Macintosh IIci - No chime or video after recapping. Any ideas?

[Mac84]

Hello all,

I'm working on a particularly unhappy Macintosh IIci board. After a recap and repair of the startup circuit area, the system turns on (with a green LED on the board), but I don't get a chime. The speaker does "pop". I'm using known-good RAM and the PSU is good as well.

When I turn the system on I get a blank screen, but I do get a colorful (often pink or yellow) flash on the screen once I press the Reset switch on the board.

Oddly enough, the system acts the same whether RAM is installed or not!

Sadly, the bottom of the board (see attached photos) has a LOT going on, although most of the traces appear to map out okay, I'm sure there could be a problem.... somewhere...!

Here's what I've tried:
- Using a ROM SIMM to bypass the built in ROM
- Swapped the three chips by the startup circuit with new chips
- Looking at the board with a thermal camera (nothing stands out)
- Reflowing the ROM pins under the board
- Reflowing the PSU connector under the board
- Cleaning up around the sound chip
- Cleaning up around the startup circuitry
- An ultrasonic bath

Any ideas of chips / areas to pin out or further troubleshooting paths would be great, thanks!

-Steve

 

[Kai Robinson]

Hello all,

I'm working on a particularly unhappy Macintosh IIci board. After a recap and repair of the startup circuit area, the system turns on (with a green LED on the board), but I don't get a chime. The speaker does "pop". I'm using known-good RAM and the PSU is good as well.

When I turn the system on I get a blank screen, but I do get a colorful (often pink or yellow) flash on the screen once I press the Reset switch on the board.

Oddly enough, the system acts the same whether RAM is installed or not!

Sadly, the bottom of the board (see attached photos) has a LOT going on, although most of the traces appear to map out okay, I'm sure there could be a problem.... somewhere...!

Here's what I've tried:
- Using a ROM SIMM to bypass the built in ROM
- Swapped the three chips by the startup circuit with new chips
- Looking at the board with a thermal camera (nothing stands out)
- Reflowing the ROM pins under the board
- Reflowing the PSU connector under the board
- Cleaning up around the sound chip
- Cleaning up around the startup circuitry
- An ultrasonic bath

Any ideas of chips / areas to pin out or further troubleshooting paths would be great, thanks!

-Steve

How hot do the SCSI and SWIM chips get with power on?

 

[Mac84]

How hot do the SCSI and SWIM chips get with power on?

The only chip that got hot (126 F) was UC4 (behind the serial ports). And seeing as the other working IIci is happy without it, I removed it from the problematic system. However that didn’t seem to make much of a change.

It seems the color / pattern I see when pressing the reset button changed without the chip, but it also seems to change randomly.

The attached photos are before / after removal.

 

[Kai Robinson]

Yah - UC4 is one of the 26LS30's - not vital unless you need that serial port. Have you got a spare ADB chip (UA13) or RTC Chip (UK14)? You can grab these off a dead Classic board if needed. I'd be interested to know if you replaced Q2, or measure what voltage it outputs when you apply power to the board.

Check the bus transcievers at UD6, UD7, UJ8 and UJ9 (the 74F245's), check the connections at the MDU (UK11) and check for the bus clocks being present.

That should be enough to go on with for now

 

[Mac84]

Yah - UC4 is one of the 26LS30's - not vital unless you need that serial port. Have you got a spare ADB chip (UA13) or RTC Chip (UK14)? You can grab these off a dead Classic board if needed. I'd be interested to know if you replaced Q2, or measure what voltage it outputs when you apply power to the board.

Check the bus transcievers at UD6, UD7, UJ8 and UJ9 (the 74F245's), check the connections at the MDU (UK11) and check for the bus clocks being present.

That should be enough to go on with for now

Thanks Kai!

Q2 gives me -11.8 V on the middle pin and -5 V on the right pin. This is appears to be the same on the working IIci. I will however check on everything else you suggested too, thanks!

Update: Swapping the RTC didn't change anything. Swapping the ADB chip didn't change much, the only difference is now when I press the Reset button, the pattern is a solid color, not distorted like it used to be. But I'll continue!

Can you describe a way to check the clock on (I assume you meant UJ6/7 + UJ8/9) without an oscilloscope ?

 

[Garrett]

Hi Steve, I'm fighting almost the same problem: https://tinkerdifferent.com/threads/another-iici-thread-no-video.2730/

I'll let you know if I solve anything on my end. My board does chime, but all other symptoms you mentioned are happening with this one as well.

 

[Willj]

Thanks Kai!

Q2 gives me -11.8 V on the middle pin and -5 V on the right pin. This is appears to be the same on the working IIci. I will however check on everything else you suggested too, thanks!

Update: Swapping the RTC didn't change anything. Swapping the ADB chip didn't change much, the only difference is now when I press the Reset button, the pattern is a solid color, not distorted like it used to be. But I'll continue!

Can you describe a way to check the clock on (I assume you meant UJ6/7 + UJ8/9) without an oscilloscope ?

Steve, did you ever get this issue solved as I have a board doing the same thing???

 

[Mac84]

Sadly no, due to the horrible condition of the bottom of the board, I simply assume there is some trace not connecting somewhere.

 

[reallyrandy]

I'm having the exact same problem. I have 2 LCIIs I'm working on. One is not recapped and boots fine, the other one was leaking so I didn't try to boot it before recapping. After cleaning the board and recapping and cleaning again, I get no chime and black screen. The fan runs and I can hear the hard drive working. I swapped in the known good board and it boots fine so I know it's not the RAM, ROM, PSU, or drive. I had recapped both PSUs last year. I tested continuity on all the caps that were replaced to their next via or closest chip leg and they're all fine so no broken traces. Attaching several pics at different angles, hoping someone sees something I don't see. I'm hoping I didn't get C10 and C22 backwards. From the markings I couldn't tell which was the 1uF or the 100uF.

 

[fred1212]

I had similar problems with IIci board, it was semi working but only on bank A of memory sometimes. I recapped it and cleaned it and then no video and chime or no video and chime for bad memory.. The board looked very clean and I could find nothing obvious. apart from cap goo UB13,UD13, UE13 which were removed and area cleaned. Gave up and recently sent it to Will at Caymac, he spent a lot of time trying to find the problem and found a lot of trace damage under a number of areas of the solder mask that could only be seen with high magnification. I decide on a reloaded board and am very happy with my now working IIci thanks to Wills expertise.

 

[JDW]

@fred1212
Glad to hear your machine is up and working. Doing those SMD solder job Reloaded boards is no small task, so I can see why Will is currently the only guy out there doing them. It's going to be a sad day for many when and if he stops, assuming no experienced and reliable person is willing to pick up the torch and provide the same service at a realistic price. Let's face it, most people don't want to do that work themselves. Indeed, I highly doubt the average hobbyist could do it. I myself wouldn't want to do an SMD build like that.

Anyway, kudos on the brand spanking new IIci board, Fred!

 

[fred1212]

Yes JDW, Wills' videos on the SE/30 and IIci reloaded are master classes in the art. I would not have been able to do anything like he can accomplish. The repair video on me SE reloaded board just showed me how much I have to learn. Caymac returned boards that had me stumped back to the land of the living thankfully.

 

[Willj]

Thank you both for the support and kind words. I do enjoy the reloaded boards and for now, will continue. Even adding more of them. Keeps me challenged and I enjoy the end results.