Digi International Portserver 16 rack mount.

[dacflyer]

i have this 16 port server..and the PS is out..
cannot find any information on it.. i'd like to repair it if i can..
i have checked several things, but i am not all that good with SMPS. it is trying to fire up, but then shuts down again.
over and over, a test led i have shows it pulsing. meter is indicating -5 and -12 which does not seem right.
anyone know about these ?
if i could get a schematic of the PS, that would help a lot..

[haklesup]

Are you trying to salvage the server or just the power supply? If you want to use the server, abandon the PS and get an equivalent.

[dacflyer]

wanting to either repair the PS or find a equivalent PS, but i do not know the voltages of the PS.
i need info on it..

[Janitor Tzap]

You got your hands on one of these?

Hmmmm..........

I'd go through the power supplies Electrolytic Capacitors first,
especially those on the 12Vdc & 5Vdc outputs.
Then look at the lower value ones, in the Inverter stage.

I did find this place, that supposedly sells parts for them.
http://www.plccenter.com/en-US/Brand/DI ... id-page=14


Signed: Janitor Tzap

[dacflyer]

they are all fine ( the caps ) the unit went down after a transformer failed for our building..since then it was out..

[haklesup]

"but i do not know the voltages of the PS. i need info on it.."

how many outputs (different color wires) does the PS have. Odds are it is industry standard Black for ground, Red for5V , yellow for+12V and maybe another color (orange) for -12V.

[Janitor Tzap]

Hmmmmmmm...............................................

{Re-Reads original post}

SMP pulsing would indicate a short in the load circuit.

Was other equipment damaged, that had been connected to the Portserver?

If the answer is yes.
Then I'd just replace it.
Because repairing the burned out LAN port interfaces would cost more than a new Portserver.


Signed: Janitor Tzap

[dacflyer]

colors are black , white red, green on PS...

pulsing still continues even is the load is disconnected...
no other equipment was damaged.

[Janitor Tzap]

Sorry,
I was trying to attach a PDF to this thread, but for some reason it wouldn't do it.

Anyway.......

I found T.J. Byers article on SMP Power Supply Repair.
https://www.scribd.com/document/2106350 ... pair-Guide

It may be of some help too you.


Signed: Janitor Tzap

[haklesup]

"colors are black , white red, green on PS..."

Are you counting the AC input too or are all those outputs?

if outputs, I might guess that Black and Red are the 5V output, green is passive ground and white, that's an oddball, maybe a control line for turning it on and off. A photo of the PS components would be helpful.

Which wires had the -5V and -12V pulsing and what was the ground reference?

Pulsing indicates shutdown of the output due to a fault condition. After eliminating a shorted load, clearly the failure is internal. However it could be the IC that controls the SMPS is bad and not processing feedback correctly or that the feedback is returning the wrong value.

When the building xfmr went down you may have had a voltage spike or a sag. Did you already check the MOV and protection components at the AC input. The MOV can be cut right out and it should still work, it just shorts if a voltage spike hits. Usually the MOV burns and the fuse blows but other things can happen. It shouldn't cause your symptoms but should also be checked given the failure cause.

http://www.barcodegiant.com/digi/part-76000694.htm

Capacitors may be bad without showing physical clues. high ESR can develop over years of use at elevated temperature without discoloration or signs of overheat.

[dacflyer]

will check more, but ya,, the wires were all output,, no inputs..
and all outputs were pulsing.. i checked various items of common failure, i can only guess it is a IC from this point..

[haklesup]

for more modern SMPS designs, there are lots of app notes at the chip makers websites but for models 10 years old (less efficient older models) you may have trouble finding as much documentation. Start with that IC chip part number and if you can find a datasheet it should lead to an example circuit that should be substantially similar to what you have.

Current limit circuits are often responsible for output collapse but these would be integral to the feedback in the SMPS design. The IC is probably the most susceptible part to be damaged in a power surge, too bad the MOV and fuse didn't catch it or perhaps its time for external surge protector replacement or upgrade. A UPS would probably have saved that server.

[dacflyer]

it was in a large UPS, the unit was in use in a large mainframe,
we have about 5 UPS's in use.
i think i can figure out the power..i guessed the black was gnd, but when i touch other wires, i get a -5vdc and a -12vdc , but i know it should be a pos. voltage.
i read documentation on the unit, but i do not know what it is talking about when it says like 45v and 90v..
if it really is 5 and 12v, then i can try a old computer PS. of course it would be way overkill.. when a small brick might work.

[haklesup]

We normally think of a power surge damaging equipment through the power supply but in this case if the PS went low enough but the Ethernet cables were still powered from the other end, then you could easily have a situation where the cables were higher voltage than the equipment allowing a back current into the server taking out channels and the PS. However you can't know if any channels are fried until you fix the PS. Now there shouldn't be enough power in an Ethernet cable to take out a PS but the surge condition could have done some strange things.

[dacflyer]

meaning ?
the unit was replaced, and everything works.. i am just trying to salvage the old one...if possible..