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Another TR-3 s/n 1329

 

I find myself with another TR-3 that I was not expecting.

I arrived at my Hamvention booth Saturday morning to find a TR-3 sitting there.
A fellow booth person who is local to Dayton brought it to me and said $50.
I wasn't looking for one but said OK.
He said he hasn't looked at it in about 15 years and remembers that it does not work.

I have confirmed that it does not work!

At least no snap, crackle, pop or smoke when powered up.

Tubes and meter lights do light up.
Audio is low to start and after 5 minutes there is almost no audio.
No change in noise when the RF tune knob is rotated on any band.
RF gain does work and s meter responds higher as gain is turned down.
When put in CAL position there is a constant low frequency tone everywhere on any band.
No RX signals anywhere even with my TS590 at 100 watts into a dummy load sitting next to it.

When put in X-SSB to tune there is no plate current on any band.

I am using the same power supply as I do with my other TR-3 so that should be OK.

Time to open it up and look at the tubes first and go from there.

Your thoughts, suggestions and guidance are appreciated as always.


Dave,

KC3AM
 

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Dave,

is the RV3 jumper plug with pins 2 and 8 shorted, plugged into the
bottom of the TR3's RV3 socket? Some TR3s have a solid wire
soldered to pins 2 and 8 with the wire routed across the female
side of the RV3 socket. I removed that wire then made up a
jumper plug with pins 2 and 8 shorted together.

Check at C145B and R111 for +250VDC LV.

Check pin 1 of V20 OA2 for +150VDC.

Loss of either those 2 voltages and the missing RV3 jumper plug
with pins 2 and 8 shorted will result in no receive and no transmit
and a constant low level tone with the Calibrator turned ON and no
zero beat tone at 100Khz dial intervals when tuning the VFO.

Also, check for broken wires on the RV3 socket on the bottom of
the TR3. You will have to remove the 2 long sheet metal screws
and hollow metal supports to rotate the RV3 socket to check for
broken wires. I found 2 broken/missing wires in my TR3 on the RV3
socket.

73
Mike W5RKL



On 5/21/25 3:32 PM, Dave Stepnowski KC3AM via groups.io wrote:

I find myself with another TR-3 that I was not expecting.

I arrived at my Hamvention booth Saturday morning to find a TR-3 sitting there.
A fellow booth person who is local to Dayton brought it to me and said $50.
I wasn't looking for one but said OK.
He said he hasn't looked at it in about 15 years and remembers that it does not work.

I have confirmed that it does not work!

At least no snap, crackle, pop or smoke when powered up.

Tubes and meter lights do light up.
Audio is low to start and after 5 minutes there is almost no audio.
No change in noise when the RF tune knob is rotated on any band.
RF gain does work and s meter responds higher as gain is turned down.
When put in CAL position there is a constant low frequency tone everywhere on any band.
No RX signals anywhere even with my TS590 at 100 watts into a dummy load sitting next to it.

When put in X-SSB to tune there is no plate current on any band.

I am using the same power supply as I do with my other TR-3 so that should be OK.

Time to open it up and look at the tubes first and go from there.

Your thoughts, suggestions and guidance are appreciated as always.


Dave,

KC3AM







 

Dave,
There's a jumper on the remote VFO connector on the bottom of the radio that is cut to enable the radio to work with the remote VFO.? Make sure that jumper is still there.? It should be under the connector between two pins.? I don't remember which pins but if you have a manual look at the section about using the radio with the remote VFO and it explains it.? Your symptoms sound similar to how the radio will (not) work without that jumper.?

Barry
KJ5GQM

On Wednesday, May 21, 2025 at 03:33:04 PM CDT, Dave Stepnowski KC3AM via groups.io <kc3am@...> wrote:


I find myself with another TR-3 that I was not expecting.

I arrived at my Hamvention booth Saturday morning to find a TR-3 sitting
there.
A fellow booth person who is local to Dayton brought it to me and said $50.
I wasn't looking for one but said OK.
He said he hasn't looked at it in about 15 years and remembers that it
does not work.

I have confirmed that it does not work!

At least no snap, crackle, pop or smoke when powered up.

Tubes and meter lights do light up.
Audio is low to start and after 5 minutes there is almost no audio.
No change in noise when the RF tune knob is rotated on any band.
RF gain does work and s meter responds higher as gain is turned down.
When put in CAL position there is a constant low frequency tone
everywhere on any band.
No RX signals anywhere even with my TS590 at 100 watts into a dummy load
sitting next to it.

When put in X-SSB to tune there is no plate current on any band.

I am using the same power supply as I do with my other TR-3 so that
should be OK.

Time to open it up and look at the tubes first and go from there.

Your thoughts, suggestions and guidance are appreciated as always.


Dave,

KC3AM
 

开云体育

The RV3 socket pins that need to be connected when the RV3 is not plugged into the
"J2" on the bottom of the TR3, are pins 2 and 8. Look at the TR3 schematic, J2 clearly
shows the dotted lines between pins 2 and 8. Those dotted lines represent the
male plug with pins 2 and 8 shorted together. I've seen a jumper wire connected between
pins 2 and 8 on the female socket with the wire routed over the female socket. Don't know
who came up with that idea but I removed it from my TR3. I use an 8 pin jumper plug with
pins 2 and 8 shorted when my RV3 is not plugged into the bottom of the TR3.

Shorting pin 2 to 8, pin 8 is "ground", turns the TR3 VFO "ON". Without the jumper the VFO
doesn't work.

