Notices by trebroNdotnet (trebrondotnet@mastodon.social)

@codewiz I had the same problem. There is no direct mechanical necessaty for longer/shorter screws for the terminals. So I made my on decision.

@codewiz I simulated the part of the schematics with falstad.com:
https://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWEAOM0CcAmSAWMA2SAdn3xLCQUhEuoQFMBaMMAKABMQBmL-cLEHj5gBmcADk8OZB269+Ynn0w5qYsJLDTWAJznDMyfQqiCikXcZXUlIQ0eo5zrAG7HeR211ynHN6HzUQdAIrADu7j629lCsAOZ2qtzIOImOXGJBrABKggQmQuCGvoJ0JTChubZgxbb4qUGlReUhrNjo4IR2CMJdXAhiDbDwuEQ0sAhcNciYXETmkPhgYzBwEDAQbADGdirdynv9g+BMYwgTU4az83BLK8Pr4Z1qPbupmK8WEQQ2A2-cfy+aWS70OgKemD2Hz40SSQK8+CM1hBsT0LDE0PANQBmXAIye6P2zyJQMJR2J5IsQA

If you remove D191, you rob U190 the voltage while the A3000 ist powered on.

What is D190 for? I have no idea...

If you want to disable the charging, I would suggest to just replace R192 with a blocking diode.

#amiga #electronics #a3000 #battery #charging

@codewiz ...measuring pin 3 on U112. Looks like the same. I doubt, that reset is your problem as the amiga basically runs...

What happens if your amiga is running and you "bend" the board slightly?

We can do a videocall if you wish. But that would be a lot of camera handling involved:-)

@codewiz Unfortunately not. It only helps to proceed systematically: Are the voltages from the power supply stable? Does the error pattern change when you put pressure on Paula, Denise and Agnus (PDA). PDA - does heat or cold cause changes? I have learned a lot from the repair section on a1k.org. Register there, write 5 posts and a world of repairwizardry opens up... I only stand on the shoulders of giants :-)

@codewiz Sometimes it helps if you reseat the socketed ICs. The PLCC ones are hard to take out. The plastic of the PLCC sockets becomes soft or brittle. Apply pressure on the sides? Anything changes?

@codewiz So far, so happy - AmigaTestKit and DiagROM showed no errors. Amber is working, clock recalibrated. Had some issues to get the SuperKickstart Disks working - as I had no experiences with the kickstart 1.4. Further tests necessary, but its promissing so far.

Spare parts delivered and soldered back to the board.

Cleaned and reseated the socketed ICs...

...and slowly turned the power switch 😉

"We have picture!" (tm, Sorin Electronics)

#amiga
#a3000
#vintagecomputing
#retrocomputing
#batterydamage
#restauration
#electronics

@codewiz I had problems in these places. Even further away, where you wouldn't have expected it.

Every dark pattern is a suspect. And it hides well under the components.

If I get a battery damage to my desk - usually I do not even bother to power it on. But good to see your amiga half to life in this state allready!

...and if you invest in lab equipment: A microscope has changed a lot for me 😉

@codewiz There are A3000 with early Kickstarts softloading the Kickstartfile to FastMEM. All other A3000 should work with just ChipMEM.

This is the current state of my repair attempt. And now I have to wait for the ordered parts...

#amiga
#a3000
#vintagecomputing
#retrocomputing
#batterydamage
#restauration
#electronics

@codewiz ...as long as we plant a new chip meadow everything will be fine 😃

@codewiz Desoldering: add fresh solder, snip the sockets to smaller peaces, "lots" of heat. Desoldering gun did nothing here... Main goal is to keep the pcb alive!

PCB-orientation: https://retrobox.it/files/pcb/Amiga_3000.html

Schematics: http://amiga.serveftp.net/Schematics/A3000_schematics/A3000_R9_schematic.pdf

Gerber: http://www.reamiga.info/webfiles/R3000/A3000Rev94.zip

...after cleaning and careful drying we can begin to remove all affected parts from the board.

#amiga
#a3000
#vintagecomputing
#retrocomputing
#batterydamage
#restauration
#electronics

I will update my restauration as I go... @codewiz is also restoring an A3000. Worth watching as well:

https://mstdn.io/@codewiz/113561527808236797