I have a TR7A that is very weak on receive and will not transmit. The +10T
and +10R lines operate normally when PTT is selected and I press the mic
switch. All receive functions seem to work correctly, but the receive signal
level for even very strong signals is too low to produce any AGC action. If
I back off on the RF gain the S meter does register, so it doesn't look like
an AGC problem. The -5 volt line is only -3.something, but the +24 line and
+10 supply are within specs. The output of the multivibrator / bridge
rectifier for the +24V is within spec as well.

If anyone has seen this kind of problem and can tell me where to start
looking, I would appreciate it.

73,
Bob AD3K

"Bob Spooner" wrote in message
...
I have a TR7A that is very weak on receive and will not
transmit. The +10T and +10R lines operate normally when PTT
is selected and I press the mic switch. All receive
functions seem to work correctly, but the receive signal
level for even very strong signals is too low to produce
any AGC action. If I back off on the RF gain the S meter
does register, so it doesn't look like an AGC problem.
The -5 volt line is only -3.something, but the +24 line and
+10 supply are within specs. The output of the
multivibrator / bridge rectifier for the +24V is within
spec as well.

If anyone has seen this kind of problem and can tell me
where to start looking, I would appreciate it.

73,
Bob AD3K
I'm not familiar with the TR-7 but the one area that is
certainly common to both receive and transmit is the antenna
switching circuit. Perhaps its stuck in some way so that
neither the receiver or transmitter is being connected to
the antenna.


--

--
Richard Knoppow
Los Angeles
WB6KBL

Hi,

I'm not familiar with that radio either, but if your -5V line is 2 volts
low, there is either:

- Power supply fault.
- Something is loading it down.

If it's modular, try disconnecting the boards one by one until the -5V
comes back up. That'll track it to a module at least.

Cheers!

Drake is still in Business. Contact them. they may still
service the TR7.
stan
I have a TR7A that is very weak on receive and will not transmit. The +10T
and +10R lines operate normally when PTT is selected and I press the mic
switch. All receive functions seem to work correctly, but the receive
signal level for even very strong signals is too low to produce any AGC
action. If I back off on the RF gain the S meter does register, so it
doesn't look like an AGC problem. The -5 volt line is only -3.something,
but the +24 line and +10 supply are within specs. The output of the
multivibrator / bridge rectifier for the +24V is within spec as well.

If anyone has seen this kind of problem and can tell me where to start
looking, I would appreciate it.

73,
Bob AD3K

On Mon, 8 Dec 2008 20:13:59 -0800, "Stanley Miln"
wrote:

Drake is still in Business. Contact them. they may still
service the TR7.
stan
I have a TR7A that is very weak on receive and will not transmit. The +10T
and +10R lines operate normally when PTT is selected and I press the mic
switch. All receive functions seem to work correctly, but the receive
signal level for even very strong signals is too low to produce any AGC
action. If I back off on the RF gain the S meter does register, so it
doesn't look like an AGC problem. The -5 volt line is only -3.something,
but the +24 line and +10 supply are within specs. The output of the
multivibrator / bridge rectifier for the +24V is within spec as well.

If anyone has seen this kind of problem and can tell me where to start
looking, I would appreciate it.

73,
Bob AD3K



No,
Drake stopped servicing all Amateur Radio products about 4 years ago
and sold off the parts inventories.

I'd check and see why that 5 volt line is low or what is pulling the
supply line low.

Doug/WA1TUT