73
Mike W5RKL

On 5/21/25 3:47 PM, Barry KJ5GQM via groups.io wrote:

Dave,
There's a jumper on the remote VFO connector on the bottom of the radio that is cut to enable the radio to work with the remote VFO.? Make sure that jumper is still there.? It should be under the connector between two pins.? I don't remember which pins but if you have a manual look at the section about using the radio with the remote VFO and it explains it.? Your symptoms sound similar to how the radio will (not) work without that jumper.?

Barry
KJ5GQM

On Wednesday, May 21, 2025 at 03:33:04 PM CDT, Dave Stepnowski KC3AM via groups.io <kc3am@...> wrote:


I find myself with another TR-3 that I was not expecting.

I arrived at my Hamvention booth Saturday morning to find a TR-3 sitting
there.
A fellow booth person who is local to Dayton brought it to me and said $50.
I wasn't looking for one but said OK.
He said he hasn't looked at it in about 15 years and remembers that it
does not work.

I have confirmed that it does not work!

At least no snap, crackle, pop or smoke when powered up.

Tubes and meter lights do light up.
Audio is low to start and after 5 minutes there is almost no audio.
No change in noise when the RF tune knob is rotated on any band.
RF gain does work and s meter responds higher as gain is turned down.
When put in CAL position there is a constant low frequency tone
everywhere on any band.
No RX signals anywhere even with my TS590 at 100 watts into a dummy load
sitting next to it.

When put in X-SSB to tune there is no plate current on any band.

I am using the same power supply as I do with my other TR-3 so that
should be OK.

Time to open it up and look at the tubes first and go from there.

Your thoughts, suggestions and guidance are appreciated as always.


Dave,

KC3AM
 

I had a constant tone when I engaged the Calibrator in my TR-4. It can be caused by the carrier oscillator not being set properly.

Barry - N4BUQ

I find myself with another TR-3 that I was not expecting.

I arrived at my Hamvention booth Saturday morning to find a TR-3 sitting
there.
A fellow booth person who is local to Dayton brought it to me and said $50.
I wasn't looking for one but said OK.
He said he hasn't looked at it in about 15 years and remembers that it
does not work.

I have confirmed that it does not work!

At least no snap, crackle, pop or smoke when powered up.

Tubes and meter lights do light up.
Audio is low to start and after 5 minutes there is almost no audio.
No change in noise when the RF tune knob is rotated on any band.
RF gain does work and s meter responds higher as gain is turned down.
When put in CAL position there is a constant low frequency tone
everywhere on any band.
No RX signals anywhere even with my TS590 at 100 watts into a dummy load
sitting next to it.

When put in X-SSB to tune there is no plate current on any band.

I am using the same power supply as I do with my other TR-3 so that
should be OK.

Time to open it up and look at the tubes first and go from there.

Your thoughts, suggestions and guidance are appreciated as always.


Dave,

KC3AM
 

开云体育

The TR3's 100Khz calibrator signal can be checked at pin 1 of V7.
If your scope can display the frequency of the signal, connect the
scope probe (probe initially set to x10) to pin 1 of V7. Turn the calibrator
ON and if the calibrator signal is there, the scope should display
the sine wave and 100Khz frequency. If the signal at pin 1 of V7 is low,
switch the probe to x1.

I found my TR3's calibrator top be right on 100Khz.

Loss of receiver quite often is caused by the VFO not working.
My TR3 had no receive and with the calibrator turned ON, I heard
a very low level tone (SIDE BAND set to "X"). That tone did not
change when tuning the TR3's VFO.

Measure the voltage at the positive terminal of? C145B (see picture below).
There should be "+250VDC". If you don't see +250VDC at C145B
positive terminal, check R111 3.3K 1/2W resistor. R111 connects between
the top of the 2 small PC board to the right of can capacitor C145 and next
to the audio transformer. R111 is 3.3K 1/2W, color band Orange/Orange/Red
with Silver 10% tolerance. If R111 is open then there will be no B+ to
V16 6GX6 (Product Detector/BFO oscillator) and to both stages of V18. Lost
of +250VDC to the Product Detector/BFO oscillator will result in loss of
receive.

Measure voltage at C145A, you should see regulated +150VDC (see location
of C145A in the picture below).

73
Mike W5RKL






On 5/21/25 4:28 PM, n4buq via groups.io wrote:

I had a constant tone when I engaged the Calibrator in my TR-4.  It can be caused by the carrier oscillator not being set properly.

Barry - N4BUQ


I find myself with another TR-3 that I was not expecting.

I arrived at my Hamvention booth Saturday morning to find a TR-3 sitting
there.
A fellow booth person who is local to Dayton brought it to me and said $50.
I wasn't looking for one but said OK.
He said he hasn't looked at it in about 15 years and remembers that it
does not work.

I have confirmed that it does not work!

At least no snap, crackle, pop or smoke when powered up.

Tubes and meter lights do light up.
Audio is low to start and after 5 minutes there is almost no audio.
No change in noise when the RF tune knob is rotated on any band.
RF gain does work and s meter responds higher as gain is turned down.
When put in CAL position there is a constant low frequency tone
everywhere on any band.
No RX signals anywhere even with my TS590 at 100 watts into a dummy load
sitting next to it.

When put in X-SSB to tune there is no plate current on any band.

I am using the same power supply as I do with my other TR-3 so that
should be OK.

Time to open it up and look at the tubes first and go from there.

Your thoughts, suggestions and guidance are appreciated as always.


Dave,

KC3AM

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