Hi everyone,

So, I finally put my hands on my Buffalo IIIse full kit with IVY III and while the single Placid HD PSU was fine, I got some problems with the bipolar one.

First things first, the current and voltage readings :

Transformer is outputting 2x 16.8V (approximately) so this is fine.

After diode bridge, about +/-20VDC (between TP ground and TPin +/-)

Between TPin and TP CCS +/- I get around 0.340V

Between TP ground 2 and Vref +/- I get +/-3.83-3.84V so again everything is still correct according to the manual.

On the other hand, measuring output voltage and current at the output : big problem.

On the positive side : ground2/TP out+ I get around 9.5V and 655mA

On the negative side : -8.58V and a crazy 1.2A !!!

9.57V and -8.22V for the shunt voltage. (between ground 2 and TP V shunt outputs)

Here I must say that I DIDN'T killed the 4x variable resistors, they still adjust fine.

Solders looks clean and I haven't inverted the diodes, leds or BC transistors.


I don't know where is the fault here.


I suspect a bad value of RG/R7 as RF/R12 measure fine (edit : one seems off too and doesn't read 2K ohm but it's difficult to read it without test points)

Why is it sinking so much voltage ? Why does the negative side has so much current ?!

Any help appreciated, thank you very much.

Stéphane.

Edited by user Saturday, May 9, 2015 4:19:21 PM(UTC)  | Reason: Not specified

Hello avr300,

The picture you posted is the V2.1 and mine is V1.0.

I can dial current and voltage with VR1 and VR2, yes, but not by a big range.

Since it it should be about the same (except the newer version has better performance probably) :

1 - 5 +/- Vccs DC = +/- 0.340V

2 - 6 +/- Vref DC = +/- 0.383-0.384V

3 - 7 +/- Vshunt DC = +/- 0.334-0.333V

4 - 8 +/- Vout DC = +9.5/-8.58V

Thanks anyway for taking time to answer !

Stéphane.