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fluke PM2813 problem - please help me

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eevblogfan:
hey

so as some of you know I've purchased the PM2813 , great PS in all means , but ther's some problem with it , the sensing is bad , let me explain

so I've got some binding posts for the 3 channels plus the sensing ports , I've drilled the front panel and all fit nicely , so I turned the PS on and connected one of the Channels to my DC load , set to 20V 3A , draw 2.99 ( 3A will turn the PS into the CC mode ) , and obviously ther's dropp of the wires , so obviously you connect the sensing leads right ?  I did so , but the voltage wasn't 20V . without the Sensing it was say 19.7V and with the sensing it was 19.8V , so what's wrong ? well ther's shorting bars on the rear connectors between the + and S+ and the - and S- , so I've disconnected them , and turned the PS on , BUT there was written " CH1 FAIL " , WTF ? 

well I thought there is no internal 100ohm resistors between the sensing and output , so I put some , but the "FAIL" is still there ( Yes I have restarted the PS )

so please , can someone can spot me the problem  ?

thank you in advance ! :)

eevblogfan:
someone ?  :scared:

dr_p:
is it set to local sense?

eevblogfan:
hey

firstly _ thank you :P

so if it does set to loacl . how shall I set it to remote ?

if you mean the jumpers inside , I have already turn them to the "on" position :(

PA4TIM:
I have a P2811, the same psu but only one channel ( firmware seems to be equal)

Did you do the calibration ? Mine was not accurate before I did that. ( Voltage was off and -40 mA without sourcing current after following the manual, ( the resistor thing) then I did what looked more logical to me and used my Keithley 2000 to measure current and now it is spot on)

On my 2811 the 4 terminals on the back are connected to 4 bannana busses on the front ( original option in a sub chassis under the psu, I added a powerswitch there
)
There is a switch beside the bannanas that lets me choose between sense and no sense. It just couples the sense to source lines. There are no resistors. It gives an error if I set the switch wrong. ( and sense is not connected) looks like that is your problem. If I understand right you modified it from back connectors only to front connectors ?)

The sense is part of the feedback. It measures the voltage and regulates the output according. I know because that was the problem on mine. Without the sense it sees no output.

If I remember well during repair: If you put an external voltage on the sense lines you get that as a reading on the display. So the display seems to shows the real output and not the set output ( and that is a safe idea) So that could imply you should see a lower reading using sense and long wires. However I would expect it to regulate voltage again to setting by itself. But I have never checked that. Never used the sense. If you see the set value minus the voltdrop there could be a problem in the feedback. Is the output correct using a multimeter ?

I can try some tests on mine if you want.
http://www.pa4tim.nl/?p=3584 my PM2811, so you can see the switch

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