E-mu Emulator Sampler User Forum for the EIII EII EI and EIII XP

General Category => EIII Technical Issues / Tips => Topic started by: artbylaw on April 14, 2012, 05:45:00 PM



Title: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on April 14, 2012, 05:45:00 PM
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!


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on April 17, 2012, 08:12:26 PM
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?  :D


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: mg73 on April 18, 2012, 03:32:12 AM
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 didnĀ“t take anything else with it.

Start by replacing C49


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on April 18, 2012, 05:09:03 AM
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


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: mg73 on April 18, 2012, 05:48:28 AM
yes right.

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


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: mg73 on April 18, 2012, 05:49:27 AM
forgot,
pm me if you want the service manual
could be handy.


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on April 26, 2012, 07:36:14 AM
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!


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on April 28, 2012, 11:50:02 AM
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  ;D


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on May 02, 2012, 07:53:16 PM
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  ;)


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: Alan EIII on May 12, 2012, 06:56:24 AM
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




Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on May 12, 2012, 08:08:14 AM
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?


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: Alan EIII on May 12, 2012, 09:31:05 AM

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?





Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: Alan EIII on May 12, 2012, 11:16:36 AM
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


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: artbylaw on May 12, 2012, 12:37:21 PM
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   ;D )
I will make sure to disconnect the hard and floppy drives too.


Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: Alan EIII on May 12, 2012, 01:36:19 PM
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)



Title: Re: E III board has burnt thingy - possible other problems - needs surgery!
Post by: Alan EIII on May 22, 2012, 08:33:22 AM
Hi Artbylaw,

Any progress?