Is it better to put higher or lower value resistor on R209 and R207 ? I mean which way is safer.
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That's the problem. Them 2 resistors I am not so sure of what there was in there, I went after the carnage trying to identify what was there first place. Some were really easy to identify, others not so. The thing here is to go through example circuits that are similar to yours and see what they used. Pull up some datasheets from the PWM from different manufacturers and compare. Sometime you know the resistor code started with a 1 and ended in a zero for example. So far R207 and R209 I haven't come up with anything too good uet.
R207 ended with xx01. So a 1001 = 1k ohm. Sounds plausible and should work.
R209 got not a clue. Cording to your schematic, it is a gate drive resistor to a different MOSFET. Knowing that it should be something less than 100 Ohm. Don’t forget there are already 22Ohms in line.Last edited by CapLeaker; 05-21-2024, 08:27 PM.Comment
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Oyyy, made a mistake yesterday, R209 goes to the Source, not to the gate. It’s a current sense resistor. So 1 v is the max here. As soon as the CS pin goes above 1V there is current limiting / cut off. Thinking about this, the resistance must be quite high. Higher than 1k Ohms. More like something 10k or 100k Ohms. Can you check the capacitance of C204?Comment
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Heatsinks and fans out here are some more photos.Comment
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What a pain that is! Looks like it has some bad solder joints too.Comment
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The biggest problem with an inverter welder is not continuity like voltage, it's more current based like. The circuit has to be able to carry the current. I do remember a case not too long ago, where one of the problems was burnt track on the PCB that made continuity but couldn't carry any load.
So what was your “incident”? I don't see anything blown up (yet)?Comment
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Show me what heatsink and what diode. The welder may not turn on if the low voltage supply isn’t working.Comment
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So this is the front lcd panel with potentiometers and welding style adjustments with a small pcb it’s connected with 2 cables to the main boardComment
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These are the 2 connectors. So I assume the small board next to it what we were fixing it’s part of the supply.Comment
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These two are bridge rectifier’s am I right ?Comment
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yesComment
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Hello. I have done some measurings. So on the small board the IC UC3843 pin6 (output to gate) is only 0,7mV and it seems like it didn't want to drive the mosfet
How much Volts should i get on mosfet Drain and Source ?
here is a link to ic UC3843BN datasheet(1/15 Pages) STMICROELECTRONICS | HIGH PERFORMANCE CURRENT MODE PWM CONTROLLER (alldatasheet.com)Comment
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Hello everyone
I attach a schematic and teardown photos for the DoCreate DHJ567 handheld spot welder. I bought this welder for temporary use while my supercapacitor welder was waiting for replacement parts. It cost only £24, though there is a screenless version available for £17.
Performance: The absolute maximum it can handle appears to be 0.15mm of pure nickel. Reliability was not great - welds were very inconsistent, ranging from weak attachment to burning through the strip. However, I was able to build a 5S2P pack without losing any cells. It's a bit difficult getting... -
Hello people. I trying to repair my Sencor TV. No standby light, not tuning on what i found there is 6V where 12V should be and 8V where 16V should be. Any suggestion?05-18-2024, 01:40 PM -
This is my own welder, that blew up while welding. There is no warranty on it. Purchased it a year ago, sealed box from Craigslist.
It worked great until now, about a year.
What I have found is a blown trace next to the main capacitors, it seems like also got damaged the SMPS IC, output MOSFET and a 1 Ohm resistor to the ground from the MOSFET.
After replacing these components, the relay, fans turn on and it sounds like it's working, but there is no output voltage for the welder, LEDs do not turn on.
So there are more components that are damaged.
I'm having a hard... -
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HP Modelnumber: 14-dh0061nb
This laptop had a shorted cap on a Vcore section. After replacement is works again. But there is still a battery issue.
The battery is HT03XL and with the built-in component test from HP, in the Power section, I get an error: Logic State: Calibration required (20), Charge state: Blown Fuse (42)
I have another same battery, also with error: Logic State: Very Weak (70), Charge state: Blown Fuse (42)
And a third battery TF03XL (looks identical) with error: Logic State: OK (0), Charge state: Blown Fuse (42)
All these 3 batteries are charging...
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