A ham friend had this system in storage for about 15 years. Said the radio didn't xmit and the tuner was in an unknown state. I offered to take a look at it.
Both units were very dirty. The radio seemed to receive OK, so I took it apart and expected to find blown finals but upon troubleshooting I found that there was no input signal to the final amp board. Turned out that all it was, was a loose connection on the other end of the little coax cable feeding the final stage. The burned out lamps were replaced with LEDs. After a complete cleaning and a full service alignment, it works great now.
The tuner was another issue. The nylon shaft couplers were cracked causing the capacitors to slip, where the hex screws were, and had to be fixed using small stainless steel hose clamps as no suitable replacement couplers could be found. The metering system (FWD power and REF power) did not work, because it was found that the schottky diodes (5) were all defective in the rf detection coupler. I ordered the correct diodes NTE583 (substitute for 1ss101), but for the time being, I tacked in 1N914s and that part of the tuner works OK for now.
However, the automatic tuning feature did not work either, and this was caused by a defective JFET, so that had to be replaced as well.
Also, typical of these older units the lamps were burned out and were retrofitted with LEDs. And the memory backup battery was no good, so tacked in a new battery holder and put in a CR2032. The tuner can work with the radio, as it can track the band switching via a cable, but the original cable was missing, so I ordered the two types of connectors needed to make up one - a 9 pin molex and an 8 pin JST type connector. Now the automatic bandswitching works also.
I think the owner will be happy with the results.
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