Amiga 2500 Mouse PotY, PotX problem

[save2600]

@ JimS:

ROTFLMAO! Maybe you had an Amiga 2000 'especial' where someone from South America douched down the mobo with WD-40   ;-)    LOL!

[rkauer]

 Not me! I never used WD40 or a-likes near an Amiga! Can you name the stoopid? :inquisitive:

 Here I have a totally destroyed A4000 (not by me!) were the guy had a battery leakage and he try "fix" it with iron wool  !!!!!!!!!! :whack: :furious:

 Now the board is on my hands, but not much to do with the "corpse". :headwall:  

[save2600]

Steel wool?!?  Okay... but traces can be repaired. I've soldered wire the thickness of hair back in place. That's what needs to happen in your case. If your board is so shot to where you can't see where traces are supposed to go, get a close up pic of the board and go from there! Nothing to lose since the board is already toast. Still... can't imagine *that* much leakage ruining an entire block of traces you can't "trace"... unless the guy was very liberal in his application of the steel wool!   LOL!

[rkauer]

 He was...

 The leakage covered all the SIMM sockets, RTC, mouse and game ports.

 I don't know what else he did, but simply there are no traces any more.

 OK, I'll stop thread hijacking. ;-)

[amigaksi]

>The leakage covered all the SIMM sockets, RTC, mouse and game ports.

>I don't know what else he did, but simply there are no traces any more.

Perhaps, it's possible to minimize the repair work with an add-in board or CPU card.  Use Mouse from some serial board, memory from some CPU card or memory board and forget about the RTC.  

[amigaksi]

>by JimS on 2009/2/8 21:43:10

>>save2600 wrote:
And a blown trace could have happened because of battery acid leakage you're thinking JimS? Or sloppy techs dropping their screwdrivers on the mobo too I guess. lol

>Possible... but I was thinking more like the trace acted as a fuse and vaporized. I've seen it happen on some machines that came in for repair. That's why they added the fuse, both to the joystick ports and the external video port as well.

I think I vaporized something on my A500 long time ago by pluggin in a Mimetics genlock into the computer while Amiga was on.  The genlock died instantly but Amiga 500 still works great but it no longer works with A520.  The monochrome video out still works.  Any picture of where that fuse is on video port on A500?

[JimS]

amigaksi wrote:
I think I vaporized something on my A500 long time ago by pluggin in a Mimetics genlock into the computer while Amiga was on.  The genlock died instantly but Amiga 500 still works great but it no longer works with A520.  The monochrome video out still works.  Any picture of where that fuse is on video port on A500?

I don't see any fuses on the 500 schematics. But it does sound like you've fried a trace. Check pins 21 (-12v), 22 (12v), and 23 (5v). If you can't see the open trace, you can use 30ga wire to tap the proper voltage from somewhere else on the board. I'd consider soldering in one of those fuses just in case.

[JimS]

save2600 wrote:
ROTFLMAO! Maybe you had an Amiga 2000 'especial' where someone from South America douched down the mobo with WD-40   ;-)    LOL!

Well... I don't know about that... at least it wasn't duct tape. ;-)
But I have seen a few strange failures. Like a bad CIA missing one bit to the printer port. So every time a character with that bit on printed, it came out wrong... but other characters printed fine. Or my own 1000 that had a stuck RTC in it's CIA chip. The system time would run for about 10 seconds then jump back groundhog day style and restart. Kinda useful for hack lite that was seeded off the RTC. There were only a few starting positions, and once you memorized them.... ;-)
I once had a similar problem on the mainframe I used to repair. It's backup RTC counter was broken and was basically running at about 4 times real time. We had to switch to the backup for other problems and nobody noticed the glitch until the system's clock thought it was the next day. They decided to stop all work until the world caught up with the computer. ;-)

[Prime]

Well this thread kind of went a weird direction, but a perfect segway for a couple of questions:

I have an A3000 I just got, the mobo is in pristine condition and the battery was just starting to leak. I removed the battery and directly under the negative side there is a small place where the green solder mask chipped away to reveal copper. (A very tiny bit.) Should I drop some RTV on there, tin it or leave it alone?
And what is the "preferred" method of making sure any acid crystals get off the mobo? I have been spraying the area with flux cleaner.

Thanks,

[taunusand]

It should be fine if you tin it.