I had a 19" arcade game color CRT that was very dim... since they are not rare, I decided to experiment with rejuvenating the cathodes. Applying a high positive voltage to the grids (through a current

I did find one with an SPST switch in stock at Digikey for $9.64 plus shipping. Somewhat surprisingly to me, they have 757 in stock. Mouser is out of stock and quoting 23 weeks lead time! Since my sco

I need a 311-340 pot (50 ohm with DPST switch) to fix the graticule lights on my 564. It's open, and won't come apart ("hot-molded" case). 25-30 years ago I would call Deane Kidd. RIP. I'll message Pa

And here you are AGAIN. Don't like it, don't read it. How is your last post not spamming the list? LOL

And yet, here you are posting again. Why don't you stop responding and reading, if it's irrelevant to you? I did, after all, use a 564 and a 7403 to make the measurements :) Some of us are actually in

"No, because a dimmer would work there either way round" I'm sorry... No, what? I wasn't actually suggesting using a light dimmer, just illustrating a soft start ;) Also it would take a hefty one due

Yes, I understood that, thanks... but the 240 volt, 20 amp outlet (protected by a standard SquareD "QO" breaker) can handle the AC inrush adequately, especially since I have an NTC inrush limiter on t

Interesting suggestion, thanks! I could use a triac with a slow ramp-up of duty cycle, like turning up a light dimmer? Seems like it would not lower the peak inrush current at the diode though, just c

Found a data sheet online for the bridge: https://datasheetspdf.com/pdf-file/1391462/GoldElectric/MDQ200A1600V/1 Assuming those specs are accurate (not always the case with Chinese parts!), it looks l

Some transient measurements with my balky old 564 storage scope - just added to an album. The first peak (measured at the transformer secondary = bridge rectifier input) as the capacitor charges is 56

Thanks for the observations, Ed. In reverse order: I actually checked the magnetizing current when I first got the transformer, and it doesn't even move the needle on my Amprobe clamp-on meter's 6 amp

All I was interested in was the magnitude of the initial peak current in the first quarter-cycle (4 ms). The thermistor resistance initially is known to be 2 ohms. Although they do heat rapidly, it's

The mil-surplus equipment I'm interested in powering has dynamotors. As you know a DC motor is nearly a short circuit when stationary, and very few if any dynamotors had a soft-start circuit. They are

I'm getting lost... which CT are you referring to? I measured the AC inrush current directly across the 2 ohm thermistor, using the scope. That was more for academic interest since it doesn't pop the

I forgot that I already have a great measurement device, very recently acquired! <slaps self on head> Namely, a Danfysik "Ultrastab" 867-700I current transducer. DC to 100 KHz bandwidth, maximum curre

I built a 28v unregulated power supply to run mil-surplus equipment that's capable of 150 amps DC. Basically a 5 KVA toroid transformer (240 volt primaries), a 200 amp bridge (big heatsink and fan-coo

I've been rewiring old houses since the late 70's (not professionally, but for personal use) and have always used Square D "QO" series. They are a bit more expensive than the usual "homeowner grade" s

Stancor P-8191 or Thordarson 26F65 is a 6.3V primary, 6.3V secondary, 1.2 amp, with 5kv isolation. No idea where you could find one, though...

I've only had one Rifabomb ever, but it was spectacular... last year, a DEC VT240 terminal that had been in non-climate-controlled storage for a long time. I powered it up, and it was working other th

I must be missing something. If you have some S1's known to be working (in your 7S11) then they should work in your 3S2 also, so any problems other than calibration will be in the 3S2... Hopefully you