[Techman]

I've got quite a bit of catching up to do with this thread and it's a bit late to do it now, but just to say that I remembered after I'd made my last post on the Tristar and the 2SC1969 transistor, that I'd seen that link to Knights and that I was surprised that they had what seems to be the original transistor in stock and at an acceptable price. However, the transistor with the 'label' stuck on was very cheap in comparison and has proved to work extremely well.

I hadn't used the Tristar for a couple of weeks, so got it out from where it had been stored in a cold room and connected it up and as soon as I switched it on a 'whistle' on USB confirmed instant transmission on this mode - something that it wouldn't have done before the transistor was replaced, certainly not from cold. I've been thinking of various reasons why a solid FM carrier rather than SSB would provoke a failing transistor junction into life, but I'm really only guessing.

You need to keep good care of that Tristar box - it may be the only one left in existence! I've done similar things with original boxes for various things and I've recently found a couple of boxes for items that I still have, but have used the boxes for storing odd components or other items.

I've now fitted a crude and dirty power reducer in the Tristar. I had thought about making it very simple and just reduce the basic power to the RF output stage which would affect all modes, but in the end decided to just have it operational on FM only, leaving AM and SSB as they are. It's that FM carrier that's the killer on these sets and may even be what has helped to finish off that output transistor, even though it did eventually fail on SSB. I've reduced the FM output from almost 25 watts to around 6 watts, although I decided to 're-purpose' one of the front panel switches to switch the 'mod' out if necessary for the odd quick emergency power boost for any 'difficult' conditions.

The second pair of transistors arrived the other day and although I resisted the temptation to try to pick the label off the one I fitted in the radio, I may try it on one of the others now I've got several to play with.

Recent new transistors shown below - packet not opened yet, also innards of Tristar:-