E III board has burnt thingy - possible other problems - needs surgery!

[artbylaw]

I got this from the orginal owner and he said he tried sending it a couple of times to e-mu and they could fix it - told him his hard drive was "fried." Well, when I went to flip the switch, I got black smoke coming out of the back fan. I opened it up today and found this board (third one from top) with a burnt "thingy" on it. The nieghboring prom has a blackened area next to it and the yellow topped thing has some effect from it as well. Also, when I opened it, I believe maybe this and the two cards below were not completely "seated" in their sockets. The plastic post that holds them in was not seated on the bottom and I "believe" they were all sticking out a little. Not positive, but it seemed that way when I was taking them out of the unit itself.
Everything thing else "looks" very good - lcd did not show any characters before I turned it back off when I saw the source of the smoke. Any help direction would be greatly appreciated. I have a friend that can help with getting what I would need and the soldering. I have an E64 sampler also and would love to get this baby working as well.  Thanks!

[artbylaw]

OK, it looks like I'm needing to replace the capacitor for C-49 and C-54.
Any help as to what kind of replacement to get...or where?
Thanks in advance. I promise to document to whole process of repair and post for future reference.
Larry

...c'mon, we're supposed to help each other out right? 

[mg73]

Is it the ADC board you mean?
If
C49 is 10uf 16v tantalum
C54 is 0.1uf ceramic 50v

Tants are notorious for short circuiting,
with flames and smoke.
Hopefully it didn´t take anything else with it.

Start by replacing C49

[artbylaw]

Thanks so much for the reply, mg.
Here's the board info to make sure we're talking about the same one - if you could please confirm.
Sounds like we are and I've definitely seen smoke. Everything else "looked" pretty good tho, so I'm hoping for the best there.
I even ordered another hard drive - same make and model - Quantum Maverick to try as a replacement if it gets to that.
I'll keep everyone posted for results.....Larry

[mg73]

yes right.

Start with C49 ad see if it works.
Also if possible try to get a CF card HD instead.

[mg73]

forgot,
pm me if you want the service manual
could be handy.

[artbylaw]

Update 4-26-12
Changed out capacitor C-49 and it lit up again when turned on.
It looks like the back of this board might be "missing" a connector or two judging by the looks of the remains.
I will take some pics and give a link to photobucket to see if someone can help.
If someone can forward me a schematic of this board ( I have the service manual - thanks mg73! ) - or can take a pic of their "working" board" - I'd be forever grateful and can continue the quest!

[artbylaw]

OK - I've created a photobucket album with large pics - http://s917.photobucket.com/albums/ad13/artbylaw_photos/EMU%20EIII%20ADC%20PCD%20BOARD%20PC%20335/
I show the full board with highlights/#'s when looking at the close up possible problem areas.
If anyone sees something missing or not right, can you please let me know what the problem is.
Thanks a million 

[artbylaw]

Anybody??  Anything??
No one has a pic of the back of this board or can take a quick look at mine to see what might be the problem?
There's way too much knowledge here...I know someone will come through - so thanks in advance 

[Alan EIII]

Pictures of mine:

dirty but ok : No compoments on most burned places showed on your picture.
The revision is the same.



To fix our issue I think we should start from the PSU.
There is a wrong voltage applied to the board
Check the voltage / recap it.

then we'll have to look for damaged chips like the one on my cpu board...

The board order is:

 1 microcontroler board (the one with the 4mb / 8mb memory modules)
 2 Cpu Board
 3 The A335 ADC
 4/5 the output Boards 1/2

[artbylaw]

Thanks Alan, it least that's a couple things that look ok.
The boards were in the correct order also.
I'll have my friend look at the psu.
I only have a reference manual. What should the voltage be?

[Alan EIII]

I'm going to send you the service manual.
I remember seeing a post about how to calibrate the PSU

Also there could be a short somewhere on one of the board.
look for bended compoments on the boards.

Also if they reported the HD has "fried" I suggest to go "light" on your next retry (I mean disconnect the HD and the Floppy)

Pm me your mail adress.

Your EIII may have been in several repair shops;
What did the seller told you about the fixes done before?

[Alan EIII]

To test the psu voltage:

(From service manual)

Green is ground

Verify +12v on orange wire
Verify +5v on yellow wire
Verify +14.25v to -15.75v on black wire
Verify +14.25v to 15.75v on red wire

[artbylaw]

This will probably sound dumb, but should he "re-cap" the burnt capacitor again "before" he tests the voltages?
(I have 23 of them to fire off    )
I will make sure to disconnect the hard and floppy drives too.

[Alan EIII]

I would do the test with the connector unpluged.
there wont be any current applied to the cards.

So you dont need to change the cap (you'll do it after)