Aion Nimbus Overdrive - Low output on charge pump

[chromesphere]

Hey guys,
i dont usually do repairs for other people (effects that didnt work after building) but this guys been helping me alot lately so wanted to go the extra step.

Build doc and schematic

There were multiple problems with his build but i think i have fixed them all bar this last one.  For some reason the charge pump is only output -0.3 volts.  There is ~8.2v on pin 1 and 8 of the charge pump.  Positive side of c15 is getting ~8.2v as well.

Everything after the charge pump is very low.  Also the charge pump is slowly heating up.  I've checked for solder bridges around the charge pump but there are none. 

Any ideas where to look?
Thanks in advance!
Paul

[micromegas]

This might sound silly, but have you checked there isn't a reversed diode? It has happened to me before...   

[chromesphere]

Hey Al, thanks for the reply!  Yeah thats the first thing i thought (0.3v could be a diode) but alas, no...

[mgwhit]

Reversed or damaged cap on C16 or C17?  Have you swapped the charge pump yet?

[RobA]

Which charge pump does it have in it?

[chromesphere]

TC1044scpa.  Surely it can handle the current draw?

Voltage on the caps looks right...

This ones got me stuffed...

[TGP39]

I would definitely try switching out the charge pump. Who knows what it's been through before it got into your hands.

Steve.

[chromesphere]

Sorry forgot to mention i tried that, same outcome! (was one of the first things i did).

[TGP39]

Paul. Are you getting the same voltage reading on pin 1 and 8?
If you can, give us the voltages on the charge pump pinout.

Steve.

[chromesphere]

Good idea!  Here we go:

1 ) 8.25
2 ) 4.06
3 ) 0.01
4 ) -.242
5 ) -.06
6 ) 3.6
7 ) 5
8 ) 8.26

D5:
Negative: same as pin5
positive: 0.73

Output voltage of the charge pump slowly drops and it gets hotter, took me a while to measure it this time so its really low...

There's a connection error somewhere.  Ill look AGAIN for solder bridges..

[TGP39]

Do you think re flowing to socket would help? The charge pump socket.
Steve.

[chromesphere]

Would you believe ive done that too lol its one of those builds...I think im going to have to bin it...fustrating because atleast i feel like im getting close fixing it

[mgwhit]

I'd swap the electrolytics before I binned it.

[chromesphere]

Thanks Matt, ill try reflowing them first then swapping them!

[TGP39]

Keep us posted Paul. Let's get this thing working.

Steve.