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FT-101E Signal Generator is off frequency

 

Hi,
? ?I'm new to FT-101 world but am really enjoying it.? I recently got an FT-101E and have done a lot of work getting it to work properly.? I've recapped the entire thing, performed the clarifier and tx/rx adjustment procedures, cleaned all of the internal contacts, etc.? It transmits and receives great and sounds good, so in terms of working properly, all seems to be well.? I do have a couple of minor things that I'm wondering about though.? First thing: part of the tx/rx alignment procedure is to make the voltage match between RX and TX (using Mox) with the Zero Set pot on the high voltage board.? When I read the voltages during receive and transmit, they're so far apart that the pot doesn't have enough adjustment to make them match.? I have checked TX on a separate radio, and it seems to be aligned with RX fine.? I've also made numerous stateside and DX contacts and haven't had any trouble there.? Is this a problem?? If it is, what can be done to correct it?
? ?Second, and more importantly: when I zero beat using the 25KHz or 100KHz signal generator, the frequency that I've corrected to is about 1.4KHz down from the actual frequency.? By that I mean: if I zero beat at 14.300MHz using the 100KHz signal generator, I'm actually at 14.2986MHz.? The 25KHz and 100KHz generators seem to be off by slightly different amounts too.? I have a YC-601 frequency counter so I can account for the discrepancy by calibrating the meter/dial down 1.4KHz to match the actual frequency, but I'm wondering if there's a way to adjust the signal generator to be dead on.? I haven't found any YouTube videos explaining this, and I don't see anything referencing it in the service manual.? This isn't too big of a hindrance since I know what's going on, but it would be nice to have it "right."? My assumption is that something has drifted due to age and it's something that I'll just have to get used to.
? ? Thanks in advance.

Scott
 

Since the span between LSB and USB is about 2.8KHz, I suspect your 25KHz and ?100KHz points are just about right and the error factor is probably much less than 50-100Hz off.?
And the 601 is no way as accurate as a real, but even inexpensive, frequency counter. ?
 

Plus, you have to adjust the 500KHz back dial of the VFO every time you switch from LSB, USB or CW... relative to zeroing your market generator.?
 

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Thanks?Bruce.? Something is off somewhere, I'm just not sure where.? I know that if I pull up the 14.300MHz Maritime Mobile net, I can center the VFO dial on 14.300 and hear the net fine, so I feel like the VFO and its dial are calibrated accurately (at least in USB).? If I leave the VFO on 14.300 (while tuned in on the net control) and turn on the 100KHz generator, I don't hear the tone at all.? If I move the VFO down to 14.2986 (1.4KHz down), I can zero-beat between USB and LSB there.? Shouldn't I be able to zero beat between USB and LSB at 14.300 and hear the net control on 14.300 at the same time?

Scott

From: [email protected] <[email protected]> on behalf of Bruce Collins <kb0tj1@...>
Sent: Wednesday, July 20, 2022 11:56 AM
To: [email protected] <[email protected]>
Subject: Re: [Yaesu-FT-101] FT-101E Signal Generator is off frequency
?
Plus, you have to adjust the 500KHz back dial of the VFO every time you switch from LSB, USB or CW... relative to zeroing your market generator.?

 

OK. Does your radio have the WWV receive crystal installed?
If yes, tune the receiver to it and zero beat the carrier while listening with headphones.?
Then off tune a bit so you hear a 400hz to 800hz “tone”. Don’t be confused by the modulated audio WWV also sends out. It stops occasionally so there is only a carrier.?

Now flip the marker on. ?
If close in frequency you’ll hear the difference in tone between the dead on carrier frequency of WWV and the 25KHz-100KHz crystal oscillator in your radio.?
On your regulator board (where the actual marker crystal and oscillator is located), there is TC1, a 50pF trimmer cap to adjust the marker frequency.?
If you can’t pull it in with that trimmer, you’ll need a board repair or a new marker crystal.?
Another way is to go to 160m band and see if you can use the preselector ?maxed out and tune in a local AM radio station around 1600khz to 1700khz and zero beat their carrier ... which is frequently well within 25Hz to 50Hz too.?

On Wed, Jul 20, 2022 at 10:49 AM Scott Toth <nd4l@...> wrote:
Thanks?Bruce.? Something is off somewhere, I'm just not sure where.? I know that if I pull up the 14.300MHz Maritime Mobile net, I can center the VFO dial on 14.300 and hear the net fine, so I feel like the VFO and its dial are calibrated accurately (at least in USB).? If I leave the VFO on 14.300 (while tuned in on the net control) and turn on the 100KHz generator, I don't hear the tone at all.? If I move the VFO down to 14.2986 (1.4KHz down), I can zero-beat between USB and LSB there.? Shouldn't I be able to zero beat between USB and LSB at 14.300 and hear the net control on 14.300 at the same time?

