Yaesu FT-101 Repair Adventure

Well it has been quite a while since I last worked on the FT-101s. I've done quite a few projects in the meantime including repairing Hallicrafters, Collins, and National receivers.  I have gained some more and better equipment also. Anyway I still had this FT101 sitting under the workbench, so I finally cleaned the bench off and put this baby on it.  Initial tests weren't too good.  But it turned out that I just needed to Deoxit the volume pot and RF gain pot again.  I also put some on the band switch.  After that, the internal calibrators seemed to be working correctly and I was getting internal signals. So I hooked it up to my Service monitor and gave it a signal.  I'm happy to report that it could hear .5uV signals on 15, 20, 40, 80, and 160 meters.  I didn't play around with 10 meters too much because I don't remember what frequency crystals are in it. So far it is looking pretty good.  I did check the clarifier, and it is off fr...

I put the second FT-101 E on the bench.  I put a hot set of tubes 2375/1200 in it, and neutralized the finals.  I let it warm up and measured the power output on all bands.  160 was low at 25 watts, but 80-15 meters was a good 100 watts.  I was able to get 100 watts on 11 and on the bottom of 10 meters.  On 29 Mhz, the power dropped down to 45 watts. I'll call that a success. Now I just have to align the transmit and receive frequencies and do some on the air testing.

I worked more on the FT-101 E today.  I installed a good set of tubes.  Actually they are a really hot set, reading 2400/1200 on the tube tester.  I neutralized them with the cold neutralization procedure. I got good output on 80, 40, 20, and 15 Meters.  The output on 10 meters was below 10 watts. This leads me to believe that something in the 10 meter tuning section needs to be adjusted. I will try putting a good set of tubes in the second FT-101 E and see if it does the exact same thing...

I took a break to fix some other equipment so that I could sell it at a swapmeet. I put one of the FT-101E's back on the bench and checked the output.  The tubes are unknown, but seem to put out good output on 80 and 40 meters. I can only get about 9 watts on 10 meters.  I've spoken with some people, and they say soft tubes can cause the dropout on 10 meters. So next step is to swap the tubes out and re-neutralize the new ones.

I finally gathered up all the 6JS6C tubes that I've collected and brought them to a friends house to test them.  Looks like I have 6 pairs of tubes that test good.  Four of those pares test really good, like 2000/1200.  I ended up with about a dozen bad tubes and a dozen good tubes.

I'm working on getting the second FT-101E up and running.  I tried to neutralize the finals, but it wasn't acting correctly.  I removed the red label Silvania tubes and put in a yellow label set.  It seemed to neutralize fine.  I checked the output power on 80 meters and it was 100+ watts.  I reset the bias to 60 mA.  I checked the output on 10 meters and I'm only getting 15 watts.  I swapped out the driver tube, and there was no difference. I will have to put the other 101E on the bench and check its power output on 10 meters. Its either something wrong with the unit, or the tubes.

I'm going to start on the 2nd FT-101E next.