Brian -
The receiver is 'dead' from where? Audio output? S-Meter moving? IF
noise? Make sure ALL the front panel buttons are 'out', and the CNTR
switch on the rear panel is in the NORM position.
If the display is STEADY at 11100.0, there is a problem on the DR-7
board, or one of the pins on this board are not in the socket.
I'd start by unplugging and replugging ALL boards in the card cage. You
don't have to pull them all the way out, just enough to move them in the
sockets. You'll have to remove the DR-7 board to get to the ones under
it of course. Read the procedure in the Service manual carefully. A
digital photo before you start is a good idea, as the connectors around
the edge of the DR-7 are NOT keyed in any way. Most will fall back into
place by 'wire memory', but a photo is good insurance. Ensure that the
pins on the bottom of the DR-7 board are _straight_ , and that they
enter the appropriate sockets. It's also worthwhile to reheat all the
large pins on this board as they are prone to cracking from mechanical
stress.
There are no 'male' connectors on the small coax cables between boards.
Be sure the center conductor of the cable is straight, and enters the
female connector correctly. It's not necessary to remove these cables
to 'reseat' the cards as described above.
If you still have problems, check the DC voltages on the small Power
Supply board (the row of pots across the top) just behind the front
panel Logo. Be careful to not bump the rightmost pot in the row.
Changing this pot makes it necessary to completely realign the radio,
which you will probably want to do eventually, but no point in adding to
the current 'problems'. The "-5V" supply typically reads about -3.5V,
which is normal. The others should be very close.
If STILL problems, report back!
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs
<www.k4oah.com>
Brian Koontz wrote:
I inherited a TR-7 (serial #4388) from my father (SK). Fortunately,
I was also able to locate the service manual and extender boards.
After repairing a shorted cap on the IF/audio board, I discovered that
the receiver is dead. The VFO displays "11100.0," and doesn't change.
I suspect the audio portion of the board is OK.
Any suggestions for a good place to start troubleshooting? I plan on
injecting a modulated signal at various points on the receive side of
things to see if I can isolate a particular board. I thought I'd ask
here just in case this was a common problem.
I did check the old and new list archives, followed a few tips but
they didn't pan out.
--Brian/WA3ITE
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