Excellent work
A friend of mine (Vintage Pete) restores radiograms and has a lot of experience with timber finishes over many years.
His advice, basically, is if the surface needs stripping and refinishing, forget about french polish and nitrocellulose and use two-pack epoxy.
Very nice, that brings back some happy memories, what are the books on the floor, mullard data books by any chance?
Powered the C2219H up today, it was fizzing quite merrily, accompanied by a very strong smell of ozone. Upon inspection, nothing could be seen. At first, I thought it might be a dirty anode cap or perhaps arcing from the tripler.
At the time I forgot to test the old tripler, clearing out the workshop bin today I found it so tested it on the V15. It told me what I already knew by substitution, but it does reveal just how bad the old had become, only managing a little less than 30% efficiency. Glad I didn't run it too long, as who knows it might have taken the LOPT with it.
![20231023 145901[1]](https://www.radios-tv.co.uk/wp-content/uploads/wpforo/attachments/884/15761-202310231459011.jpg "20231023 145901[1]")
@crustytv I have never seen a Tripler tester! I had no idea such a thing existed, You live and learn! 😎
@crustytv a very interesting bit of kit that, not sure how it manages to test efficiency though, I would have thought a tripler was either putting out the right voltage or wrong voltage, have you tried a brand new one and seen what result it gives?
a very interesting bit of kit that, not sure how it manages to test efficiency though, I would have thought a tripler was either putting out the right voltage or wrong voltage, have you tried a brand new one and seen what result it gives
Hi Michael,
I can assure you the V15 is not snake oil, it does test and correctly identify a good, poor or failing/failed tripler. 👍
When I first got it, I tried brand new triplers as that's all I had, they showed as 100% efficiency. I thought OK that's all good, but I need a duff one to see what happens then. I didn't have to wait long as John @jayceebee was working on an ITT FT110, the colour was a bit strange and there was a horrible screeching and tearing at high brightness. When he replaced the tripler all this went away.
I asked If I could borrow his failed tripler to see what my V15 tester made of it. The V15's absorption test revealed the FT110 tripler was only 60% efficient, so there was a problem with it. John then stated that it might be the resistor inside the anode cap failing, so I snipped the anode cap off, thus removing the resistor, and did the test again. This time it showed 100% efficiency, clearly the V15 was reading correctly, the tripler was returned to John for stock rather than ending up in the bin. Then we have this GEC's tripler, there was loud fizzing and ozone which also resulted in disturbance on the raster, once replaced with a new one, the problems went. When I tested the old one yesterday, it was only just reading about 28% efficiency.
Of the three tests I've explained in this reply, one tested at 100% for new, one at 60% for a failing anode cap resistor and my GEC the worst, at just 30% efficiency. Clearly, this would indicate that triplers don't have just one failure mode i.e. work or not work, but may soldier on in a less than efficient state before final failure.
Recently, a friend of mine had a tripler fail in a TV, he replaced it with a new one only to have the LOPT fail a few hours later. It was felt that the previous tripler failing likely caused the LOPT some damage. Who knows, had the original tripler been tested, we may have picked up a hint of trouble with regard to efficiency and avoided trouble, then of course we may not. Either way, it's a very useful and rare piece of test equipment, and after many years of searching for one, I'm glad I have it.
I did a thread on this a while ago here, I also did a YouTube video which I believe you commented on. I don't profess to know how it does what it does, only that the results speak for themselves. All I've managed to glean is it tests drive absorption and final output on load. It produces pulses of around 800V pk-pk at 625-line frequency. I'd love to see a circuit, but that's highly unlikely, the only way I suppose is to reverse engineer it.
@crustytv I just had a look at your YouTube link and yes I had commentd and forgotten all about it, it would be interesting to measure the voltage coming out of the tripler and see how it goes back into the unit for measurement, I wonder if this is just measuring voltage??
My monkey brain has always imagined the following:-
What we know is the device produces 800V p-p pulses, which are fed via the drive output to the input of, let's say, a tripler. If said tripler is doing its job, then surely this would mean at the EHT cap we should expect 2.4kV?
To date, all I've ever measured is the unloaded (no tripler attached) drive coming out of the V15, which as I say is the input for the D.U.T. it was 854V.
If all the above is true, when tripler is selected, the voltage at the EHT cap would surely mean you'd get 2.4KV. This fed back into the V15 via the red lead, and again I imagined the associated circuitry is designed to display on the meter how close the actual tripler output voltage is to the expected voltage, thus the efficiency of the tripler represented as a percentage.
With a Quadrupler I'd expect 3.2kV and a doubler 1.6kV.
Suppose I could stick my EHT meter on the cap whilst it's being tested, though I've no idea though if that would skew the test or circuits having it attached.
@crustytv The Battenburg has such a high input resistance I think it'll be okay.
