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Pars

High Rollers
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Everything posted by Pars

  1. 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.
  2. Happy Birthday! I hope you have a great one Bryan!
  3. Just a quick and stupid question: when testing amps/psus not in a chassis, do you tie any heatsinks to safety ground just in case? Just thinking that might be a good idea, particularly on HV stuff.
  4. 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?
  5. 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.
  6. 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?
  7. Toto, I don't think we're in Florida anymore...
  8. ChipOneStop shows some stock, not sure how trusted they are. https://octopart.com/dn2540n5-g-microchip-47153345?r=sp
  9. Happy Birthday Chris! Don't catch too many fish...
  10. Happy Birthday Mikey!
  11. I usually solder at around 700F (or up to 750), which is higher than your temp. Where did the boards come from? I haven't had problems with lifted pads in a long long time.
  12. There are BOMs in the thread, but I've attached one here. There are alternate parts for some items, so check it over before you place an order. You can oftentimes save money by buying in quantity, particularly the SMD resistors (100 isn't unreasonable). The pricing in this isn't accurate as well. Read thru the thread regarding cases (or search). ssdynalo-v1-4.xlsx
  13. RIP Ray Guy, Oakland/LA Raiders punter. Loved watching him when I was a Raiders fan back in the '70s/'80s https://www.cbssports.com/nfl/news/ray-guy-dies-at-72-raiders-legend-first-punter-inducted-into-pro-football-hall-of-fame-passes-away/
  14. Started watching The Peripheral. Pretty good; only watched the first episode but will try to catch some more this weekend.
  15. Happy Birthday Dusty! Hope you have a great one!
  16. Seems like it should work with the star ground. In your drawing, you only show a single secondary from your transformers. These should be dual secondaries (or center-tapped, depending on the GRLV version). You are getting the proper +/- dc voltages from your GRLVs? You would be seeing a ton of dc offset if this were the case, just asking.
  17. In general, we prefer to avoid spoon feeding newer members and encourage them to do their own research. At some point, Kevin added a 3rd bridge and the capability to use a single bridge with a CT transformer (like amb's sigma22). Obviously you don't use all 3 bridges at once. If you look at the popular post feature on the right side, above, you'll see some of the key posts in this thread. I'm not sure, but jamesmking may have done a version history of the GRLV at some point. I know he did for the GRHV. His July 27, 2021 post shown in the Popular Posts might be a good one to look at. Using the search bar and searching "largecap" will find some info, including a recommendation for what board version to use...
  18. Happy Birthday Wayne!
  19. Happy Birthday Jim! Have some fun!
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