H Mark,
Have you adjusted upper and lower sideband frequency. These xtals typically drift out of spec. adjusting the frequency pot will typically not get you there.
If you need parts I have plenty of them.
You’ll need a good spectrum analyzer or sensitive frequency counter to measure xtal freq. Also the SSB filters drift(xtal based). I’ll need to sweep them to see how far of they are.
Verify supply voltages, see schematic for voltages.
Let me know if you need more details.
Michael
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On Jan 29, 2024, at 7:52?PM, atlasstuff <g4fph@...> wrote:
?Hi to all in the group!
I have started to repair an FT-301 that I acquired years ago. Must say I am mightily impressed with how Yaesu built these. Just love the plug-in card system - must surely be a candidate for the easiest radio to get into and fix ever made.
So far, I have it working on receive - and sounding nice. On transmit, and without the booster plugged in on the rear panel, it produces up to 20 W of RF in SSB, but only a disappointing 1 W of RF in CW / FSK / AM. Sadly, the booster has suffered some mechanical damage in that the 'Jones' plug has taken a bash and the paxolin on the rear that retains the pins now doesn't. Might end up having to replace the whole plug.
A couple of questions, if I may:
Q1. Should the impedance of the companion hand microphone be 50 kOhm, or 500 Ohm? I thought I had read somewhere that, like the FT-101 up until the E/F, the microphone should be a Hi-Z type. I have both types here, but the 50 kOhm unit does not drive the '301 TX at all, whereas the 500 Ohm one does with gusto.
Q2. The front panel meter on mine is open circuit. The circuit shows it as a 200 uA FSD unit. Does anyone have experience of taking one apart and making a fix, or am I looking at finding a (unobtanium) replacement?
Regards,
Mark, G4FPH.
Michael K.