit of oxidation/possible corrosion on some SMT chip pins around the video area of the motherboard. Traces still look quite good though, no obvious capacitor juice anywhere. Tossed the dead lithium battery timebomb, did some quick cleaning with isopropanol and put a little deoxit on some of the more corroded chip legs. Analog board looks pretty immaculate, didn’t do anything to it yet. Reseated the simms and left the second bank of ram out this time.
Connected it back together and turned it on, and already saw quite a bit of improvement! The heavy flickering is still there and quite variable, but I’m not seeing nearly as many repeated or missing scanlines. However, after leaving it on for a few minutes it got a little bit worse again (though still not as bad as before).
I’m pretty optimistic now that a recap will fix this. Will update whenever I get that done.
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