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JD-800 - Main Board vs Coca-Cola

JD-800 - Main Board vs Coca-Cola

2013-02-27 by 65 Lotus

Been trying to ressurect a JD-800 main board that got spashed with Coke probably 25 years ago and then sat. Nothings really corroded; I've removed chips from the worst areas. Everything works ok except for the sound lines.
I traced it back to the (8) digital lines coming out of the CPU. Using a 10x and looking at the CPU pins, sure enough, a big blob of brown goop is residing right under the digital pins. I've found saliva to be the best remover of old Coke, but, uh, yeah. Not here please.
What's the best way to clean old Coke out from under a surface mount microprocessor? I do have access to lots of deionized water if that helps.
Help!
Scott in Ohio

Re: JD-800 - Main Board vs Coca-Cola

2013-02-27 by The Wizard

I'd take the board out of there and flush it with lots of warm water, and then blow dry with a compressor, or hairdryer (on a low setting).
Another option is this:
http://www.youtube.com/watch?v=DwRlZyIG6rg
---Kevin (not Lightner)


--- In vintagesynthrepair@yahoogroups.com, "65 Lotus" <Lotus@...> wrote:
Show quoted textHide quoted text
>
> Been trying to ressurect a JD-800 main board that got spashed with Coke probably 25 years ago and then sat. Nothings really corroded; I've removed chips from the worst areas. Everything works ok except for the sound lines.
> 
> I traced it back to the (8) digital lines coming out of the CPU. Using a 10x and looking at the CPU pins, sure enough, a big blob of brown goop is residing right under the digital pins. I've found saliva to be the best remover of old Coke, but, uh, yeah. Not here please.
> 
> What's the best way to clean old Coke out from under a surface mount microprocessor? I do have access to lots of deionized water if that helps.
> 
> Help!
> 
> Scott in Ohio
>

Re: [vintagesynthrepair] JD-800 - Main Board vs Coca-Cola

2013-02-27 by Daniel Forró

JD800 was manufactured since 1991 :-)

Anyway it's very nice synth which deserves to be repaired. I have no  
advice concerning your problem but wish you success!

Daniel Forro
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On 27 Feb, 2013, at 10:20 AM, 65 Lotus wrote:

>
>
> Been trying to ressurect a JD-800 main board that got spashed with  
> Coke probably 25 years ago and then sat.

Re: [vintagesynthrepair] JD-800 - Main Board vs Coca-Cola

2013-02-27 by jammie

send it off to get washed in a sonic bath
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----- Original Message -----
From: 65 Lotus
Sent: Wednesday, February 27, 2013 1:20 AM
Subject: [vintagesynthrepair] JD-800 - Main Board vs Coca-Cola

Been trying to ressurect a JD-800 main board that got spashed with Coke probably 25 years ago and then sat. Nothings really corroded; I've removed chips from the worst areas. Everything works ok except for the sound lines.
I traced it back to the (8) digital lines coming out of the CPU. Using a 10x and looking at the CPU pins, sure enough, a big blob of brown goop is residing right under the digital pins. I've found saliva to be the best remover of old Coke, but, uh, yeah. Not here please.
What's the best way to clean old Coke out from under a surface mount microprocessor? I do have access to lots of deionized water if that helps.
Help!
Scott in Ohio

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Re: [vintagesynthrepair] JD-800 - Main Board vs Coca-Cola

2013-02-27 by PeWe


Then it was a Coca Cola lite ... :-))


Am 27.02.2013 02:50, schrieb Daniel Forr\ufffd:
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\ufffd
JD800 was manufactured since 1991 :-)


Daniel Forro


On 27 Feb, 2013, at 10:20 AM, 65 Lotus wrote:



Been trying to ressurect a JD-800 main board that got spashed with Coke probably 25 years ago and then sat.\ufffd


Re: JD-800 - Main Board vs Coca-Cola

2013-02-27 by scott frye

warm water may work or dunk the whole board in bath of 91% alcohol and let it soak over night then flush
a large zip lock works

--
Scott Frye

Audio-fixation.net

Vermont

JD-800 - Main Board vs Coca-Cola - [Solved]

2013-03-02 by Scott

Symptoms: Synth would boot up fine and operate ok via the display but no sound, only a nasty snapping and crackling in the outputs. Passed all ROM and other tests. Jack Board verified ok in a working JD800. Main board in question was an obvious victim of a Coke spill.

Removed, cleaned, and replaced the main program ROM, CN10 and a few of the square black filters around CN10. CN10 is the connector carrying serial, timing, MUX, and clock data to the Jack Board for D>A conversion to sound.

After solder ops above, let the board sit in a warm water and Dawn mixture for about an hour, worked it in and around with a soft chip brush occasionally. Rinsed in deionized water and sprayed with canned air. Heated kitchen oven to 170 °F and turned off. Inserted the mostly-dried board into oven and left overnight.

Reinstalled in synth and no longer crackling. Only total, dead, complete, utter silence. DAMMIT!

Checked CN10 pins with a scope. MUX muxing. Serial serialing. Timers timing. Clock signal going into FL7 inductive t-type filter but not coming out. HA! 

The raw, unfiltered signal looked good enough to drive a chip, so I removed the Panasonic filter and simply jumpered where FL7 used to be. Has been working fine now for several hours.

Working to source a replacement filter for long-term stability, but you gotta love it when a plan comes together.

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