Scott
From: [email protected] <[email protected]> on behalf of Bruce Collins <kb0tj1@...>
Sent: Wednesday, July 20, 2022 11:56 AM
To: [email protected] <[email protected]>
Subject: Re: [Yaesu-FT-101] FT-101E Signal Generator is off frequency
?
Plus, you have to adjust the 500KHz back dial of the VFO every time you switch from LSB, USB or CW... relative to zeroing your market generator.?

 

Your three local oscillator crystals, USB LSB CW.... ?could be off frequency too.?

On Wed, Jul 20, 2022 at 10:49 AM Scott Toth <nd4l@...> wrote:
Thanks?Bruce.? Something is off somewhere, I'm just not sure where.? I know that if I pull up the 14.300MHz Maritime Mobile net, I can center the VFO dial on 14.300 and hear the net fine, so I feel like the VFO and its dial are calibrated accurately (at least in USB).? If I leave the VFO on 14.300 (while tuned in on the net control) and turn on the 100KHz generator, I don't hear the tone at all.? If I move the VFO down to 14.2986 (1.4KHz down), I can zero-beat between USB and LSB there.? Shouldn't I be able to zero beat between USB and LSB at 14.300 and hear the net control on 14.300 at the same time?

Scott
From: [email protected] <[email protected]> on behalf of Bruce Collins <kb0tj1@...>
Sent: Wednesday, July 20, 2022 11:56 AM
To: [email protected] <[email protected]>
Subject: Re: [Yaesu-FT-101] FT-101E Signal Generator is off frequency
?
Plus, you have to adjust the 500KHz back dial of the VFO every time you switch from LSB, USB or CW... relative to zeroing your market generator.?

 

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This is great info, thanks!? I just tried to adjust it with the trimmer pot, and I could get it sorta close as long as the screw driver was on the pot, but as soon as I took it away, the marker tone changed significantly.? I can't get it close enough to be accurate, so I guess my next option is to try and find a replacement marker crystal and see where that gets me.? I'll do some research to see if any are still available.? I appreciate this a lot- definitely gets me much closer to having this problem resolved!

Best,
?? Scott


On 7/20/2022 1:48 PM, Bruce Collins wrote:

OK. Does your radio have the WWV receive crystal installed?
If yes, tune the receiver to it and zero beat the carrier while listening with headphones.?
Then off tune a bit so you hear a 400hz to 800hz “tone”. Don’t be confused by the modulated audio WWV also sends out. It stops occasionally so there is only a carrier.?

Now flip the marker on. ?
If close in frequency you’ll hear the difference in tone between the dead on carrier frequency of WWV and the 25KHz-100KHz crystal oscillator in your radio.?
On your regulator board (where the actual marker crystal and oscillator is located), there is TC1, a 50pF trimmer cap to adjust the marker frequency.?
If you can’t pull it in with that trimmer, you’ll need a board repair or a new marker crystal.?
Another way is to go to 160m band and see if you can use the preselector ?maxed out and tune in a local AM radio station around 1600khz to 1700khz and zero beat their carrier ... which is frequently well within 25Hz to 50Hz too.?

On Wed, Jul 20, 2022 at 10:49 AM Scott Toth <nd4l@...> wrote:
Thanks?Bruce.? Something is off somewhere, I'm just not sure where.? I know that if I pull up the 14.300MHz Maritime Mobile net, I can center the VFO dial on 14.300 and hear the net fine, so I feel like the VFO and its dial are calibrated accurately (at least in USB).? If I leave the VFO on 14.300 (while tuned in on the net control) and turn on the 100KHz generator, I don't hear the tone at all.? If I move the VFO down to 14.2986 (1.4KHz down), I can zero-beat between USB and LSB there.? Shouldn't I be able to zero beat between USB and LSB at 14.300 and hear the net control on 14.300 at the same time?

Scott
From: [email protected] <[email protected]> on behalf of Bruce Collins <kb0tj1@...>
Sent: Wednesday, July 20, 2022 11:56 AM
To: [email protected] <[email protected]>
Subject: Re: [Yaesu-FT-101] FT-101E Signal Generator is off frequency
?
Plus, you have to adjust the 500KHz back dial of the VFO every time you switch from LSB, USB or CW... relative to zeroing your market generator.?

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