PM200-13C VR2 question

[sck0006]

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 here:
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

 

[Franc Zabkar]

On Tue, 5 Aug 2008 16:58:50 -0700 (PDT), sck0006 <skamego@gmail.com>
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 here:
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/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.

 

[sck0006]

On Aug 7, 5:16 pm, Franc Zabkar <fzab...@iinternode.on.net> wrote:

On Tue, 5 Aug 2008 16:58:50 -0700 (PDT), sck0006 <skam...@gmail.com
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 here:
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

 

[sck0006]

On Aug 7, 5:54 pm, sck0006 <skam...@gmail.com> wrote:

On Aug 7, 5:16 pm, Franc Zabkar <fzab...@iinternode.on.net> wrote:



On Tue, 5 Aug 2008 16:58:50 -0700 (PDT), sck0006 <skam...@gmail.com
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 here:
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