Yaesu FT221 problem with alignment

[ontheedgeandy]

Hi People hope your all staying safe, I've recently bought a ft 221 of a local ham, however it turns out he has sold me a dud, so I've been fiddling and changing all the old capacitors etc that I could find that were bad, I've managed to got through the alignment procedure as per the service manual bbut I'getting stuck when setting the capcitor voltages via the marker board , I can get bands 144 through to 145.5 working and can clearly hear to marker tone but as soon as I select 146 or bands above that the marker tone is no longer heard anyone any idea where too look next . Best regards Andrew M6YYD

[Radio Wrangler]

It may be working fine. The 2 metre band above 146MHz isn't assigned to Europe, so it is likely to not have the crystals fitted for those bands. Those bands only make sense in models sold in the US.

David

[Oldmadham]

Or Australia, or New Zealand, or Canada, or virtually anywhere else which isn't in Europe.

73, VK6ZGO

[Radio Wrangler]

Because of the price differentials across global markets, we've had a lot of radios bought in the US coming into the UK. So I keep coming across US variants of various radios.

I assume that Australia and NZ suffer whomped-up prices like we do and there is no financial incentive of the same order. I did once have an IC-761 apart that had come from Australia, but it turned out it had been bought in America originally and blown up in Australia because someone didn't know how to change the voltage setting in the SMPS (there is a bridging link hidden UNDER the bridge rectifier!)

David

[ontheedgeandy]

Wow amazing guys just looked at the schematic and sure enoug the Crystal's are shown in the local oscillator but missing in the radio itself which explains why the bands above 146000 are missing.

However I have one more problem to solve as when I switch from to band 145.500 sometimes it receives but when I move back and forth between the bands or turn the radio on or off it stops receiving on that band only, and only starts receiving again when I switch back and forth between bands in a certain order again, tried cleaning the band switch but to no avail

[ontheedgeandy]

Too add if I turn the radio off then on again that band dosen't work until you move the band switch to another band and then back, it does this consistently.

[Radio Wrangler]

Crystal oscillators can become a bit iffy about starting up and need a bit of choke in the morning. A cure might involve a bit of value adjustment in the oscillator circuit to give them a bit more gain.

David

[ontheedgeandy]

Hi David.

Thanks for the response.

Would you adjust the variable caps on the same board? or would you do something else? Would it be down to crystal age as the set is very old.

Best regards M6YYD.

[Radio Wrangler]

No, not the variable capacitors, they are to trim the frequency.

Putting up the quiescent current in the oscillator transistor by about 10% would be a good first trial.

David

[ontheedgeandy]

thanks for that i think ive done it right now

looks like ive nailed it now as the marker board has the Variable resistors for each of the bands to adjust the capacitance voltage for the different crystals adjusted the one for the band in question and away we go no drop outs as of yet,

tweaked the radio in via the marker board, replaced quite a few capacitors including some split mylar capacitors, cleaned the switches and board connections, and seems to be ive got quite a nice radio hear now

what i would like to do is check the receive performance is ther any way to do this without a signal generator?

best regards M6YYD

[Jon_G4MDC]

Those crystals are in a Variable Crystal Oscillator (VXO) making the RIT circuit. It's common that they run or stop depending on the setting of the RIT control.

It's not certain that the problem is the crystals failing to oscillate. They feed a PLL circuit which can be reluctant to lock and give the same symptom of muted audio, no TX & flashing S meter light.

TP03 on the LOCAL Board is a diode probe at the output of the crystal oscillator multiplier. You could check for Voltage there to see whether it is the oscillator failing to start.

[ontheedgeandy]

yes when it didnt work the voltage at tp301 dropped on the pll board it was a combination of adjusting the variable capacitor on the pll and and variable resistor to get it to lock then i had to adjust the vr on the marker board to bring up the receive to peak.

i think im doing all this right dont really understand it properley but all is good still now, just not sure if the receive sensitivity is ok

regards M6YYD

[Jon_G4MDC]

TP301 is the tuning line of the PLL. The Voltage there will change fairly slowly as you vary the main tuning dial. It will change in steps as you move between 500kHz bands. When out of lock it will probably settle very high or very low in Voltage depending on the reason.

To check the crystals oscillate you do need to be looking at TP03 of the local board. Wish you luck with it.

[M0AFJ, Tim]

Originally Posted by ontheedgeandy

thanks for that i think ive done it right now

looks like ive nailed it now as the marker board has the Variable resistors for each of the bands to adjust the capacitance voltage for the different crystals adjusted the one for the band in question and away we go no drop outs as of yet,

tweaked the radio in via the marker board, replaced quite a few capacitors including some split mylar capacitors, cleaned the switches and board connections, and seems to be ive got quite a nice radio hear now

what i would like to do is check the receive performance is ther any way to do this without a signal generator?

Hi, depending on what antenna you have you should be able to the the beacon GB3VHF on 144.430 if you receiver is working well, you may not hear it on a vertical though.
Best 73 Tim M0AFJ

[ontheedgeandy]

Thanks for all this great info still all good so far just dont understand the marker tone for zero beat(but theres only one peak and not two with an obvious middle position} should i be listening for the highest pitch sound not sure any help would be amazing allready begining to love this radio

best regards Andy

[Jon_G4MDC]

It's good there's tone only on one side of zero beat with an SSB radio. It means your unwanted sideband suppression is good.

Zero beat is the position where the tone is zero frequency. Sometimes you can just hear a slow flutter in the noise - that's a beat of just a few Hz or less.

On a 221 the dial calibration of zero beat changes between USB and LSB. Thats why the button below and left of tuning dial. If you haven't found it yet it's a clutch which grips the circular scale to adjust cal after mode changes. Calibrate it on USB since LSB is almost never used except with some transverters etc. On AM and FM an error of 1kHz in the cal is hardly serious - probably leave it alone on those modes. I do.

[ontheedgeandy]

thanks for that, ive made abit of a boo boo, ive replaced all the elctrolytic caps on the mic amp unit and now the audio is quiet and the radio keys itself after a given time or if you key the radio after a given time it gets stuck in transmit mode , tried the relay im guessing its the mic amp board as ive just wroked on that and it was fine before, except for the old electrolytics, hopefully someone might be able to point me in the right direction lol
best regards Andy M6YYD

[ontheedgeandy]

ok well i cured it sticking transmitting by calibrating the vfo as it was quite a way off, but still the mic audio is very quiet with the mic gain turned all the way up

[ontheedgeandy]

It's still locking in transmit ������

[Jon_G4MDC]

You have probably upset the VOX circuit somehow. Sticking on TX can't be affected by VFO calibration. Make sure VOX gain control to the left of S meter is pointing to PTT position i.e. just before the switch clicks at max anticlockwise rotation.