The filter is in the RX IF stage, it has nothing to do with transmission.
Are you sure you didn't disturb something else?
Brian.
All the XF filters (including XF90C) are used on both, RX and TX.
In TX SSB mode, the DSB signal from the DSB modulator (D503, 504, 505 506) is going to the gate of the source follower Q403, and from there (through D405) exit the PB-1436C IF unit on pin 14 (RX IN/TX OUT), and from there to pin 17 of the Filter Unit (PB-1435). After filtering, the TX signal exit the filter unit on pin 6 (TX out).
In CW mode the DSB modulator is not used. The IF 9MHz CW signal is generated by CW OSC Q409, and after that is using the same source folower as the SSB path (Q403). From Q403 (the same as in SSB) the CW signal goes to the Filter Unit (pin 17).
If the TX power is low in CW, have to check using a scope the signal path in CW and maybe compare the levels to SSB path.
If the levels are the same (SSB and CW) at pin 17 of the filter unit, could be something wrong with the new filter (higher insertion loss, which you may not notice in RX mode).
Or the central frequency of the new XF90C doesn't match the CW carrier frequency (Q409).
Or the central frequency of the new XF90C doesn't match the CW carrier frequency (Q409).
Sorry for my misinformation about being RX only. I've been hospitalized for a while with only my mobile phone so reading Yaesu schematics hasn't been easy!
It seems either the filter is slightly off frequency or more likely the CW oscillator has drifted over the years. Anyway, it seems fixed so 'well done!'.
Brian.
The CW OSC signal is not going in other place. The Digital Display Circuit is using a different crystal reference oscillator.
The reason that you get a bit less power in CW (80W instead 100W) is because CW filters usually have a bit more insertion loss than SSB or AM ones (1dB up to 3dB more).
Yaesu should compensate somehow for this loss on TX path, but this is a very old transceiver, which otherwise it has a pretty quiet receiver.
Wish good health to everybody on this forum...
I mention "old solid-state radios", because also the old tube-radios were noisier than an "all dual-gate MOSFET" receiver.
I really wish it was Covid19! It's cancer I'm afraid.Brian, I hope it was not covid19. Either way, I wish you good luck with your health man!
I really wish it was Covid19! It's cancer I'm afraid.
Actually I was quite lucky, the hospital stopped all admissions the day after I left so it could be prepared to take Covid19 patients.
Brian.
Thanks for your good wishes Kostas.
I was diagnosed just over a year ago but this last trip was for biopsy to see how far it has spread. Too many needles for my liking!
I'm OK, still functioning normally but a little uncomfortable. Hopefully I've got a few years left to go!
On a plus point - I now know a lot more about anatomy... and how MRI scanners work!
Brian.
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