[time-nuts] Re: Need help to DATUM Power Supply MPS (Type MFS Modular Frequency Systems)

[Wilko Bulte]

Quoting jung.schorndorf--- via time-nuts, who wrote on Thu, Jun 09, 2022 at 04:26:08PM +0200 ..

hello Helmut,

> power supply unit for the GPS frequency standard
> from DATUM (Type MFS Modular Frequency Systems), I visited your homepage and
> registered on "time-nuts" mailing list.
> .
> May I ask if you have a frequency system like this with better documents
> than I do?
> The problem is the defective mains transformer in the Power Supply MPS
> module. I'm looking for the data (voltage & current)
> to find the right one from my transformer collection.
> I can only measure a few coil resistances on the transformer, the primary
> coil doesn't work at all.

> Also, maybe someone has the circuit of the electronics board.
> Our German subsidiary DATUM-Symmetricom-Microchip no longer since 20 years
> has any documents.

I have been looking for the same information in every corner of the Internet
but never found any schematics unfortunately..

But I happen to have the same PSU, a bit older even, as it is labeled
Efratom. A working one fortunately!

So, worst case I can open it and measure the voltages that the transformer
produces. It is not a lot of fun to open it (I had to, it had a loose screw
rattling inside or something like that) but it is doable.

If I remember correctly it produces 18V (AC? not sure) for the oven heater, 
the rest of the MFS runs on 22.5V DC. There might also be 5V DC involved for
the MGPS (GPSDO module).

MfG,

Wilko