LH Research PSU faulty?

[pentium]

Inside my personal Iris is this beast of a power supply.
While output voltages are normal I have reason to believe that the lines are very noisy and it's interfering with the scsi controller.
From my view, only one of the yellow Elna caps look bulged but it's hard to say as I have never worked with this kind of power supply and I can't test the system using a regular ATX PSU since I don't have anything that can output the juice this gives out. The system worked fine...before it was put into storage for six/seven years.

[PeteS in CA]

Re: LH Research PSU faulty?

That P/S may have an interesting history. The large I/P lytics are mid-1988 vintage. OTOH, those low ESR Elnas and that one low ESR UCC (bright orange, probably RX or RXA series) are mid-80s vintage. I wonder if the P/S was built in the mid-80s and repaired/upgraded in the late 80s. Regardless, 19+ years old is pretty old for lytics.

[pentium]

Re: LH Research PSU faulty?

According to the stamp on the case the system was assembled in 1989.
Some of the older Professional Iris systems use power supplies from the same manufacturer and quite a few of them are starting to get cranky.
If I had a scope I would be able to investigate.

BTW, my dad remembers when his office first bought it. It cost them $20000 and they never really used it.
I have wanted this system since I was eight.

[tvtech]

Re: LH Research PSU faulty?

Replace those elna capactors,they are probabaly leaking,they leak just like the old nichicon capactors of the same time.Yes elna capactors are reliable but these series are known to be leakers.

[tvtech]

Re: LH Research PSU faulty?

Oh yes I didn't notice it before but that green nichicon capacitor is also probabaly leaking.It looks like this power supply was made by power one which made good power supplies but these old caps are usually the problem.I have seen these caps leaking in power supplies and certain high end monitors and tv's from 1993 and back.

[pentium]

Re: LH Research PSU faulty?

I see no traces of leaking but whatever.
Wow. Tho$e babie$ are $pecial order in the$e part$.

Can any of the more senior members back up what this newb is telling me?

[gonzo0815]

Re: LH Research PSU faulty?

I think the message is clear, w/o any ripple or ESR measuring, the only choice is to replace those lytics.
If you wanna stick to the original style capacitors, then i will be just an expensive repair.

May be you can fit two 4700uF Samxon GD or GC or any other low esr cap with this capacitance in there.
This would make it an ugly but reasonably economical repair. From a practical point of view, this would improve ripple beyond the factory value.

[PeteS in CA]

Re: LH Research PSU faulty?

pentium, getting some LXZs or PWs from Digi-Key should work. Modern low Z parts will be better than late 80s vintage low Z parts.

[kc8adu]

Re: LH Research PSU faulty?

pentium, getting some LXZs or PWs from Digi-Key should work. Modern low Z parts will be better than late 80s vintage low Z parts.

i use fc with no problems.
that type of psu is used in industrial equipment i service.
those yellow elna's will stink bad when desoldered

[PeteS in CA]

Re: LH Research PSU faulty?

In my haste this AM, I forgot that D-K also carries Panasonic FC. PW, FC and LXZ are pretty much equivalent series.

[tvtech]

Re: LH Research PSU faulty?

i use fc with no problems.
that type of psu is used in industrial equipment i service.
those yellow elna's will stink bad when desoldered

Tell me about it.............they smell worse than the nichicon caps..lol

[pentium]

Re: LH Research PSU faulty?

Before I do that I think it might be worth a try to adapt a regular ATX power supply to work in the system. It's going to mean I have to tear apart my pc to get a powerful enough PSU but I don't want to get the parts and then find out that it was not the power supply.

[tvtech]

Re: LH Research PSU faulty?

I would try to find a replacement psu...Down here we have surplus supply houses,I bought a psu that had those output ratings/voltages and was an open frame type like yours for less than 25.00 a few years ago,they are common for industrial equipment so if you have a supply house anywhere nearby you could look there first.

[pentium]

Re: LH Research PSU faulty?

Good luck there.
If it was in an SGI, chances are that you will only find it in an SGI.
These systems are hard enough to find. Finding just the power supply will be next to impossible.

[kc8adu]

Re: LH Research PSU faulty?

I would try to find a replacement psu...Down here we have surplus supply houses,I bought a psu that had those output ratings/voltages and was an open frame type like yours for less than 25.00 a few years ago,they are common for industrial equipment so if you have a supply house anywhere nearby you could look there first.

i get those in bulk real cheap at mendelsons.loaded a shopping cart last time i was there.
problem is you have to recap them even if new in the box.
its the age of the bungs that make them leak.
and a new one is costly.
just recap yours and foget it another 15 years.

[tvtech]

Re: LH Research PSU faulty?

I got lucky the one I bought was within the last 10 years and they were nippon capacitors. Pentium,does your power supply have any outputs for power good or sense??If not than it should be easy to wire a modern atx power supply that can supply that much amperage for testing,If so then you are lucky I couldn't do that with my DEC ALPHA axp server,that power supply was impossible to find and that power supply had management circutry so testing with a substitute supply was impossible.

[tvtech]

Re: LH Research PSU faulty?

I got lucky the one I bought was within the last 10 years and they were nippon capacitors. Pentium,does your power supply have any outputs for power good or sense??If not than it should be easy to wire a modern atx power supply that can supply that much amperage for testing,If so then you are lucky I couldn't do that with my DEC ALPHA axp server,that power supply was impossible to find and that power supply had management circutry so testing with a substitute supply was impossible.

Never mind.....I checked out the link you posted,now you just have to find a psu with enough output,cool site I see some stuff on there for my alpha

[pentium]

Re: LH Research PSU faulty?

Actually I did just try to wire up an ATX power supply and All I got was a fan and no activity from both the monitor or the diagnostics port.
I'm going to have to get a scope. What kind of used scope would you recommend me?

[tvtech]

Re: LH Research PSU faulty?

Darn.....that sucks..Go look on ebay for an older tekronics scope,not anything expensive a 20 mhz scope with probe should do.Maybe someone on here has one to sell for cheap.But most likely the cost of the capacitors is less than the cost of a scope.

[gonzo0815]

Re: LH Research PSU faulty?

A scope is fun, i bought an very old one from ebay at abouth 40€ It is an Hameg HM 312, very basic but nevertheless it is ok for usual ripple measurement.

Tektronic`s are very good, but it really would not mater for this kind of use.

Anyway, for recapping it is not really necessary.