Do I have a bad charge pump (7660s)?

[nate433]

I built the Reccurring Nightmare (Echo Dream) from FuzzDog. The modulation isn't working. I read that the 2206CP needs something like 12V to work. So I measured the charge volt pins

Pin 1: 9.8v
Pin 2: 5v
Pin 3: 0v
Pin 4: 133.6 mv
Pin 5: 344.8 mv
Pin 6: 5v
Pin 7: 6.5v
Pin 8: 9.8v

I may be totally misunderstanding how charge pumps work but shouldn't pin 5 be double VCC?

Thanks!

 

[spi]

No, you should check if you're getting 18V at the cathode of D3.

A charge pump works by charging up C12, which combined with +9V at D2 will increase voltage at D3.