SE/30 with jail bars

[vtgearhead]

In an earlier thread I mentioned having replaced the 68030 on my SE/30 with a socket and installing an accelerator. Afterwards I ran it for a week on the bench with no problems. Closed up the case, ran it for another day or two. No problem. Today, this:

The machine is 100% operational aside from the annoying stripes. Does anyone have an inkling of what might be causing the problem?

 

[wottle]

First, I'd recommend changing the title of the post to give people an idea of what you are looking for help with. I saw you post and went to look into my notes to get help, and when I came back, I initially couldn't find you post because the title "Just count on it" didn't provide me context.

Second, I had a similar issue with my SE/30


My problem turned out to be the the UE8 chip. I replaced and video was fixed:

"2023-02-01 Forum on ml68k indicates could be UE8 chip. I removed, and realized it had some pins rotted out. Waiting to replace."
"2023-03-01 Replaced UE8 chip and video worked properly again

So I would check traces in the area, and if the traces seem good, maybe remove the chip and replace.

 

[vtgearhead]

Thanks for the reply! You are correct about the thread title, so I've changed it to something more reasonable. As soon as I have a clear bench again I'll take a close look at UE8.

 

[vtgearhead]

I hate intermittent problems... Took the machine apart and ran the motherboard on the bench using extension cables. The problem appeared initially. While it was showing the jailbars I poked, prodded, knocked, bent the pcb slightly and used freeze spray in the area of UE8. No effect on the bars, not even a flicker. After a few minutes I walked to the other room to grab the schematic diagram. When I returned, you guessed it, problem gone and nothing I've tried will bring it back. The leads on UE8 definitely had some corrosion on them from the formerly-adjacent SMD cap (replaced years ago). Rather than remove the chip I ran flux down both sides, tinned up the tip on my iron and drag-re-soldered both sides. System is back together for a hot soak, but so far it's fine.

If it pops up again I'll replace the shift-register.

 

[wottle]

I hate intermittent problems... Took the machine apart and ran the motherboard on the bench using extension cables. The problem appeared initially. While it was showing the jailbars I poked, prodded, knocked, bent the pcb slightly and used freeze spray in the area of UE8. No effect on the bars, not even a flicker. After a few minutes I walked to the other room to grab the schematic diagram. When I returned, you guessed it, problem gone and nothing I've tried will bring it back. The leads on UE8 definitely had some corrosion on them from the formerly-adjacent SMD cap (replaced years ago). Rather than remove the chip I ran flux down both sides, tinned up the tip on my iron and drag-re-soldered both sides. System is back together for a hot soak, but so far it's fine.

If it pops up again I'll replace the shift-register.

Yeah, my chip didn't look too bad but when I removed it, the legs fell off at the base, making me think the corrosion was worse inside than what I could see. The good news is they are cheap and easily available.

 

[vtgearhead]

Heh - I left the machine on overnight running RAM tests and the jailbars returned. I see a chip replacement in my crystal ball...