[Drake] TR-7 problems

[Garey Barrell]

Ken -

Check the 10R and 10T busses.  Marked on the bottom of the "parent board".

10R should be very near +10V in Receive and 0 in Transmit.

10T should be very near +10V in Transmit and 0 in Receive.

I suspect you might find that 10R is +10 in both!  If this is the 
problem, check the 10R and 10T "fuses" (cleverly disguised as 
transistors) at Q306 and Q307 and located on the Transmit Exciter 
board.  (Where else?!?)

73, Garey - K4OAH
Atlanta

Drake 2-B, 4-B & C-Line Service Supplement CDs
<www.k4oah.com>



Transmaster wrote:
> Well I finally got the TR-7 fired up and it has a serious problem in
> the transmitter.
> When I key i t it sounds like it is in some demonic digital mode. It
> is a staccato high pitched tone "dee-dee-dee" you can hear my voice in
> the background but it is totally unintelligible. If this was a vacuum
> tube transmitter I would say there is RF getting into something but
> being solid state I don't really know.  I am not set up for DX'ing
> solid state gear.  What kind of test equipment do I need to add to my
> collection to work on this rig?  I have the usual VTVM's, digital
> multi-meters, O scopes, tube testers, RF/audio signal generators, etc
>
> Ken de W7ITC