Hello all
I am trying to re-align my TR7. So far I have followed the Service Manual
and am now trying to align the 8.05MHz Oscillator. (Section 3-5 in the
Service Manual).
I can't seem to measure a stable output on pin 40. It seems to be wandering
around between 2 and 7 MHz. Additionaly on the
Adrian -
Just a guess, but is your counter sensitive enough to measure the 8.05
MHz signal, it's only about 0.1V p-p. It's unlikely that the oscillator
is wandering that much if it's running at all. Are you sure you're not
in AM mode? The BFO has to be ON. It's also possible that your
Has anyone got a decent copy of the circuit diagram of the PBT/Reference
Board for a Drake TR 7 ?
In particular I could do with figuring out what contacts / edge connectors
relate to. At the moment I am trying to isolate a rather tricky fault.
The symptoms are that the PBT (when selected) has
Hi Folks,
I have 2 spare 400V 22microF and 2 spare 200V 22microF. The former are
quite bigger than the latter ones but both types could be soldered
underneath the old big can as there is enough space. I would like to
make things as simple as possible and mechanically durable. How would
you
Frank -
The 200V caps would be ok. Later versions of the AC-4 used 40 uF
capacitors for C5, so if you can find bigger ones it would be better.
You must disconnect ALL wiring from the old can type capacitor. Best is
to mount an insulated terminal (tag) strip near the can, soldered to the
Be sure to discharge the old capacitors before working on the power
supply. Here is a link to some good information on the AC-3 and AC-4
power supplies.
http://www.wb4hfn.com/DRAKE/DrakeArticles/TechTips/
PowerSupplyTroubleshooting.htm
Al, n7ioh
On Jan 27, 2010, at 9:18 PM, Garey Barrell
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