FUG HCN 14-12500, High Voltage Power Supply repair

[HighVoltage]

I got this FUG HCN 14-12500, High Voltage Power Supply for free but it is broken and does not work at all.

This PSU can supply 12.5 kV at 1 mA, is "Made in Germany" and is very well built.

So, may be this repair is interesting for some people here at eevblog.

Symptoms so far:
- Does not turn ON
- Voltage regulator knob broken

When I opened it up, I saw the high voltage polarity switch broken. It looks like the instrument fell down.
So, I need to get a new plexiglass tube made first.
 


 

[xrunner]

I got this FUG HCN 14-12500, High Voltage Power Supply for free but it is broken and does not work at all.

This PSU can supply 12.5 kV at 1 mA, is "Made in Germany" and is very well built.

So, may be this repair is interesting for some people here at eevblog.

Absolutely will be interesting. 

[vindoline]

It looks like a beautiful piece of gear. Looking forward to the story...

[Armadillo]

Where it came from : Electrocution Chair?
Man I won't be playing with this thing.

Anyway careful and Good luck with your repair.

[SeanB]

12kV 1mA, perfect low current supply for things like PMT units and electrophoresis use, but not going to do much more than give you a long lived respect for high voltage..

Now the 14kV 30mA neon sign transformers I have are a totally different thing, they are definitely capable of killing you if you are careless. They even have bare mains connections, using the same insulators and bolts as the high voltage side, but the one is a later unit with a interlock shroud over the HV and LV connections. The electronic one i rescued at the scrapyard has built in non replaceable wire leads input and output though, so it drives the display on the wall.

[HighVoltage]

Ok, progress is slow on this repair because it requires some odd parts.

The broken Plexiglass insulator tube for the polarity change had a very odd dimension and was difficult to obtain. But a German made 50 mm diameter and 4 mm wall-thickness works. I finally found a supplier and today I cut and drilled the tube to the dimensions of the old one.

The small outside threads are M2.5
And for some reasons I thought the larger brass insert threads are M8x1
But they are M8x0.75, so I have to order a new tab before I can continue.

[HighVoltage]

For anyone playing along at home, I got the User Manual (German)
The schematics and service manual are promised to arrive from the German manufacturer soon.

[HighVoltage]

WORKING!

- New High Voltage insulation Tube installed
- New outer insulation tube installed
- 2 x new multi turn 10 k potentiometer installed
- 12V voltage regulator replaced
- Several electrolytics replaced
- Calibrated

Both, positive and negative is working.
So the few hours of work on the polarity switch have paid off.

I can only test to 5 kV at the moment with my high voltage DVM
And I need to get an original LEMO high voltage connector, before I will take it to 12.5 kV
And this connector is probably very expensive !

[HighVoltage]

I finally manage to get an original LEMO high voltage connector for the power supply. It is probably the most expensive single connector I ever bought, at 75 Euro. But ... it is excellent quality, as expected from LEMO and fits perfectly to the instrument and cable.

Here are some pictures of the cable and connector.

[Czucky]

Hi, I have bought a FUG power supply also. Have received the 3S Lemo Connector from the seller and looking for a cable for tests, like the one on your pictures. Can you tell me how you built the cable with the Lemo connector and the two 4mm pins ? Thanks in advance for your reply.

[HighVoltage]

Czucky,
You need to use shielded high voltage cable.
The inner conductor carries the high voltage and the braided shield of the cable is ground.

Connect the red cable and banana plug to the inner conductor and the black cable to the shield
Use large enough distances and good quality shrink tubing
 
Enclosed is a pdf to show the correct assembly of the LEMO connector (German)

[Zucca]

 

[Czucky]

Thank you HighVoltage, I send you an PM. 

[popei69]

Hello,

I´m also need a high voltage cable with hv-connector to -/+ splitted output, see in the attachment. Can anybody help?

thx

[HighVoltage]

These old proprietary Philips connectors will not be available anywhere unless you find an old stock from the 1970s and that is very unlikely.

I would replace them with modern SHV connectors, which are good for up to 5 kV.
They are easy to get in good quality and its easy to make a cable for.

[popei69]

thx, sound good... i sent you a pm

[htm]

Hi HighVoltage,

This topic has been quiet for a while, but, i'm interested in that tube. Can you explain what it is for?
(i came acros this post because your device was mentioned in following patent https://www.freepatentsonline.com/5048458.html )

Kind regards

[HighVoltage]

Hello htm

The tube is for changing the polarity of the output for both output wires.

So, you can have:

+ / -
- / +

[MathWizard]

So what would happen if you put your finger across 12kV ? What about each hand across it ?? Play it safe.

I have a couple of old CRT scopes, IDK how their HV is doing, but I'm not in a rush to find out.

[HighVoltage]

So what would happen if you put your finger across 12kV ? What about each hand across it ?? Play it safe.

I have a couple of old CRT scopes, IDK how their HV is doing, but I'm not in a rush to find out.

If it comes to high voltage, I have been zapt many times by spark voltages with relative low energy and only a pulse of high voltage.
Although it feels strange each time, based on my results, it is not very dangerous.

But these high voltage DC power supplies are a different game, I guess.
Luckily I was careful enough to not touch such 12 kV at 1A max current.

My biggest FuG DC power supply goes up to 50 kV and I must say, that I am extremely careful with such a PSU and always work only with one hand at the time. These are not toys!