March 5, 20206 yr On 10/21/2019 at 6:40 PM, Kerry said: Yes, R13 sets the current for the reference. I use 4.7K and it was giving me .92mA. Here's a shot of the positive rail... (Wow - It's been sitting out for a couple of weeks and got very dusty) On GRHV regulator board – is there a capacitor C2 between source Q3 and emitter Q4? If so - reason?
March 6, 20206 yr I added this cap just in case. It was more for testing. I was trying to improve the ability to withstand near shorts. In the end I added the external current limiters.
March 8, 20206 yr Author Made good progress this weekend testing the PSU main board and the GRHVxxx. Everything tested works as designed. The LED has a cool feature - it blinks at power on till the timed delay kicks in then the B+/B- are turned on and the LED stays on constantly. Photoed is my test setup powering my electrostatic CFA. GRHVxxx set up for 339VDC rails intended for my SRX Plus. The current draw with the CFA is quite low and over the 4+ hours, the regulated voltages were rock stable and temperature rise was minimal. I hand-soldered everything including all SMD parts Waiting to hear back on the quote for assembled GRHVxxx board. Should have more to share this coming week. Edited March 9, 20206 yr by mwl168
March 9, 20206 yr Very nice!!! I'm all for a batch of non-assembled boards (I actually enjoy SMD soldering), but happy to go with pre-assembled also.
March 10, 20206 yr Author Got quotes back from the fab house (PCBnet). All dollar amounts are USD. All boards are green, 2mm thickness. mini T2 board: $24/pair with 3oz copper (52 pairs) PSU main board: $10 with 3oz copper (72 pcs) GRLV78: $5 with 2 oz copper (92 pcs) GRLV79: $5 with 2 oz copper (92 pcs) GRHVxxx (bare PCB): $4 with 2 oz copper (150 pcs) GRHVxxx (partially assembled): $55 with 2 oz copper (150 pcs) Note that the quotes are based on quantities. The cost goes up if the quantity goes down. A few details about for the GRHVxxx partially assembled boards: 1. The following parts are not populated: C2M1000170D (Q3) - through-hole part to be mounted on heatsink R7, R8, R9, R10 - resistors to set up regulated voltage C2 - do not populate 2. Parts cost with the Mouser BOM I put together is roughly $28 without the parts listed above. The complete BOM is about $36. Tax/shipping excluded. Basically, you are paying extra $23 per board to have it pre-assembled. 3. There is a potential wait for IXCY10M90S parts (2 needed). I think we should opt to have this part un-populated if there is a long wait. There are two IXCY10M90S on each board and they are easy to solder. This will also bring the assembled PCB cost down by about $5. What we do next to move this GB forward: All GB participants please give it some thoughts if you like to go with bare or partially assemble GRHVxxx boards and post your decision on this thread ASAP so I can update the table and get final quotes. If you decide to go with bare GRHVxxx boards, you may consider getting extras just in case. I would assume you opt for assembled GRHVxxx boards for those that do not respond. Edited March 10, 20206 yr by mwl168
March 10, 20206 yr I would like bare PCBs too. May I double the ordered numbers except the T2 boards? Thanks!
March 10, 20206 yr Bare boards please. Also, add the following to my order: +1 GRLV78 +1 GRLV79 +2 GRHVxxx Thanks!
March 10, 20206 yr I prefer assembled, but how much does the cost go up if most people opt for bare boards?
March 10, 20206 yr Author 46 minutes ago, gepardcv said: I prefer assembled, but how much does the cost go up if most people opt for bare boards? I already requested for quote of 50 partially assembled GRHVxxx boards. This new quote should give us a sense of what to expect.
March 10, 20206 yr Due to a lot of things happening these past months I will have to opt out of this group buy. Doing a build isn't feasible for me currently (and most likely won't be for some time). Still big credit to MWL168 for arranging it.
March 10, 20206 yr Thanks MWL OK, I opt for partially assembled but I cut my order. GRHVxxx 2eas GRLV78xxx 1eas GRLV79xxx 1eas Main Board 1eas
March 10, 20206 yr I think I would opt for the partly assembled boards, with or without the hard to get components. If bare would be all there is I would take those too.
March 11, 20206 yr I wonder what’d be the next price break for the mini T2? I have a couple of friends who are also interested in the boards, so they might buy some sets along with me. Also, does the GRLV work as a direct plug in for the LM78xx/LM79xx? I’m thinking of using them to upgrade with stock PSU.
March 11, 20206 yr Author I received updated quotes from the fab house. These quotes are for partially assembled GRHVxxx without the following parts: C2M1000170D (through-hole part to be mounted on heatsink) IXCY10M90S (potential wait due to lead time) R7, R8, R9, R10 (resistors that set up regulated voltage) C2 (Do not populate) 150 pcs - $49/pcs 60 pcs - $60/pcs 11 hours ago, thuytn said: I wonder what’d be the next price break for the mini T2? I have a couple of friends who are also interested in the boards, so they might buy some sets along with me. Also, does the GRLV work as a direct plug in for the LM78xx/LM79xx? I’m thinking of using them to upgrade with stock PSU. The GRLV boards can work as direct plugin for the 78xx/79xx parts. Given the number the GB is at currently, I doubt it a few more sets of mini T2 boards is going to make significant difference in cost. Won't know for sure until I provide the actual quantity for the fab house.
March 11, 20206 yr Please sign me up for: 2x mini T2 board 2x PSU main board 2x GRLV78 2x GRLV79 4x GRHVxxx (bare PCB) 2x GRHVxxx (partially assembled)
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