[time-nuts] Robert G8RPI -- Odetics 325 PSU

Roy Phillips phill.r1 at btinternet.com
Sat Apr 19 18:34:18 UTC 2008


Robert

Thanks for your comments on the PSU, and I would certainly agree with you 
that they are nasty beasts to work on, and I cannot find a faulty component 
yet !    But I am fortunate in having been offered another  325, this I will 
have to wait for, but in the meanwhile I have a brand new (different 
manufacturer) SMPS to hand, and will use this in the short term. I had 
thought that to maintain the "support" DC supply circuitry that is part of 
the original PSU, was a good idea, as my Ball/Efratom Rubidium has its own 
24 volt support system - but this could obviously be achieved another way.
I must say the 325 had begun to settle down and perform very well - I still 
think that its a worthwhile unit.

Best regards

Roy

----- Original Message ----- 
From: "Robert Atkinson" <robert8rpi at yahoo.co.uk>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, April 19, 2008 7:04 PM
Subject: Re: [time-nuts] Robert G8RPI -- Odetics 325 PSU


> Hi Roy,
>  I've looked at two of these PSU's that had failed and was unable to 
> repair either of them. (I'm a professional electronics engineer and can 
> fix most things) There were no obvious faults like leaking capacitors or 
> burnt up components. The topology of the auto-switching between 28V DC 
> and 115/230V AC is not obvious and the PCB is very densely packed making 
> it very hard to trace the circuit or make measurements. The high voltage 
> on the PCB makes it hazardous to work on. I gave up and replaced them with 
> a standard mains input multi-output unit. I don't recall the voltages and 
> ratings (they were marked on the unit), but if you let me know what they 
> are I'll see if I have a suitable unit. email robert8rpi (at) yahoo.co.uk
>
>  Regards,
>
>  Robert G8RPI.
>
> Roy Phillips <phill.r1 at btinternet.com> wrote:
>  Hi Robert
>
> You may remember that we exchange info on the 325 SatSyc Receivers. I 
> remember that you said that the PSU was a weak point with the system - you 
> were right on , after finding a suitable antenna and replacing the lithium 
> battery in the Rx., it was running sweetly for about 18 days, but 
> yesterday it failed. The power fuse (AC input) had blown, and following a 
> quick inspection within the PSU - nothing appears to be burnt out or 
> visibly damaged. What was your experiece of fault finding with this item. 
> Before I proceed further, do you have the schematic for the PSU - this is 
> not in the normal manual - its an AC to DC, and a DC to DC unit. Its a 
> quality item, Model VF100 -494-10/CX ,made by "Converter Concepts", and 
> should be worth restoration. Any ideas ?
>
> cheers
>
> Roy UP
>
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