sorenb Posted November 20, 2022 Report Share Posted November 20, 2022 11 minutes ago, Pars said: OK, finally getting around to testing the GRHVs I'm building for the Carbon. Using Soren's post on pre-testing, I had some variances. I marked up the schematic from James above. For the first test, using ~17Vdc thru an ammeter, I'm getting 0.5mA (not 2mA) (points A1-B1) For the second test, I'm getting ~1.3-1.4mA (points A2-B2), which matches Soren's figures. For the third test, I'm getting 10.5-10.9mA (points A3-B3). This may be referring to a Megatron HV900 PSU in Soren's notes below, and I'm not sure I'm looking at the correct points anyhow. I have a 100K resistor paralleling the two 390Ks. Bringing the positive supply up on a variac until it regulates, it seems to be regulating at 55Vdc, which is about what I calculated. Boards are 1.8 version, single fat sw variants. The voltage appeared to be stable; raising the variac a bit didn't change the output. Just checking because the first CCS test was considerably lower than what Soren saw. I did unsolder one end of the 100K resistor and rechecked, but no change. Any thoughts, or just go for full voltage? "you should get ~2mA" probably a typo, ~1mA is what I usually get, depending on the DN2540 ...0.5mA might be just fine Quote Link to comment Share on other sites More sharing options...
Kerry Posted November 20, 2022 Report Share Posted November 20, 2022 For the first test .5 mA is good for points A1 - B1. The third test seems off to me. I’m not sure if A3 - B3 makes sense. The current through R10 is very small. How are you measuring that? Quote Link to comment Share on other sites More sharing options...
Pars Posted November 20, 2022 Author Report Share Posted November 20, 2022 (edited) Yeah, when Soren said to measure the current limiter, I was just injecting a + voltage at point A3 with the negative lead at B3. Ammeter in series with the power supply. I know the 5.1R is the current limiter. Maybe I should inject the voltage at A3-B3 and measure the voltage drop across R11 instead? I'll probably remove the parallel 100K and test at full voltage. Since it was regulating at 55V, it should be fine? Seems like everything is working correctly. Edited November 20, 2022 by Pars Quote Link to comment Share on other sites More sharing options...
Kerry Posted November 20, 2022 Report Share Posted November 20, 2022 If it was regulating at 55v, you should be fine at full voltage. Good luck and let us know how it goes. Quote Link to comment Share on other sites More sharing options...
Pars Posted November 20, 2022 Author Report Share Posted November 20, 2022 OK, powered up and works great. 406Vdc, stable. Bias is 576-580 at bias TP (drifting up a bit). What is the max for pro bias? 3 Quote Link to comment Share on other sites More sharing options...
Pars Posted November 27, 2022 Author Report Share Posted November 27, 2022 Tested the negative GRHV today, same performance. Was regulating at -55Vdc with the 100K resistor in. Removed it and tested at full voltage. -406.5Vdc, stable. Now for the Carbon boards. 3 Quote Link to comment Share on other sites More sharing options...
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