• Hello MLAers! We've re-enabled auto-approval for accounts. If you are still waiting on account approval, please check this thread for more information.

Re-capped board, issues remain. Ideas?

zcoffin

6502
I've got this SE/30 logic board that I re-capped today and it's still having some issues, would be curious if anyone has any troubleshooting tips for areas I should look at next.

1. No sound - no boot chime, etc. I haven't exhaustively tested this, however I suspect there's some sneaky issue on the logic board. The internal speaker is definitely connected, but I haven't swapped in my good board to verify the speaker is good. haven't tried the audio output jack yet... I'd be surprised if the speaker is bad, but I guess stranger things have happened. edit: maybe the old caps leaked under the sound chip and it needs to be removed, cleaned, and put back?

2. 1 out of every 8 vertical lines of pixels is dark. (see picture)

Both of these issues existed before the re-cap; I was really hoping I would get lucky and be done with the repairs at this point. After reading the repair guides I'm going to go looking for a short or a broken trace around the audio connector, and try different RAM chips to see if it effects the video in any way. I find it curious that the machine boots and recognizes all of the RAM but still shows the vertical line failure...

I've got three other SE/30 boards - one fully functioning logic board that I re-capped a few years back, one board that works except no sound, and one that has some serious corrosion problems, so if I need to use one as a donor or test with parts from the good one those are some possibilities!

Cheers!

2020-12-13 23.03.13.jpg

 
Last edited by a moderator:
Fixed the bad video line(s), good call! Huge shout out to the maintainers of the re-built schematic files at https://github.com/mishimasensei/macse30mlb; they came in super helpful! I'm guessing that corrosion from the cap that I replaced had damaged the traces under that chip. I guess I won't get away with a short little solder bridge for this broken trace... Only one line was out when first powered on, but after a few minutes the adjacent line went out as well. Unfortunately (fortunately?) all these traces are top-side, so big ugly top-side bodge wires it is!

Now I'm on to the audio issue. A little more info: the headphone jack works great! And the internal speaker (through the connector wire) measures at 63.5 ohms; so I know that's not open or short... Maybe I'll look into the detection for "is a headphone plugged in" - maybe that's just stuck in the "yes" position. That sounds simple enough.

2020-12-14 21.27.50.jpg

 
Back
Top