Early rev of the protoboard charge pump heat

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geargasstore

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Has anyone had any issues with their protoboard frying charge pumps?
I feel like there is something wrong where the 9v plane is bridged somehow, not sure though. Its one of the earliest protoboards (its black in color).

I can still get by with no chip, just won't have -9 and 18v.....

Thanks
Ernie
 
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Nothing on the 9V line would damage the charge pump (unless of course it greater than 9V)

Is this happening with nothing plugged into the power supply pinheaders?
 
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geargasstore said:
Has anyone had any issues with their protoboard frying charge pumps?
I feel like there is something wrong where the 9v plane is bridged somehow, not sure though. Its one of the earliest protoboards (its black in color).

I can still get by with no chip, just won't have -9 and 18v.....

Thanks
Ernie
Click to expand...
Is it oriented correctly? A backward charge pump can get really hot to the touch and even spark.. Ask me how I know. :(
 
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Robert said:
Nothing on the 9V line would damage the charge pump (unless of course it greater than 9V)

Is this happening with nothing plugged into the power supply pinheaders?
Click to expand...
Yeah, if nothing is plugged into the headers. I went to check the 3.3, 5, 9, -9 18v just to double check and I was getting low readings. Then I put my usual finger on the top of the charge pump and it was scalding hot (I blew through a few, tried 1044, lt1054....)

The only other time this has ever happened is when I had a stray lead get caught underneath the socket where it bridged a few pins :)

Its ok, I can live with it for now, but I'll keep testing the board.

Thanks
Ernie
 
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It could be a short or a bad diode in the charge pump circuit.

What sort of resistance do you measure from the power supply pin headers to ground?
 
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Robert said:
It could be a short or a bad diode in the charge pump circuit.

What sort of resistance do you measure from the power supply pin headers to ground?
Click to expand...
The resistances are:

ref: ~10k
3.3v: 620ohms
5v: 940ohm
9v: 940ohm
-9v: 300k steadily slowly increasing.....
18v: 300k steadily moderate increasing.....
(its a fluke autorange so for the increasing values, it just keeps going up in increments)

Thanks
Ernie
 
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