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FT101ZD 10M Only Incorrect Frequency Readout

 

I still have a couple of issues remaining with the "Parts" FT101ZD I'm restoring. It looks like I have a frequency counter issue. ?The counter works 100% on all bands except on any of the 10 meter band segments. ?From a cold start it reads correctly; then after about 30 seconds the readout of all 10 meter segments is 600 KHz low (e.g. 28.000 becomes 22.000). ?The actual received and transmitted frequency remains correct. ?Other than using DeOxit on the RCA connector to the counter, I've not yet gotten into it. ? I hate counter issues because I don't understand those circuits very well. ?Any ideas??
 

This sounds like an analog problem. You may be losing too much signal amplitude of the LO signal feeding the counter at the higher frequencies. Glancing over the schematic I think i would look at the buffer circuit for the input to the counter. Check the electrolytic caps around Q01, Q03, and Q04. Starting with C10.

Disclaimer, I don't own nor have I ever worked on one of these. This is an educated guess.

73

-Jim
NU0C

On Sat, 29 Jun 2024 06:14:44 -0700
"A. John Hecht via groups.io" <k6koi@...> wrote:

I still have a couple of issues remaining with the "Parts" FT101ZD I'm restoring. It looks like I have a frequency counter issue. ?The counter works 100% on all bands except on any of the 10 meter band segments. ?From a cold start it reads correctly; then after about 30 seconds the readout of all 10 meter segments is 600 KHz low (e.g. 28.000 becomes 22.000). ?The actual received and transmitted frequency remains correct. ?Other than using DeOxit on the RCA connector to the counter, I've not yet gotten into it. ? I hate counter issues because I don't understand those circuits very well. ?Any ideas?
 

Thank you Jim. That sounds very plausible. I’ll give it a try.

On Jun 29, 2024, at 15:05, Jim Shorney via groups.io <jimNU0C@...> wrote:

?
This sounds like an analog problem. You may be losing too much signal amplitude of the LO signal feeding the counter at the higher frequencies. Glancing over the schematic I think i would look at the buffer circuit for the input to the counter. Check the electrolytic caps around Q01, Q03, and Q04. Starting with C10.

Disclaimer, I don't own nor have I ever worked on one of these. This is an educated guess.

73

-Jim
NU0C

On Sat, 29 Jun 2024 06:14:44 -0700
"A. John Hecht via groups.io" <k6koi@...> wrote:

I still have a couple of issues remaining with the "Parts" FT101ZD I'm restoring. It looks like I have a frequency counter issue. The counter works 100% on all bands except on any of the 10 meter band segments. From a cold start it reads correctly; then after about 30 seconds the readout of all 10 meter segments is 600 KHz low (e.g. 28.000 becomes 22.000). The actual received and transmitted frequency remains correct. Other than using DeOxit on the RCA connector to the counter, I've not yet gotten into it. I hate counter issues because I don't understand those circuits very well. Any ideas?

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