Se/30 video issue

[bibilit]

New caps all around and new UE8 (LS166)

the pointer is there and I can move it around, the flashing folder is present. 

Any idea ?

 

[Bolle]

That’s most probably a problem with the VRAM address muxes (UA8-UD8).

Either one of them is bad, you got a broken address line to them or there’s still cap goo sitting around/under one of them.

 

[bibilit]

Thanks Bolle. 

All of them were removed and replaced, cleaned underneath. 

 checking address lines is next move. 

 

[Bolle]

You replaced them with F253s I suppose?

Using a different type is like asking for trouble.

Start with the low address lines, usually A0 or A1 are broken.

 

[bibilit]

Yes F253s

More to follow...

 

[bibilit]

@Bolle

your hunch was right. 

A0 was broken. 

 

[bibilit]

Another trace was broken, in the SCSI area. 

Working fine now. 

 

[ttb]

For what it's worth I had a couple of bad traces to the SCSI IC on two of mine. I tried running the bodge wires on the bottom of the board like you did there (to keep it neat looking), but while it fixed the issue, the machine was unreliable and would eventually stop working after running for a bit. @techknight counseled me that since it's likely a bad via I really need to run the wires topside. I haven't gone back to that board with any intensity, but if you find any issues after it warms up that might be worth looking into.

 

[bibilit]

i have been using thick wire here, pushing it through the via hole, so far so good.