Vintage Synth Repair

Typically the feedback cap drys out.  It is typically 22uf or 47uf in this circuit.  Other caps may also be going south.  This is also a good time to improve the filtering by bumping up the values of the filter caps a bit too!  





>________________________________
> From: "narfman96@..." <narfman96@...>
>To: vintagesynthrepair@yahoogroups.com 
>Sent: Sunday, September 29, 2013 6:00 AM
>Subject: [vintagesynthrepair] RE: Dead PS board in DX7
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>The mk1 power supply gets quite warm. This also can lead to bad solder connections. 
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>---In vintagesynthrepair@yahoogroups.com, <kloopy@...> wrote:
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>I had an issue with power supply on my DX7 MK1 and it was dry joints on low power output. Hope that may help someone.
>K 
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>---In vintagesynthrepair@yahoogroups.com, <oldcrow@...> wrote:
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>That is glue.  Tall parts were generally glued down so their high 
>center of gravity wouldn't end up cracking the board or otherwise weaken 
>their connection to the traces/pads.
>
>Crow
>/**/
>
>synapticdistortion wrote:
>
>>
>>>>
>>>> One thing that I've noticed is that there is a hard, tan-colored
>>>> substance at the bottom of several of the caps.  I can't tell if it's
>>>> leakage, or some sort of thermal material that was placed there during
>>>> manufacturing.  The caps in question otherwise look fine (no bulges or
>>>> splitting).
>>>>
>>>>
>>>> 
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