[time-nuts] DG535 triggering problem
kevin at rosenberg.net
Fri Dec 16 16:20:50 EST 2011
On Dec 16, 2011, at 11:25 AM, Brooke Clarke wrote:
> Just a guess. If line triggering does that there may be a problem with the power transformer.
> Use an Ohm meter to locate the transformer terminals for the AC line and then check from one of those to all the other terminals.
> I suspect there's a short in the transformer.
> Look at U502 to see of it's burned up.
Actually, I'm more confused what U502 actually is.
The revision M manual calls it both a LM2901
quad comparator (parts list and two sections)
as well as a MC12040 phase comparator.
The little PCB soldered into U502 has MC12040
silk-screened on it.
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