Possible dead ROM chip?

[CompuNurd]

I was working on an LC II board I was selling, and fired it up one more time before putting it in a box. Nothing, just a blank screen, not even the chime, it must have spontaneously died overnight. I got this board with a ROM installed backwards, which I discovered from the smell of burning dust rising from the machine. I swapped the ROMs with those of an LC, since the LC had problems of its own, and it worked. I am wondering if for some reason, the ROMs from the LC transplanted into the LC II, caused some sort of problem, possibly due to incompatibility?

If you are looking at ROMs from LC to LC, is it fine to swap ROMs, even if the new ones aren't the same brand/type?

 

[uniserver]

LC-II roms work in the LC-I

but LC-I rom's don't really work in the LC-II...

I maybe got a LC-II once to boot with LC-I roms, but it was screwy… most of the time it will bong and then sad bong a few seconds later.

and get use to it…   crap always decides to die the last time you test it,  always after its sold… and just before it goes into the box… murphys law...

its important as hell to wash those LC Mobos…  wash them great with soap scrubber and super hot water. after you remove the caps… and always blast off with compressor really well. if you do not… you run the risk of thinking it works… and all is well… but some of that conductive liquid GOO is sitting under an I/C is cooking, and waiting to pop a trace or VIA.

 

[CompuNurd]

I don't think washing is the issue, I soak all the boards in ammonia, acetone, and water in a pan for 5 minutes before scrubbing with a toothbrush, then repeating 1-2 times before rinsing with the sprayer in the sink. I shoot it with a compressor until there is no water, and I try to shoot under ICs as well.

I have a Performa 400, which is really just a re-marked LC II motherboard. I could probably swap the ROMs and see what happens. The person I am trading with has a dead LC II motherboard, so if the swapping ROMs thing works, I could probably just send him a ROM-less board and he could do the swap with his board.

If not, I guess I will wash it again.

 

[uniserver]

i personally wouldn't do all that .

i would just de-cap and wash as i said with soap and and water, scrub.

no immersion…  espically no immersion, in fancy chemicals.  especially in acetone … as to whoever told you to do that beats me.

then compressor dry.

I only suggest acetone in a little bottle with a stainless applicator, just use a little squirt of that with q-tips to clean the pads up like new, after you flux and wick them. there are many things on the pcb you do not want acetone on or in.

and I'm not for any immersions ever.

i'd, make sure to slap some other rom's in it, to make sure it works before you sent it out.

sending him a dead board, would not turn out so nice.

 

[CompuNurd]

i would just de-cap and wash as i said with soap and and water, scrub.

no immersion…  espically no immersion, in fancy chemicals.  especially in acetone … as to whoever told you to do that beats me.

https://68kmla.org/forums/index.php?/topic/23962-cleaning-cap-goop-from-logic-boards/?hl=cap+goo

"you can do this in a bucket with a tooth brush"

I assumed he meant to put the actual board in a bucket.

Around 3:30 he talks about ammonia and a degreaser, with some water in a tub to submerge the board in.

 

[uniserver]

Ah ha.

 

[uniserver]

he should be careful with all those chemicals…. Ammonia + Chlorine = well…. 

http://chemistry.about.com/od/toxicchemicals/a/Mixing-Bleach-And-Ammonia.htm

 

[techknight]

The first thing that pops up is jolly roger.... AWESOME

 

[CompuNurd]

I cleaned a few bad looking chips with acetone and a Q-tip, then I freshened up some solder joints and I now have a good board again!

 

[Elfen]

Congrats! It's a boy!