Mac Se/30 logic board, video problem

[antonio66]

Dear,

I bought an old SE/30 for server-purposes, but sadly it has a video problem. I see only a fine horizontal line. The vertical sweep circuit on the analog board doesn't work, but all parts on the analog board are ok.

We detect the problem on the logical board. The UI6 (341-0665-A) seems to be defect, because there is no trigger on pin 4.

It is a PAL16R4B; must they be programmed bevore replacement ?

thx

antonio

 

[Brooklyn]

Check out this site if you haven't already:

http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html#SimasiMac

 

[antonio66]

Hej,

I know the site. I first replaced the mentioned caps and the TDA1170, but no difference. Then I recaped the logic board, and my colleague gauge "no trigger" signal on UE6.

no chance... and no idea

 

[8bitbubsy]

A single horizontal/vertical line is usually because of some dried up solder on the analog board, especially on one of the CRT connectors -- did you check for any dried/black looking/cracked solder points?

 

[antonio66]

Yes, I did. I solder them new and bend (a little) the connectors, too.

Thats not the problem; I could measure nothing on the vertical line. So I check back to the next cap, TDA1170 and so on. My colleague has a ascilloscope and he check back until pin 4 from the UE6 on the logic board.