Video Circuits V15 – Tripler Tester
This is a piece of test equipment I’ve been looking for, for a very long time. I had thought the chances were next to nil, to ever encounter one. I’ve not seen another in all the years I’ve been looking, and I only found one reference in a Television magazine from the 70s.
Normally I wouldn’t touch anything coming out of the ‘Video Circuits’ stable, especially not their CRT tester/rejuvenator. However, the Tripler tester is something that has intrigued me and as far as I know, unlike CRT testers, nobody else had ventured into providing an instrument to test triplers.
The V15, if you’ve not already worked out from the thread title, is an EHT tripler tester. It tests drive absorption and final output on load. It produces pulses of around 800V pk-pk at 625-line frequency. There are five buttons, mains, 1-3 for DUT and the test button. Efficiency results are displayed on a meter, as a percentage. In fact, it tests not only triplers, but doublers and quadrupler’s too, though I only know of one set that used a quadrupler.
- Single/Doubler
- Tripler
- Quadrupler
I doubt many, if any, of these have survived, there’s certainly nothing online. Thus, as far as I’m aware, this is an exclusive to VRAT. I will document as usual, with lots of photos, and put through its paces. The first thing to note is just how tiny it is. From the only photo I had from the TV mag, I assumed it was a large piece of kit. In fact, it only measures 8″ wide x 3.5″ at its uppermost height and 3.5″ deep. Inside, there’s not a lot to report, a TX, a switch bank, a couple of diodes, two electros, a few caps, resistors, pot to the meter and a single Brimar 12AU7 (ECC82).
Anyway, here is a short video of the device.
A good friend supplied me a faulty ITT FT110 tripler, so I could see if the V15 tripler tester detects the fault. As you can see by this next photo, the V15’s absorption test did reveal the FT110 tripler is only at 60% efficient, and would explain why the TV it came from was having problems. The tripler would work ok until there was any peak white in the picture leading to the lines and a screeching/arcing noise.
It was suspected that the tripler might actually be OK, it could be the resistor inside the anode cap failing. To see if this was indeed the cause of the fault, the anode cap was removed along with the resistor. As can be seen in the next photo, repeating the absorption test on the tripler now shows it to be OK showing 100% efficiency.
