Hi Steve,
Thanks for that: it's always interesting to see these brochures from the time. It makes it all more real somehow!
It also answers another question:- why is my LOPT that I have been playing with different to that shown on the VT161 circuit?
The VT161 must have been the old model. Totally hand wired chassis and 90 degree, fat neck tube. The VT163 & 164 pictured have the all new 110 degree tube and are all on two pcb's!
I'd not found those models as they are in a different R&TV book, but my LOPT has the same winding arrangement as those so that's interesting (at least for me!)
Out of interest, is there a date on the leaflet?
The LOPT has finally been put back in the chassis- hopefully for the last time! It is working perfectly!!
Apart from the increase in EHT mentioned above, one other bonus is that it runs cooler than before. Not that it got excessively hot before, but it is now cooler.
So I'm now wondering if the various LOPT's I've got that get way too hot, but seem to work, might also have a similar leakage problem? I've never yet got to the bottom of that problem.
Sam, yes, this former was a paxolin/ SRBP type of material. It was in a bad way when I first removed it and I repaired the burnt hole with Araldite. I guess once the material degrades, it becomes leaky with several KV pulses applied to it.
So far, the repair is working well! and I've now got a very good picture. I'm now turning my attention to the horizontal sync which is not all it could be. It's prone to line tearing and the H hold is critical. The verticals are slightly cogged as well. The problem can be cured by de- tuning slightly so that the picture is lower definition. I suspect that some of the higher frequency video components are getting through the sync separator and disturbing the line timebase- I can see it on the scope as noise on the line pulses.
I can also effect a cure by placing the meter probe on the grid of the separator- the picture goes smeary, but the tearing & cogging stop. More investigation needed!
All the best
Nick