Bumping this one out of a long slumber:
I second the bolded. At the moment there's a TS-820S/R-820 pair in the main station lineup, with another awaiting minor servicing/realignment. Those rigs have been in operation on and off with me since the mid 80s and just keep working. DeOxIt in the potentiometers, on the switch contacts and main harness SIP connectors (every one of them!) does wonders in keeping one of these in good shape.Originally Posted by mw0uzo
A mistake was almost made. My two '980s - each of which showed several operational faults - came close to going out the door last year as "parts/not working". Rig #1 wouldn't switch modes or bands correctly. This was caused by a bad IC on the CPU Board; it's one of three socketed chips. Easy fix, one the design was understood. Rig #2 wouldn't tune with the VFO knob until it had thoroughly warmed up, although the "5 KHz Up/Down" buttons would tune it. Another CPU fault, this possibly involving a timing circuit in the area of the CPU Board which controls the tuning functions. I swapped CPUs with a spare to get the rig working but will revisit the faulty CPU (and it's potentially bad tantalum capacitors) at some future date.Yaesu FT-980 - Excellent rigs, most just need realignment. Can suffer from PSU death which kills PA. Repairable though.
Another fault with Rig #2 centered on the VFO Board. There's a single 30MHz crystal oscillator which generates the master reference frequency; derivatives of this are used by the rig at several points. If it isn't stable or on the correct frequency, proper alignment will be difficult - if not impossible. Yaesu published a couple of Bulletins over the years which cited performance improvements to this circuit, but what was wrong with mine was that its crystal had drifted to the point that proper netting was impossible.
Yaesu to the rescue - specifically, Jose in their Parts Department. (If you ever see him at an event, buy him a beer for me on the Island's tab.) He sourced 5 crystals from Japan, and while they were in transit I managed to acquire a surplus VFO Board for the radio. While all this was transpiring I got hold of yet another FT-980 with cosmetic damage and managed to get it working electrically. Finally finished up Rig #2's electrical issues yesterday and with the new VFO Board installed it can be netted to zero-beat WWV at every spot in the HF spectrum.
Where was I...power supply issues? Improper cooling?
Given the successes in bringing these rigs back to life I've decided to keep them around. I'm in process of designing an external fan assembly and power interlock; when done I'll document all needed materials and provide drawings for the various bits of metal needed to attach the fans to the rig. This modification is completely reversible and makes use of existing fastener locations; no cutting, drilling or filing required.
The best procedure is to remove the supplies from the rigs and remote them but given that bench space can be a premium, this is a workable compromise.
There's even a spot on the new connector bulkhead plate to route a wideband IF Out (suitable for use with a panadapter equipped station scope like the YO-901). That's yet another mod to make the radio more usable.
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