TRAM D201 non hand wired questions.

[Crambone]

Unit receives good on AM/ LSB & USB, TX on AM dead key 4 watts but not much swing on Modulation at first swings from 4 watts to around 15 watts but after a second only goes 4 - 7 watts. LSB & USB 0 - 15 watts so that fine.
I checked and swapped all the tubes, recapped all electrolytic and HV resistors. Still same issue after trying various tubes and changing caps and resistors. The meter also isn’t working it pegs left only time it seems to work at all is cal swr.
i haven’t aligned it yet I’m looking for a copy of the SAMS for it? I do have the manual but would prefer the SAMS.
I do the alignment based on the manual what order should I start the alignment?
Any suggestions appreciated.

 

[nomadradio]

The meter in that radio reads the current balance (and imbalance) between one section of V401, back by the relay inside a shield, and one section of V602, the one closest to the 6L6 audio tube. If one of these two tubes has a stronger triode section than the other tube, the zero trimpot won't achieve a zero setting. Try swapping those two 6GH8 tubes one for the other. If the meter now pegs in the opposite direction, and the trimpot still won't take it to a zero setting, those two 6GH8 tubes are hopelessly unmatched. There are three other tubes with that type number in the radio. Good chance that out of five tubes you'll have one pair that matches closely enough to make the meter behave itself.

Could be a bad zero trimpot R422.

73

 

[Crambone]

The meter in that radio reads the current balance (and imbalance) between one section of V401, back by the relay inside a shield, and one section of V602, the one closest to the 6L6 audio tube. If one of these two tubes has a stronger triode section than the other tube, the zero trimpot won't achieve a zero setting. Try swapping those two 6GH8 tubes one for the other. If the meter now pegs in the opposite direction, and the trimpot still won't take it to a zero setting, those two 6GH8 tubes are hopelessly unmatched. There are three other tubes with that type number in the radio. Good chance that out of five tubes you'll have one pair that matches closely enough to make the meter behave itself.

Could be a bad zero trimpot R422.

73

Thanks I will test the 6GH8’s and find the closest matched I can. I did remove and check R422 and it tested good.

 

[Crambone]

The meter in that radio reads the current balance (and imbalance) between one section of V401, back by the relay inside a shield, and one section of V602, the one closest to the 6L6 audio tube. If one of these two tubes has a stronger triode section than the other tube, the zero trimpot won't achieve a zero setting. Try swapping those two 6GH8 tubes one for the other. If the meter now pegs in the opposite direction, and the trimpot still won't take it to a zero setting, those two 6GH8 tubes are hopelessly unmatched. There are three other tubes with that type number in the radio. Good chance that out of five tubes you'll have one pair that matches closely enough to make the meter behave itself.

Could be a bad zero trimpot R422.

73

Ok matched a set and that did it but it takes a long time to settle in. Pegs far right then very, very, very slowly comes down, about 10 minutes.
now that that was kind of fixed I wanted to tackle the next issue. So I figured I would start at the Trouble Shooting and Alignment.
SYNTHESIZER PIN VOLTAGE CHART.
Found some bad voltages specifically to Pin 1 & 6
Pin 1 in RX & TX tests shows 0vdc when 1.5vdc is specified.
Pin 6 shows 11.5vdc no matter what in RX or TX should only show 2.3vdc.
Uhhhh where to start?

 

[nomadradio]

Pin 1 is the clarifier's counterclockwise (left extreme) lug. The voltage here is set by trimpot R145. To maximize the clarifier's range, this trimpot will be set to zero Volts. Pin 6 should have nowhere near 11.5 Volts on it. Very odd.

73

 

[Crambone]

Pin 1 is the clarifier's counterclockwise (left extreme) lug. The voltage here is set by trimpot R145. To maximize the clarifier's range, this trimpot will be set to zero Volts. Pin 6 should have nowhere near 11.5 Volts on it. Very odd.

73

Thanks Nomad I got the Pin 1 issue completed now I’m going to look for the Pin 6 issue. I see it runs to the Cal pull/ push switch and it looks like it’s been messed with so I’m going to follow the wires just wish I had a good schematic for this D201.

 

[Crambone]

Pin 1 is the clarifier's counterclockwise (left extreme) lug. The voltage here is set by trimpot R145. To maximize the clarifier's range, this trimpot will be set to zero Volts. Pin 6 should have nowhere near 11.5 Volts on it. Very odd.

73

Got back to it yesterday and found a short across Q103 drain and supply. Voltage down from 11.5 to 1.8 With a used 2N5485, ordered a new one as I should see 2.5vdc I am getting the 12.5 dc on the other end.
I proceeded by checking some of the Synthesizer board frequencies using a frequency counter and spectrum analyzer for comparison
1) Synthesizer Pin voltages all ok now
2) 4 MHz Calibration dead on now
3) +++20MHz Calibration is giving a problem C126-137 show no change in frequency when adjusting.
4) 20MHz Mixer is peaked

going to test components today hoping to find something open or shorted.

 

[nomadradio]

C126-137 show no change in frequency when adjusting.

Naturally you have to select the correct channel and mode for each of those trimmers. One fault we see repeatedly is for the moveable ceramic disc on these trimcaps to seize. There is a thin flexible washer between the disc and the body of the trimcap. The washer will degrade and become adhesive, seizing the disc to the body. Putting enough torque onto the screw slot will free it with a loud "crack!". That's the sound of the solder bond being broken between the screw head and the metal layer on the disc. The screw now turns freely, but the disc that forms the moveable half of the capacitor remains seized in place. If someone ahead of you has 'cracked' all the trimcaps loose already, turning them will have negligible influence on the frequency of the crystal that each one controls.

A bright light and a magnifier will reveal if the whole body of the trimcap's disc is turning along with the screw head. If the solder bond is broken, this should be visible from up close.

73

 

[Crambone]

Naturally you have to select the correct channel and mode for each of those trimmers. One fault we see repeatedly is for the moveable ceramic disc on these trimcaps to seize. There is a thin flexible washer between the disc and the body of the trimcap. The washer will degrade and become adhesive, seizing the disc to the body. Putting enough torque onto the screw slot will free it with a loud "crack!". That's the sound of the solder bond being broken between the screw head and the metal layer on the disc. The screw now turns freely, but the disc that forms the moveable half of the capacitor remains seized in place. If someone ahead of you has 'cracked' all the trimcaps loose already, turning them will have negligible influence on the frequency of the crystal that each one controls.

A bright light and a magnifier will reveal if the whole body of the trimcap's disc is turning along with the screw head. If the solder bond is broken, this should be visible from up close.

73

Ahh yes I’ve encountered that on a Yaesu FT-101E years ago, thanks for the reminder.