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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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PM200-13C VR2 question
I just bought a PM200-13C & was adjusting the output voltage. In a
careless fashion, I turned the one pot I saw without marking it, hoping that the lacquer would break so I could see where the pot was originally set. Unfortunately, the lacquer broke off the pot completely & the output voltage stayed put. I then saw the pot behind it, which adjusts the output quite nicely. Now I want to set the first pot back, but can't figure out what its function is. I figured it might be the overvoltage protection, but the ps trips out at 19.2V regardless of pot setting. Over current maybe? Any ideas? Datasheet for ps is he http://www.mpja.com/download/17103ps.pdf I know I was being careless, please don't grill me, I'm just looking for a little help. Thanks, Steve |
#2
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PM200-13C VR2 question
On Tue, 5 Aug 2008 16:58:50 -0700 (PDT), sck0006
put finger to keyboard and composed: I just bought a PM200-13C & was adjusting the output voltage. In a careless fashion, I turned the one pot I saw without marking it, hoping that the lacquer would break so I could see where the pot was originally set. Unfortunately, the lacquer broke off the pot completely & the output voltage stayed put. I then saw the pot behind it, which adjusts the output quite nicely. Now I want to set the first pot back, but can't figure out what its function is. I figured it might be the overvoltage protection, but the ps trips out at 19.2V regardless of pot setting. Over current maybe? Any ideas? Datasheet for ps is he http://www.mpja.com/download/17103ps.pdf I know I was being careless, please don't grill me, I'm just looking for a little help. Thanks, Steve Other than overcurrent, perhaps the PSU can sense an AC Power Fail condition, eg a brown out. Years ago I worked on minicomputer grade switchmode PSUs that had adjustable AC power fail detection. I notice that connector P3 has a "PFD" pin (PFD = Power Fail Detection). I'd monitor that pin while tweaking the pot. See http://www.rsg-electronic.de/de/prod...les/pfc200.pdf Otherwise I'd do some quick circuit tracing. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#3
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PM200-13C VR2 question
On Aug 7, 5:16 pm, Franc Zabkar wrote:
On Tue, 5 Aug 2008 16:58:50 -0700 (PDT), sck0006 put finger to keyboard and composed: I just bought a PM200-13C & was adjusting the output voltage. In a careless fashion, I turned the one pot I saw without marking it, hoping that the lacquer would break so I could see where the pot was originally set. Unfortunately, the lacquer broke off the pot completely & the output voltage stayed put. I then saw the pot behind it, which adjusts the output quite nicely. Now I want to set the first pot back, but can't figure out what its function is. I figured it might be the overvoltage protection, but the ps trips out at 19.2V regardless of pot setting. Over current maybe? Any ideas? Datasheet for ps is he http://www.mpja.com/download/17103ps.pdf I know I was being careless, please don't grill me, I'm just looking for a little help. Thanks, Steve Other than overcurrent, perhaps the PSU can sense an AC Power Fail condition, eg a brown out. Years ago I worked on minicomputer grade switchmode PSUs that had adjustable AC power fail detection. I notice that connector P3 has a "PFD" pin (PFD = Power Fail Detection). I'd monitor that pin while tweaking the pot. Seehttp://www.rsg-electronic.de/de/produkte/files/pfc200.pdf Otherwise I'd do some quick circuit tracing. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Good idea, I wouldn't have even thought of that. That'll also be easier than figuring out if it is for overcurrent, it's rated at 15v ~13A, I don't have any variable load in that range, probably just use a fet & op amp. If I get back to it soon I'll post my findings. Steve |
#4
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PM200-13C VR2 question
On Aug 7, 5:54 pm, sck0006 wrote:
On Aug 7, 5:16 pm, Franc Zabkar wrote: On Tue, 5 Aug 2008 16:58:50 -0700 (PDT), sck0006 put finger to keyboard and composed: I just bought a PM200-13C & was adjusting the output voltage. In a careless fashion, I turned the one pot I saw without marking it, hoping that the lacquer would break so I could see where the pot was originally set. Unfortunately, the lacquer broke off the pot completely & the output voltage stayed put. I then saw the pot behind it, which adjusts the output quite nicely. Now I want to set the first pot back, but can't figure out what its function is. I figured it might be the overvoltage protection, but the ps trips out at 19.2V regardless of pot setting. Over current maybe? Any ideas? Datasheet for ps is he http://www.mpja.com/download/17103ps.pdf I know I was being careless, please don't grill me, I'm just looking for a little help. Thanks, Steve Other than overcurrent, perhaps the PSU can sense an AC Power Fail condition, eg a brown out. Years ago I worked on minicomputer grade switchmode PSUs that had adjustable AC power fail detection. I notice that connector P3 has a "PFD" pin (PFD = Power Fail Detection). I'd monitor that pin while tweaking the pot. Seehttp://www.rsg-electronic.de/de/produkte/files/pfc200.pdf Otherwise I'd do some quick circuit tracing. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. Good idea, I wouldn't have even thought of that. That'll also be easier than figuring out if it is for overcurrent, it's rated at 15v ~13A, I don't have any variable load in that range, probably just use a fet & op amp. If I get back to it soon I'll post my findings. Steve You were right, it adjusts the level at which the PFD pin goes low. Thanks for the help, I would've been hunting for ages. Thanks, Steve |
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