SE/30 - black screen

[VicNor]

Introduction​

So I’ve bought a known defect SE/30. I got it for about €70 with the carrying bag, some documentation and original (and blank) floppies. An over all OK deal. It was known from the listing that the screen was black. When I started the computer for the first time the screen was black and there was no chime, but the computer booted from the hard drive as if there was no problem (Bare bone install of System 6.0.7 so the total boot time is 17 s from turn on).

What I've done so far​

I cleaned the electrolyte salts from the motherboard with some isopropanol and a wet toothbrush and after spraying with compressed air and over night drying I tried the board again. This time I got a faint chime from the speaker, when I flipped the ON-switch then the computer proceeded to boot as normal. Also, there was a lot of bubbles under the U8 row (memory muxers, I believe) and the two SONY sound chips, but I got rid of the cap juice to the degree that it didn’t bubble when I brush.

[Photos show cleaned logic board: U8 row, SONY sound chips and the board in its entirity]



In my collection I also got a working SE in very good condition, so I’ve swapped out the logic boards! There appears to be nothing wrong with the power supply or analog board on the SE/30 when I plug in the SE logic board. The screen on the SE/30 got some burn in from the menu bar, tho. However, with the SE/30 logic board in the SE I can see “something” on the screen – patches/blotches of ever so slightly brighter areas, as if the signal is too weak to make the phosphor react.

[Photo shows SE logic board working with the SE/30 analog board and power supply]

Thoughts and suggestions​

I watched the entirety of Branchus Creations trouble shooting of Javier’s SE/30, and the follow-up video. Especially in the follow-up video it’s mentioned that the sound can’t work without proper caps, but that the video should work even without any caps installed.


I’ve got new caps ordered and a friend will help with the recapping and he has an ultrasonic bath. Should I hope for that the ultrasonic bath will just fix the video signal? Given that the video shouldn’t need any caps to work, where focus my continued trouble shooting at?

 

[fred1212]

You need to change the caps wether you ultrasonic clean or not and the battery

 

[fred1212]

I'd be happy at 70 pounds

 

[YMK]

Those yellow band caps are bad news. You'll have to pull them to inspect the traces underneath.

 

[VicNor]

Those yellow band caps are bad news. You'll have to pull them to inspect the traces underneath.

You're probably right that I need to remove the old caps first before I can completely trouble shoot the board. But I would prefer to get the video working before putting the new caps in - or it'll be even harder to pin point the problem.

I did another brush yesterday with the toothbrush and acetic acid ("vinegar") and there were still a lot of bubbling under the U8 row. It still didn't show any video when testing (after I washed up the board and let it dry). I can't rule out trace damage at this point. I wish that I had the schematics for the logic board that Mr Bruce had access to in his repair stream. It would surely help a lot.

My new flux won't arrive until sometime next week, so non-invasive measures are my only option at this point.

 

[MacOfAllTrades]

Introduction​

So I’ve bought a known defect SE/30. I got it for about €70 with the carrying bag, some documentation and original (and blank) floppies. An over all OK deal. It was known from the listing that the screen was black. When I started the computer for the first time the screen was black and there was no chime, but the computer booted from the hard drive as if there was no problem (Bare bone install of System 6.0.7 so the total boot time is 17 s from turn on).

What I've done so far​

I cleaned the electrolyte salts from the motherboard with some isopropanol and a wet toothbrush and after spraying with compressed air and over night drying I tried the board again. This time I got a faint chime from the speaker, when I flipped the ON-switch then the computer proceeded to boot as normal. Also, there was a lot of bubbles under the U8 row (memory muxers, I believe) and the two SONY sound chips, but I got rid of the cap juice to the degree that it didn’t bubble when I brush.

[Photos show cleaned logic board: U8 row, SONY sound chips and the board in its entirity]
View attachment 9121 View attachment 9122
View attachment 9123

In my collection I also got a working SE in very good condition, so I’ve swapped out the logic boards! There appears to be nothing wrong with the power supply or analog board on the SE/30 when I plug in the SE logic board. The screen on the SE/30 got some burn in from the menu bar, tho. However, with the SE/30 logic board in the SE I can see “something” on the screen – patches/blotches of ever so slightly brighter areas, as if the signal is too weak to make the phosphor react.

[Photo shows SE logic board working with the SE/30 analog board and power supply]
View attachment 9124

Thoughts and suggestions​

I watched the entirety of Branchus Creations trouble shooting of Javier’s SE/30, and the follow-up video. Especially in the follow-up video it’s mentioned that the sound can’t work without proper caps, but that the video should work even without any caps installed.


I’ve got new caps ordered and a friend will help with the recapping and he has an ultrasonic bath. Should I hope for that the ultrasonic bath will just fix the video signal? Given that the video shouldn’t need any caps to work, where focus my continued trouble shooting at?

Photo of what shows on the SE with the se/30 board plz!?

 

[MacOfAllTrades]

You're probably right that I need to remove the old caps first before I can completely trouble shoot the board. But I would prefer to get the video working before putting the new caps in - or it'll be even harder to pin point the problem.

I did another brush yesterday with the toothbrush and acetic acid ("vinegar") and there were still a lot of bubbling under the U8 row. It still didn't show any video when testing (after I washed up the board and let it dry). I can't rule out trace damage at this point. I wish that I had the schematics for the logic board that Mr Bruce had access to in his repair stream. It would surely help a lot.

My new flux won't arrive until sometime next week, so non-invasive measures are my only option at this point.

https://museo.freaknet.org/gallery/apple/stuff/mac/andreas.kann/schemat.html

try this. See the video schematic as it has your muxes. Post pic of what your se30 board in the se shows on screen.

 

[VicNor]

Photo of what shows on the SE with the se/30 board plz!?

It's not much to see. It's just a black screen and an external harddrive that blinks away while the computer is booting. I thought it was more important/relevant to show that the analog board is still working in the SE/30.

Also, I believe that the GIF's that you linked to are the same as this redrawing. At least it seems to match while I compare them.

GitHub - mishimasensei/macse30mlb: Macintosh SE/30 Main Logic Board Schematic Drawings

Macintosh SE/30 Main Logic Board Schematic Drawings - mishimasensei/macse30mlb

github.com

 

[pfuentes69]

Replacing the UE8, UF8 could be required... these trend to die due to the cap goo... UD8 and UG8 could be affected, but I think is not that common.

On my SE/30 I had a horizontal line. The Mac was booting fine like yours, but I only got it right after replacing those ICs

 

[MacOfAllTrades]

Replacing the UE8, UF8 could be required... these trend to die due to the cap goo... UD8 and UG8 could be affected, but I think is not that common.

On my SE/30 I had a horizontal line. The Mac was booting fine like yours, but I only got it right after replacing those ICs

I was going to suggest reflowing the solder pins on all of the muxes if OP felt comfortable doing that. It’s not too hard and it could help. But yes replacing the muxes may be necessary.
Really I think the recap is step 1.