| Electronics > Repair |
| Xantrex/Sorensen XHR 40-25 schematic? |
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| ifonlyeverything:
You were right about something killing the regulators. I think the -15V regulator is blown (it's outputting roughly -18V instead of -15V) and the 15V regulator is running super hot because something is pulling it down to 8-9V. Auxiliary power supply output is still fine. Will dick around with this later but I'm guessing the OP07 block is screwing me over, since that's where the blown open tantalum capacitor was found. |
| coppercone2:
thermal imager might come in handy here . seek thermal or probing stuff (its fucking annoying though) |
| ifonlyeverything:
--- Quote from: coppercone2 on April 14, 2024, 01:11:07 am ---thermal imager might come in handy here . seek thermal or probing stuff (its fucking annoying though) --- End quote --- Thermal camera didn't reveal anything unexpected. Only thing heating up were the linear regulators and a couple small value resistors on the 6.2V zener and the linear regulator. The zener was regulating fine. I replaced the linear regulators and powered it off my bench supply, didn't pull above like 0.05 amps at idle (due to those small value resistors.) Connected everything back up same problem with U238 being pulled down and U252 instantly shorting out. One of the output capacitors (new Nippon Chemicons from LCSC) blew the fuck up too. :palm: |
| ifonlyeverything:
I'm not sure why it didn't pop up on the thermal camera before but C239 was hitting 50C so I swapped it with a new through-hole ceramic cap. I replaced the output capacitor that blew and replaced the linear regulators with brand name versions because I realized my stock were counterfeits I bought from eBay years ago. I did some light load testing and I believe it is working. Horrible transformer buzzing is gone. Linear regulators U238 and U252 are cool to the touch and are outputting the correct voltages. U257 is running quite hot at 80C case temperature but it's not heatsinked as per design. It feeds the fan and I measured the fan pulling 100 ma, so I guess it's just engineered to run hot. I need to mess around with some of the trimmers because the output voltage is half a volt more than the CV limit, but everything looks stable at a few hundred watts load. Just need to come up with a way to test it at its rated 40V and 25A. In summary: C151 visibly blown; C239 shorting causing U238 and U252 linear regulators to short or blow; U257 linear regulator replaced preventatively; output capacitors C137, C140, C141, C143, and C162 replaced preventatively; new C137 capacitor blew so it was replaced again. |
| coppercone2:
nice I had to take mine apart to wash it the other day because coolant spilled on it because it was bein used as a table for a pump (non conductive but still) are all those caps electrolytic or other types? |
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