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I have used an ultrasonic cleaner that I found on ebay, made in China. Its working fine. During cleaning it was like smoke coming up from the MB under the  RAM chips. Cleaned with distilled water mixed with cleaning fluid. The MB looks like new but unfortunately the MB is not working. Same...

Thank You techknight and sigtau for Your comments. I will try to find a ultrasonic cleaner for a reasonable price. If not it will be the dishwasher..

Yes, I cleaned the board with isopropylalcohol after removing the caps. Cleaned with q-tips with aceton were the caps had been. I have recapped SE/30 boards before and I think this one looked rather good. No battery leaking. No obvious destruction on the traces. But I realize that one should...

I got this Mac IIsi a year ago. Removed the battery and all caps then. Didn´t test it before that. Now I have started to get it working.  All caps are replaced with tantalums, new axial caps. When I turn it on, the fan is working, HD is spinning. The screen is white with no mouse pointer. Only a...

I submerged the board in 99% isopropylalcohol for some hours. then cleaned with a toothbrush, high pressure air and dried for some hours.  I checked the tracing You described, all Ok. The board looks very clean and nice, but its not working . Same error code. Time to replace the RAMs.   I...

Thank You techknight for Your interest in this poor portable. In fact it was a poor picture with some dust on the board. After cleaning its looks like this today Previously I have resoldered that RAM, as the soldering did not looked perfect before. The Connections are OK now and no bridges ...

The board looks like this for the moment. Any suggestions if I should try and replace RAMs from rows A, B, C etc or from 1, 2, 3 ,4?

Yes. this is an old picture. Its now recapped with Kemet size C tantalums. I replaced all the size B tantalums with Kemet size C.

This portable now show the error code 00000082  00000101. I have inspected RAM pins but not found any obvious damage. Resoldered some pins but no help. I have got some new RAM chips and will try a last effort to save it by replacing the RAM chips. Does the error code give any information were...

Aplmak You have solved the problem !! PERFECT. I have measured the capacitance on these new tantalums and one of them is defect. They are marked as 47 uF 16V but one of them (C17) is only 34 uF. Se picture. Exactly as You suspected I have bought these from Hong Kong (Ebay).  I have earlier...

Thanks techknight for Your answer. I will try to reflux as You suggested. How about the IC LTC1040CN , LT1054CN8 and OP20H? Can that be the problem?  They are cheap to buy and can be replaced.

I have now measured the connections between PMGR, VIA and hybrid board on a working portable 5120. This 5120 is working and charging the battery. I have found the same connection on both the working and not working board. Checked two times. Se Pictures.    I suppose that means that there is...

I have checked the traces between VIA and PMGR, the numbers on PMGR refers to pin on VIA. Dont know if I have used the correct pin numbers. se Picture. Also Connection to hybrid board. next step is maybee to measure on a healthy board.

Thank You Macdrone and techknight for advice. When I press reset and NMI button it turns off. When I start from KB its the same result. New symtoms, dont know if its good or bad. Today I cleaned the board more . Lots of alcohol and toothbrush on all RAMs  , on new tantalums and PMGR chip...

This portable did work some months ago. The harddrive was dead but it was working fine with the floppy drive. Recently when I tested it it was not working, Sad Mac and error code 00000014  0000CD36. Started to recap it. A lot of dirt under the capacitors. Especialy C25-C28 was very dirty...

I realize that now. Cant find any information about the chip from the label .

Thank You all for information about this complicated problem.   Before I knew how complicated this problem is, I bought two MAB8021  cheap on ebay. Unclear whats in this MASK ROM. I have not tried them. Probably this could work but looks rather complicated. The MAB 8401B could be a solution...

Ok perhaps to complicated for me. I will try to find a 28 pin MCU EEPROM thats compatible with Intel 8021H.

Perfect. That ZIP file contains two BIN files: 341-0332-a.bin  and ip8021h_2173.bin. each file is 1 kb. According to  https://github.com/MisterTea/MAMEHub/blob/master/Sources/Emulator/src/mess/machine/mackbd.c  that file is: "  Apple Macintosh original/512/Plus keyboard" I will try to burn...

Thanks Paralel for the information about the microcomputer. My programer can not program the 8021 so I will not try to read from the working 8021. Interesting if its possible to program to EPROM but I suppose thats rather complicated.  I found some information regarding this problem in...