Recapped SE/30 - only the mouse pointer appears

[macintosh2002]

Hello everyone,
I was lucky to get another non working SE/30 with pattern screen and ethernet card in it. The seller allowed me to open the case to inspect the LB before purchase. Battery has not leaked, the LB was very dirty (first two pics) with some green stuff on one of the sound chip (3430045B) so I brought this one home, gave it a good cleaning with IPA and recapped the LB.
First turn on I got a screen with mouse pointer, but that's it. No chime (headphone jack), no blinking question mark.
I noticed that UE6, UG6, UI6, UE7, UG7, UH7 and Zilog warms up very quickly - floppy port tells me there is +5.1V and +12.7V, but I'm missing the -12V output.
Can someone point me in the right direction? Where should I lock first? (don't have an oscilloscope...)
Thank you

 

[banshee]

I've had this issue with my SE/30 and in my case it was a bad Z8530 chip.

 

[macintosh2002]

I've had this issue with my SE/30 and in my case it was a bad Z8530 chip.

Thank you, great! I'll give it a try

 

[GRudolf94]

Mouse pointer = machine has already chimed (or thinks it did)
Does the pointer move at all, or does the machine appear to hang? Where did you check for the missing -12V? (if floppy port: SE/30s aren't meant to have -12 there).

Put down the parts cannon - understand the failure first.

 

[croissantking]

I had this issue caused by a bad VIA chip.

 

[macintosh2002]

Mouse pointer = machine has already chimed (or thinks it did)
Does the pointer move at all, or does the machine appear to hang? Where did you check for the missing -12V? (if floppy port: SE/30s aren't meant to have -12 there).

Put down the parts cannon - understand the failure first.

The mouse pointer moves smooth at all on both ports. Yes it was on floppy port... In order to understand the failure, the boot sequence must be known and I don’t. It seems that one of the last step is not completed/missing

 

[GRudolf94]

At least it's not hung, then. Given your lack of chime, and the corrosion it had, I think it's plausible you have trace/via damage, at minimum next to the audio circuit, possibly elsewhere too, which can also be cause for these odd "almost boots but not really" symptoms.

Visually inspecting the board and poking at it with a meter in continuity mode might prove revealing.

 

[croissantking]

Op could also try running applecat

 

[macintosh2002]

I removed and cleaned the SWIM and Z8530 with no improvement. Will go next to sound chip. Thank you

Op could also try running applecat

I am not sure if this points me in the right direction. Maybe I´ll try Applecat later

 

[croissantking]

I removed and cleaned the SWIM and Z8530 with no improvement. Will go next to sound chip. Thank you

I am not sure if this points me in the right direction. Maybe I´ll try Applecat later

I recommend firstly looking at the VIAs and the SCSI chip.

AppleCAT is a useful utility that may help you to narrow down the issue further. Have you come across it before? You connect up two Macs with a serial cable, and you put the ‘unit under test’ into diagnostic mode - essentially you press the interrupt button so that it displays the Sad Mac icon. You can then run the software on the host machine.

 

[LaPorta]

As above, the symptom of no blinking question mark floppy is a SCSI system issue. One can also imagine that in the past, someone hot-plugged a SCSI device. It is always possible. That would necessitate replacing the chip. I would also check all the traces in and out of the SCSI chip if there is not an easy to spot failure.

 

[croissantking]

As above, the symptom of no blinking question mark floppy is a SCSI system issue. One can also imagine that in the past, someone hot-plugged a SCSI device. It is always possible. That would necessitate replacing the chip. I would also check all the traces in and out of the SCSI chip if there is not an easy to spot failure.

This is not for certain. Whilst a problem with the SCSI chip or SCSI bus often causes this symptom where you are stuck on a grey screen with just a mouse cursor, it is not the only possible cause. I had exactly the same issue caused by a damaged VIA chip.

 

[LaPorta]

Yes, but that almost certainly involved the VIA and the SCSI system in some way?

 

[croissantking]

Yes, but that almost certainly involved the VIA and the SCSI system in some way?

Just checked and it was my UK11 that was bad. I see that it has a couple of connections to the SCSI chip (SCSIIRQ, SCSIDRQ) so you may be right. But is it also inconceivable that the machine being held up on a grey screen with a cursor could be related to another type of issue?

 

[LaPorta]

I am sure it is possible (I am absolutely no electronics-minded person at all), I am just going off what is in the Dead Mac Scrolls as to the cause of a gray screen with pointer, no question mark floppy on an SE/30.

 

[macintosh2002]

Thank you for your help @LaPorta and @croissantking I've desoldered and cleaned the SCSI chip, added some PLCC sockets to swap and test with another SCSI chip, but this didn't solve the problem. Next will be the VIAs... Troubleshooting would be much easier with an oscilloscope

 

[jmacz]

Not sure if this will help, but I had a stuck on boot with no chime issue recently on my SE/30 but my machine made further progress into the boot than yours did. I had a very weak/distorted chime after which I had no audio and although the SE/30 would boot into System 6.0.8, it would not boot into System 7+. It hung immediately on the Welcome to Macintosh screen. For me, the issue was a broken trace on the D4 data line between the SCC and the SWIM chips.

Specifically, there's a row of three capacitors next to the J12 connector. Those three are in your picture immediately before this post. A number of data lines run right by those capacitors and they have vias along the way. On my board, capacitor leakage had infiltrated all of those vias and in the case of one, caused enough damage and severed the data line. Visibly the trace looked good. But it lost continuity at the via.

This resulted in no sound as it severed D4 between the ASC / SCC chips and the rest of the logic board, and it resulted in a boot hang for me after the Welcome to Macintosh screen.

You may want to recheck the traces where the old capacitors were, and also check all the vias and ensure they are also good. In my case the traces all looked visibly great but I had not toned out each and every line and via.

Also I noted your comment about -12V. I bought two molex connectors off of Amazon (cheaper on Mouser but not after shipping for a minimum order) and created a 12" extension for the cable running from the analog board to the logic board. This saved so much time as I could just bench test with the logic board sitting outside and be in a better position to check voltages, etc. You should be able to easily check the voltage rails off the J12 connector.

 

[my03]

Hi macintosh2002, following (have the exact same issue with my se/30)

(https://68kmla.org/bb/index.php?thr...d-recap-but-decided-not-to.46864/#post-524503)

 

[y0ssar1an]

Thank you for your help @LaPorta and @croissantking I've desoldered and cleaned the SCSI chip, added some PLCC sockets to swap and test with another SCSI chip, but this didn't solve the problem. Next will be the VIAs... Troubleshooting would be much easier with an oscilloscope

Did you ever get around to checking these VIAs? If so, I'd be keen top know how that went.