[time-nuts] Rpair of an 8662 HP Generator

[John Miles]

> My  signal generator has a poor, intermittent power  supply.  The RF
> section is ok. Who can please tell me which company can and  will fix these
> older
> but excellent  generators?
> 
> Thanks, Ulrich

Have a look at the capacitors in the voltage divider that drives the bases of the switching transistors.  There's a good chance that's your problem, and they probably need to be replaced even if not.  75-TVA1607 (Mouser p/n for Sprague TVA1607) works well.  

It would be nice to use 105C parts if you can find some, but the 85C TVA1607s have worked well for me in multiple 8662As over several years. 

The other likely suspect is one of the large screw-terminal electrolytics on the motherboard.  The power supply can almost-but-not-quite start up when one of those is completely open.  High ESR is very likely to cause intermittent operation. 

-- john, KE5FX
Miles Design LLC