[sdiy] May Be Somewhat OT: Repairing a DOD 1222 XL Mixer

[Scott Gravenhorst]

Hello all, 

I'm not sure how off topic this is, it has to do with the mixer I use when recording with my synthesizers...

Anyway, one of the 4 power supply filter electrolytic caps is obviously blown, so I've ordered them and they should arrive in a few days, I will replace all 4.  

Does anyone have one of these mixers?  

On the rear next to the rectangular hole where the power connector for the wall wart is, there is a round hole - what is supposed to be there?  

Also inside on the "power board" (which is a combination of power supply with two 3-term regulators and also has all of the 1/4 inch output jacks), there is something that looks like it was unsoldered and removed - but I didn't do that, it's labeled H4, has 3 holes for soldered connectors two if which are shorted together and the third is by itself (so it really has only two connections).  The wallwart socket connects directly to these pins, one side to the shorted pins, the other to the alone pin - as if 
there's an indicator light, but the transformer is AC, so I'm assuming it's not an LED.  The wallwart is 10VAC, 1.8A - so it can't be a neon bulb.  At first I thought it was a power switch, but that can't be because if it were, it would short the wallwart when closed.  

It's been broken for over a year now, and I've got a bad habit of leaving things like this turned on - I can't remember if it ever had a power switch.  It has a power LED indicator on the front panel, but I cannot find a power switch (other than the phantom power switch for the microphone connectors).  

It was not very expensive when I purchased it and I've googled until I'm blue in the face for schematic for it.  It's old enough that all parts are through hole.

Can anyone help - either with a quick look on the back (don't need to open it up) or perhaps someone has a schematic?

Thanks in advance for any info.

-- ScottG
________________________________________________________________________
-- Scott Gravenhorst
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