As describe a while ago by W8NJR, also my TR-7 wouldn't lock onto frequency.
The frequency readout also showed about 17900 Khz For a while I could correct this problem by re-seating boards. However this problem came back. Measurement showed that the PTO-voltage at pin 6/38 of the translator board was zero. Re-seating of that board caused the PTO-voltage to come back to a normal value. Resoldering relevant connections on the motherboard and on the other boards did not solve the problem. Further measurements showed a short-circuit with earth at pin 6/38. The main cause for the problem, also explaining the effect of re-seating, is a short-circuit of the female part of that pin. It had "scraped through" the paint at the back side of the connector on the earth-foil of the PCB. That way it became connected with the earthplane of the PCB underneath the connector Putting a thin isolating foil between the back side of the connector and the PCB solved the problem. Apart from this problem, maybe in other cases a short-circuit underneath a connector is the secret of the solution that after re- seating things go back to normal ! The "normal" electrical contacts of the connectors indeed did not show any sign of being in a poor condition. 73, Frans PA0FVE
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