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#1 2015-12-06 19:42:11

Elfen
Member
From: NYC, NY
Registered: 2015-07-07
Posts: 20

Another Squealing LC?

Perhaps I can get help here. I got no response from the other forum...

History:
I bought this LC as part of a set of 4 for cheap, knowing that is was dead. It like the others, were recapped, and from the looks of it, the previous owner did do a great job in the recap. But he killed it by inserting one of the ROMs backwards and fried the ROM.

So I managed to recently get a new (used) set of LC ROMs from ebay and put in the dead ROM's replacement. Turned it on and "BONG!"

It works!

But I took out the LC's PSU to recap later and am using a non-recapped LC III PSU which I know works.

After a minute of "warming up," the LC begins to squeal, howl, fart, and make other noises. Noises that usually means that it needs a recap. But this board was recapped. So what could be wrong?

I'm suspecting the un-recapped LC III PSU.

What you guys think?

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#2 2015-12-06 21:39:38

ClassicHasClass
Member
From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: Another Squealing LC?

Nothing worse than a farting LC.

Not sure that's the actual problem, but recapping the PSU wouldn't be a bad thing.

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#3 2015-12-07 02:00:28

Elfen
Member
From: NYC, NY
Registered: 2015-07-07
Posts: 20

Re: Another Squealing LC?

The only the things I could figure is that in putting the ROM Backwards may have damaged a brand new cap or two but which? And there is still some Cap Go Residue that needs to be cleaned up. And off course, I'm suspecting the PSU needs to be recapped.

Lets see what Techknight, Uniserver and the other experts have to say...

Last edited by Elfen (2015-12-07 02:01:28)

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#4 2015-12-07 07:27:09

ClassicHasClass
Member
From: Electron Alley
Registered: 2014-05-26
Posts: 1,081
Website

Re: Another Squealing LC?

I wouldn't think inserting the ROM SIMM wrong would blow caps. Anything's possible, but it seems more likely that the computer just wouldn't work until you reseated it correctly. Cap residue does sound more probable.

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#5 2015-12-11 23:55:51

Elfen
Member
From: NYC, NY
Registered: 2015-07-07
Posts: 20

Re: Another Squealing LC?

I cleaned up the board some more though I could have used better chemicals to clean it with. So, I'm suspecting it's the PSU at this point. But I got interesting results.

Squealing is still there but softer in volume. But that depends on how much RAM I put into the LC. And which type I put in (8 chip SIMMs vs. 2 chip SIMMs - both 1MB SIMMs).

With no RAM, the Squealing eventually goes away.

With 8 chip (1MB) SIMMs, the squealing is there but low in volume.

With 2 chip (1MB) SIMMs, the squealing is louder.

I need to take apart my IIci (Don't want too!) to take out and test the 4MB SIMMs in the LC and see what is the state of the squealing.

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#6 2016-10-16 08:41:57

Schmoburger
Member
From: Australia
Registered: 2015-04-21
Posts: 281
Website

Re: Another Squealing LC?

I'm keen to find a resolution to this, as my LC is awful for it... has been noisy the entire 15 years I have had it. As it stands, I came to find myself replacing the PSU in it this year when I draggeed it out from the depths. I used a known working unit from another machine to test but nonetheless it still squeeled horribly as you describe... Interestingly though, it does not do this in the Performa 400 (LCII) from which the test PSU was sourced.


Stay hungry... Stay foolish.
G5 2.0DC, Yikes G4/500 Sonnet-Enhanced, B+W G3/450, 9600/200MP, 7600/200, iMacs DVSE Graphite and 600 Snow, 7220/200, WGS 7350/180, 6360/160, 5500/250 DE, Pismo, 2x Lombards, 6100/66DOS, 2x CC's, 3x Pluses, 512K, SE/30, SE Superdrive, 2x Classics, IIvx, IIci, IIsi, 3x LC520, 4x LC575, 5x P580, LC, LCIII, //gs LE, 2x ROM 02 //gs', IIe... and I'm outta characters!

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#7 2016-11-20 11:05:29

AlpineRaven
Member
Registered: 2016-10-08
Posts: 4

Re: Another Squealing LC?

One of my LC is doing that as well - suspect its the caps as well - it hasnt been done yet - has a high pitch squeal, and crackle etc
Cheers
AP

Last edited by AlpineRaven (2016-11-20 11:05:54)

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