[colorfixer]

Thanks to jhalphen's time to scan the manual, I was able to repair the multiple faults that the set developed from three components. My results are posted here for all to enjoy.

Disassembly is somewhat challenging: You need to remove the three slide switch knobs (carefully) first. Next, remove the three front knobs, followed by all the screws accessible on the cabinet. To remove the radio board from the rest of the unit, remove the metal tab wrapped around the wires running across the top front to the tv tuning pot. Gently remove the black backdrop under the radio tuning scale, then the blue screw located beneath. There are two more blue screws: one accessible from the bottom of the unit, one on the top directly in the middle front of the unit. Gently slide the whole assembly back and tilt it to the right out of the way. It will be connected to the main board with a 4 pin molex connector which carries audio, antenna, and power to the radio. By carefully removing the tuning drum's small phillips head screw (it is locktited on), the board can be carefully removed without having to destring the tuner (not a task for the faint of heart).

The first was the inability to tune the tv on either UHF or VHF. Looking at the VT terminal on the tuner, I found that the tuning voltage varied from 0.2 to 0.5V. Tracing back, I found C503 had totally leaked, corroding the traces under the capacitor completely away. Tracing the lines back revealed that they were corroded under a connector they ran through as well, necessating removal and cleaning of the board underneath as well. Replacing the cap allowed me to move on.

Now I had tuning voltages that were closer to what I expected, I still found that the range while nearly right, wouldn't tune across the VHF band properly. The 30V supply is derrived from the flyback, and C401 had high ESR. Replacing this solved this as well as ripple on the supply that causes the vertical hold to lock out of phase.

The radio board however really made me scratch my head. The AM tuner was completely dead. I quickly determined that the LO on the AM tuner was not running. All the components relating to the AM converter checked out and the DC voltages were nearly spot on, so I was beginning to fear a bad IF coil. When I ran my moist fingers across the board near the converter transistor, I suddenly heard noise. Checking the LO while holding my finger in the right point revealed the oscillator running. After some more prodding, I discovered R823 while the right value according to the schematic, did not provide enough bias voltage for the circuit to start. Reducing this value with a substitution box revealed that the original value was almost twice what was needed to allow the oscillator to start. Replacing this with 220k made it start 100% of the time.