I don't think I'm in the market for uTracer7 but the uTracer6 has the positive grid bias option. That allows testing regular valves at 10V to 28V HT. Some need +1V or more when running off 10V to 15V. Also allows testing / curve tracing of FETs.
The only real use I have heard for old microwave oven transformers is for home made valve transmitters in which kV are needed for supplies.
My home made valve test gear does use lower voltages, similar to those I work with, and has some ability for positive grid voltages as I have switched grid biases built in. It's also easy to couple up an external variable supply and I have a little module for that too.
Tracy
The big snag with microwave oven transformers for powering transmitters etc is appalling voltage regulation.
"The big snag with microwave oven transformers for powering transmitters etc is appalling voltage regulation."
That is addressed in the article by removing the magnetic shunts, probably not as good as "a bought one" but a lot better than the original.
I'm not going to get a uTracer7, but I will examine how easy it is to dismember & rebuild the MOT I have. Certainly seems easy to remove shunts and have a custom airgap.
Now, where can I get neon sign making gear to make my own Geissler tubes.
https://en.wikipedia.org/wiki/Geissler_tube
Surely with all going LED and Screen based, someone should be giving it away?
That is a wonderfully insane tracer! I don't need one and don't want one - but can certainly sit back and admire the machine, and anyone with monster valves that need the specs.
They are used as a cheap way to to power tesla coils too.
I have a stack of MOTs from my "coiling" days - they were used for Jacob's Ladders, traditional RSG (rotary spark gap) Tesla coils and with a replaced secondary, for spot welding.
Many other uses too, but they can also be lethal; 2000V at around 500mA is not great for the heart or skin. Folk use then to create "Lichtenberg figures" aka "Fractal wood burning" by burning the surface of wet wood using a couple of probes connected to a MOT. Every year there are
a number of deaths and serious burns due to the users not taking the correct safety precautions. MOTs can be really really dangerous.
One issue is that one end of the secondary is connected to the laminations, so there's no galvanic isolation and even if you disconnect the ground tag, the insulation between the inner windings and the core is insufficient to handle an isolated 2000V secondary. They're not designed for continuous running either.
Back on topic, I have a prototype original uTracer and an upgraded V3+ one. Had them for many years now. No plans for a V7 as too many projects already.
BTW, I dislike the default Windows app for the uTracer - it's functional but a bit of a horror. Nick Barton has done a FAR better (IMHO) interface for both the uTracer 3 & 6 at
https://bmamps.com/v01/home/techie-corne...cer-utmax/ - I had a chat with him about making it work for the uTracer 7, but he has no intentions of buying a 7 to play with as he says he'll never use it.
I've known Ronald for many years, back to the Nixie days - he's a good guy and very helpful.