headbuttking2

I have just acquired a 1500 V variable power supply by KEPCO Labs that I am going to use to build/test tube amplifiers..
This thing is huge and is constructed of tubes..

The model # is 1220C and Serial is B-30345

Now my problem is that there are B- and B+ terminals..
Someone machined a BNC plug into the B- port and over the B+ port it says "NC" in marker...

All I can get out of this is a negative voltage (The unit seems to work fine if I want a negative voltage).

The positive terminal must be connected to ground inorder for it to operate..
The positive terminal is connected to the CURRENT meter also.

Here is where I don't understand..
There are massive grey blocks on the chasis..
I can only read one and it says 4 uF at 1000 VDC or 450 VAC, so I don't know if they are all capacitors or inductors. There are 2 smaller ones in the circuit, then the 2 massive ones are on the output. The larges one which is about twice the size of the 2nd largest one produces a negative voltage from a positive one (it has a 1M Ohm resistor across its terminals)..

This is what I observed when I traced the output:

The largest grey block ( I was able to read 4 MFD on the bottom and on the top I can make out "INDUC") has a voltage around 600V on it and as you increase the unit this voltage decreases. There is also a 1M ohm resistor between the terminals of this block.
The 2nd terminal of this block is connected to the negative terminal. This 2nd terminal is also connected to a 2nd grey block. The opposite terminal of this 2nd grey block is where the positive voltage should come from.

I believe someone modified this, because there is a red/white wire coming from the 2nd terminal of the 2nd grey block to the B+ terminal. If it was suppose to be ground wouldn't it be black like the rest of the ground cables?

The insides of this unit are not to hard to trace since it is made of vacuum tubes and there are very few parts, so I traced it the best I could.
On Kepcos website they want $100 for a schematic and service manual which is ridiculous.

Sorry if this post is a little confusing but hopefully someone out there knows a little about vintage power supplys and can help me out here.

I was just wondering if there was away for me to get a positive voltage from this from what I described. Or if someone could just tell me what is going on with this circuitry it would greatly help too.

Thanks in advance.

muki55

There's no problem in your power supply. All gray in your power supply are all electrolytic capacitor. The 1m resistor is to discharge the capacitor when not in use. There are no ground in your power supply it's a floating ground. Use B- and B+ to your project.