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/diy/ - Do-It-Yourself


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>> No.2042066 [View]
File: 32 KB, 870x298, bingus.png [View same] [iqdb] [saucenao] [google] [report]

>t.recovering OP
Have any images for me?
t. 85% active OP

It might not be the only issue, it's popping pretty quick to be just a 1/4W issue. Though maybe it will subside as just being due to inrush current to the capacitor. Pretty sure you can take the cap out and it will still work, but it might flicker, maybe even make noise.

Looks like it's the vacuum tube equivalent of a zener diode, which is interesting. It has a drop of about 75V, though it needs at least 105V to strike. Assuming 170VDC after the cap, that's about 95V across the 2k resistor. The resistor will be running somewhat hot at 4.5W, and the current through it will be 47mA. Then 170V across 47kΩ is an additional 3.6mA. So about 51mA going through the 100Ω resistor is 0.26W, which is barely past the limit of a 1/4W resistor.

So it should definitely work without the capacitor (average current will drop), and doing so will eliminate the inrush current, but doing it prolongedly may reduce the life of the tube, so I'd aim to replace it with a 1W 100Ω in the near future. If you want, you could integrate the input energy minus the thermal radiating energy to see how many watts you need, but that sounds like a pain. If 1W was good for them, it will be good for you.
You could also consider using a capacitive dropper circuit to remove the hot resistors, but I'm not sure what the time/voltage profile of the tube will do to the capacitor current.

Pic for reference.

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