LC III recapped. I get a chime on boot, static after

[DamienC]

I picked up an "untested" LC III that of course just needed caps. Recapped the power supply first, and the system powered up and worked fine.

Then I cleaned the logic board and recapped it. The system booted first time with a chime, so I thought all was well and forgot about it for a bit.

When I went back to the system later to reinstall an OS on it, I noticed that even though I got the startup chime, all sounds after that were just static (for lack of a better description, a "fart").

Went back and rechecked all my caps, all were in the correct orientation.

I'm going to recheck everything with a magnifying glass and probably ring out the UB10 with a schematic when I get the chance.

In the meantime, is there anything obvious I could check? I did have an LC PDS ethernet card installed and read that they could cause problems, but the issue persists whether the card is installed or not.

I'll post some pics of the board as soon as I can get my kids to leave me alone. So maybe never lol.

 

[_nec6678]

My LC II makes a startup chime, followed by a loud feedback sound. I noticed that I can adjust the pitch by wiggling a chip that is in the path of some corrosion. Since you cleaned your motherboard (and the LC III is pretty different from the LC II), our problems are probably unrelated, but I just wanted to share. My LC II doesn't have a hard drive, and I haven't properly booted off a floppy since the video output doesn't seem to work, and I can't see anything. (I converted the DB-15 output to 15-pin D-sub for a VGA monitor, which says something like "the signal is out of the frequency range". I blame it on the LC II, since I use the same setup for my IIx, and it works just fine.) So, I think I have bigger problems with my LC II, and I am not in any hurry to fully restore it.

 

[vtgearhead]

Heh. My LC II did the same thing - wild squealing that changed with pressure in the left rear of the board. A recap later all was good. I think I lucked out and caught it before too much damage had been done.