High-Voltage Power Supply Module DC-DC ±45-390V Adjustable Step-Up ZVS Capacitor Charge Ultra High Voltage Adjustable Output

I needed to subject high voltage vacuum tubes to gradually increasing DC voltage. It is called "re-forming" tubes and you do it for tubes that have sat on the shelf for a long time. I hooked this DC-DC convertor to a 30V DC source and reformed the tubes at 100VDC, 200VDC, 300VDC and 390VDC for hours each. Never got too hot (I limited the current with a resistor). Worked fine. Caution: there's a fair amount of noise on the output--it isn't hifi quality DC, so you might want to add choke- and/or capacitor-based filtering to smooth out the output. I didn't need that, hence the 5 starts. For the price it is tops.

I have had two fail, both ending with the 12v by-pass cap exploding quite violently (don't lean over the module when it is powered!). With the first setup, I connected the gnd-to-+V output to a battery bank at 197v, via a 10 ohm resistor for checking the current. Before connecting to the battery bank, the module +V voltage was set to 205v. The charge current started at 300 ma. I adjusted the pot to lower the voltage setting, and the charge current decreased as expected. When it was about 1.5v (i.e. 150 ma) all hell broke loose. The 10 ohm resistor turned brilliant yellow. Something on the bottom side of the board lit up. A second of two later the 470u cap across the 12v input exploded. The rectifier diode (US3M) in the +V side got so hot that the solder melted and it fell off. Thinking the battery bank power fed back through the +V circuit after the output diode shorted, I tried a second unit and added a 1N1007 (1000v) diode between the +V and the battery bank. The charging current started at 350 ma, then after a few seconds suddenly stopped. I quickly disconnected the 12v, then disconnected the battery bank. Then reconnected the 12v to check the +V and -V voltages. In a matter a few seconds the 470u cap exploded. (Again quite violently). The diode in the +V output was shorted and had gotten hot enough to melt in a plastic sheet I had placed under the unit (to prevent another burn mark on the bench). I haven't traced the circuit on the module. It is based on the UC3843B IC. A cursory look suggests that it originally had a current sensing resistor that is now by-passed so there is nothing to limit the current when the FET turns on. High peak currents on the 12v line could cause a oscillation with the 12v cable inductance and the 470u cap. (I've seen a similar situation with pwm of a FET for a motor control.) Bottom-line: Safe operation of the module operation appears quite dependent on the load.

Purchased this to power the high voltage backlighting of a broken Samsung TV, easy to adjust, and minimal voltage deviation based on load. Overall works great!

Fast shipping, well built, but are these 4 leads supposed to be soldered? Easy fix if they are.

Large inrush though on start, lots of parasitic drain. If you're using it to pulse something use a big cap on on supply side and 2x relay board to switch the in and the out. Power up 2 sec before you need it, and 2 sec after done power back off. I used it to ring an old desk telephone (90vac 20hz) via an ARM board using 2 GPIO lines to do the above, using the relay itself to PWM the bell. Works fine.

20V ripple on 60V output. What a piece of junk.

Work as expected and expressed. However they're much better than was explained or expected. Once you've put the neccessary extras that's also found here they can be used to support emergency services during a storm with only 6+ volts to operate, or in using a 3v to 12v source they're even much better to use to handle mall electronics and lighting at q10 voltage to higher, then with any of the Ampage boosting units they'll even power much stronger electronics including refrigerator and ac units at the set state of electrical compasity

Worked great for a while and then inexplicably just stopped putting out high voltage just outside the return window.