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There is a possible differance among the TR-7/TR-7A, the RV-75, and the 4310.? My 4310 has a feature not present in the other gear. ? When using the RIT, if the main PTO is changed it automatically turns off the RIT.? I don't know if this is the case for all 4310s or not.

Evan, K9SQG

On Friday, April 11, 2025 at 11:02:18 PM EDT, Gary Follett via <xntrick1948=[email protected]> wrote:

The TR4310 is the same as a TR7 in virtually every way. It uses a PTO as a reference for the two VCO’s, one for the bands below 14 MHz and a second one for the higher bands. The chirping you are hearing is the VCO trying to seek a lock.

You should also see the digital frequency display ramping up as the radio goes through this process.

First question-does it do this on low bands and high bands as well?

If you have an oscilloscope, you can have a look at the PTO output to see if it is missing when the radio is cold. No amount of drift in the PTO will cause the lock-seeking condition you experience, so all you need to confirm is that the PTO signal is present. However, total absence of the PTO signal will produce the problem you are having.

The most common cause of synthesizer lock problems is the condition of the switches that control which PTO is in use (internal, RV7, RV75 etc.), and also the “Fixed” switches. A quick spray with contact cleaner should fix this.

Also, the rotary switch that controls the AUX7 function can also cause the problem. Again, a spray with cleaner should tidy things up.

Whenever spraying a switch, immediately operate the switch through all positions quickly several times to complete the cleaning process.

Gary?

W0DVN

On Apr 11, 2025, at 4:59?AM, Tilman SM0JZT via <sm0jzt=[email protected]> wrote:

?

Mark

Thank you so VERY much for the quick and detailed response.?
I will print your response out and go through one by one.?

B.r / Tilman SM0JZT