Started working on old radios again when i got this yaesu from ebay the frist was to replace the old capacitors in the power supply checked for shorts replaced the 6146 tubes checked resistors in power supply and checkes resistors on the tubes . Worked great frist qso was costa rica 10 meters had it for about a month when smoke came out of the radio a flash over inside one of the 6146b tubes from screen grid to control grid took out a screen resistor and some resistors in the alc ckt . Replaced those parts . Worke fine for about a month .what happened was when in receive mode it worked ok but when i would turn the filments on the 6146 tubes after a short warmup it would blow a fuse in the primary's power transformer . Well i found that the grid had no negitive bias a diode in the power supply opened up in the bias ckt . Replaced part and tubes been working for about a year now .great radio it is my back up radio now bought a yasue 891 .If you dont know how to work on old tube ckts i woul not recommend this radio but if you do its a lot of fun but can be challenging at times great receive but the ssb can be tricky.73
I bought this rig as a project rig in junk condition in 1991. It had fallen into the hands of a hacker who had converted it to 11m and damaged parts all through the rig...cracked slugs, damaged PC boards, etc. Cosmetically it was good, so I bought as service manual and set out to bring it back to life. After a couple of months of work in my spare time, it was back on the air.
I was very impressed with the receive audio quality, rx sensitivity for it's day, stability after a short warm-up, and just the overall handling and feel of this rig. It was Yaesu's contest rig of the late 70's, and had features like: Adjustable Audio Passband Tuning, built-in keyer, VOX, Auto Mic Gain Control, adjustable notch filter, adjustable I.F. width, tx processor, etc.
It still has a prominent location in my primary operating position, and is used nearly every day.