开云体育

Yaesu FT101ZD Slow rising output only on 40M!

PA3DAF All Messages By This Member #534 Hello to you all, ? ? ? Recently I bought a Yaesu FT101ZD MK3. It needed a lot of cleaning and was “deaf” due to a blown J310 in the RF unit but everything works fine now except for a strange slow power increase on 40M. I can tune the transceiver to maximum power but it takes about 10 seconds before the output is at its max. When I release the PTT, wait for a few seconds and go back to transmit I have instant full power BUT when I wait for a minute or longer the output power starts at about 25 Watts and slowly (10 seconds) climbs to full power. This happens only on 40M!! I checked and rechecked everything but can’t find anything wrong: - All (HV) voltages OK, changed all HV caps, no change. - Output from the RF unit is stable. - Output on the “rf-out” jack on the back is stable. - Changed driver and PA tubes from my FT902, no change. - Bandswitch is cleaned and all contacts checked with ohm meter. - T/R relay OK. - Aligned the trimmerboards for 40M, no change. - All bands 100W output, 80-90W on 10m. - No ALC indication on the meter. - Checked for cold solder joints in driver and PA unit. The output at the "RF OUT" jack is nice and steady so I suspected that there is something wrong with the (40M) C trimmer board or with a 40M only component in the PA tank circuit. I checked and changed C107, a 620pF ceramic capacitor for a silver mica, no change. I can perfectly align the 40M part of the trimmer board so that one also drops from the list. ? Today I fed the input of the driver with a signal generator at 7.1 MHz. 20 dBm input gives me 100W output and exactly the same behaviour as described above. So there must be something wrong in the driver of pa unit but only at 40M. I’m really out of options now. This is a video of the 101ZD outputmeter which demonstrates the effect: Video of the output at the RF JACK on a SA and the slow rising output on a watt meter with 50 Ohms dummy. Who has an idea what's wrong here. Any help will be appreciated. 73's Erwin, PA3DAF? ? (I posted this problem in several other forums but forgot his one)
A. John Hecht All Messages By This Member #535 开云体育 I have had low drive issues on 40 and 80 related to worn contacts on one of the wafers of the band switch (FT101ZD first edition). ?? toggle quoted message Show quoted text On Nov 5, 2024, at 1:19?PM, PA3DAF via groups.io <PA3DAF@...> wrote: Hello to you all, ? ? ? Recently I bought a Yaesu FT101ZD MK3. It needed a lot of cleaning and was “deaf” due to a blown J310 in the RF unit but everything works fine now except for a strange slow power increase on 40M. I can tune the transceiver to maximum power but it takes about 10 seconds before the output is at its max. When I release the PTT, wait for a few seconds and go back to transmit I have instant full power BUT when I wait for a minute or longer the output power starts at about 25 Watts and slowly (10 seconds) climbs to full power. This happens only on 40M!! I checked and rechecked everything but can’t find anything wrong: - All (HV) voltages OK, changed all HV caps, no change. - Output from the RF unit is stable. - Output on the “rf-out” jack on the back is stable. - Changed driver and PA tubes from my FT902, no change. - Bandswitch is cleaned and all contacts checked with ohm meter. - T/R relay OK. - Aligned the trimmerboards for 40M, no change. - All bands 100W output, 80-90W on 10m. - No ALC indication on the meter. - Checked for cold solder joints in driver and PA unit. The output at the "RF OUT" jack is nice and steady so I suspected that there is something wrong with the (40M) C trimmer board or with a 40M only component in the PA tank circuit. I checked and changed C107, a 620pF ceramic capacitor for a silver mica, no change. I can perfectly align the 40M part of the trimmer board so that one also drops from the list. ? Today I fed the input of the driver with a signal generator at 7.1 MHz. 20 dBm input gives me 100W output and exactly the same behaviour as described above. So there must be something wrong in the driver of pa unit but only at 40M. I’m really out of options now. This is a video of the 101ZD outputmeter which demonstrates the effect: Video of the output at the RF JACK on a SA and the slow rising output on a watt meter with 50 Ohms dummy. Who has an idea what's wrong here. Any help will be appreciated. 73's Erwin, PA3DAF? ? (I posted this problem in several other forums but forgot his one)

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