Indigo R4000 power supply repair PEC4044B 6064459

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Daniel80486
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Indigo R4000 power supply repair PEC4044B 6064459

Unread postby Daniel80486 » Thu Jun 01, 2017 8:49 pm

A few days ago, I bought an Indigo CMNB003B from someone through Craigslist. He said it powered on and plays the chime. We met and he attempted to demonstrate, but the Indigo would not power on. He said it worked earlier in the same day, so that was probably the power supply's last hurrah.

Upon turning the switch off, the power supply exhibited a high-pitched whine for about 10 seconds.

Specifically, this power supply is the ITT Power Systems Model PEC4044B, part number 6064459 Rev. A.

I know that other Nekochan users have reported successful PSU repairs by replacing every electrolytic capacitor. I decided to do the same, but took the opportunity to use a piece of test equipment called the Huntron Tracker to look at all the semiconductor devices while the PSU was apart. I found a Zener diode on the rectifier board, CR111, that looked bad.

Previously, user snowolf encountered the same faulty diode in his Indigo's power supply:
http://forums.nekochan.net/viewtopic.php?t=16723677

It is a 5 Watt 15V Zener diode, part number 1N5352. Athough mine was not physically damaged like snowolf's, it's faulty, as shown in this photo comparing it to a good Zener. The one on the right is the faulty one. The x-axis is voltage and the y-axis is current, so the screen shows that it is almost completely shorted, as current goes towards infinity as voltage increases. Compare it to the nice one on the left, that draws zero current until breakdown, as expected.
good and bad zeners.jpg


Here's a shot of the disassembled PSU. I don't know the correct names, but I call the PCBs the rectifier board (left) and controller board (right). The thing on the left is a heatsink with CR107, CR108, & thermal switch TS101 attached. It's from the rectifier board, and I took it out to get to the components underneath.
CAM00086.jpg


Here's a zoomed in shot of the rectifier board, showing the location of the diodes. You can see some of the green solder mask missing. I'm not sure if this was caused by Zener CR111 overheating, or capacitor C127 leaking. Perhaps one component failed and damaged the other, as they are connected electrically.
CAM00092.jpg


To summarize, I reinstalled the PSU after replacing the capacitors and the 1N5352 (CR111), and the Indigo powered on and made the chime. This is my first SGI machine, and I'm still awaiting a monitor adapter and peripherals to test it further. It is possible that the power supply still has problems. If so, I will report back and update.

So, if you're going to attempt a capacitor swap to repair this particular part number, I'd go ahead and replace CR111 while you're in there. It only cost me about $0.50 USD at Mouser.

If interested, I could post a parts list for all the capacitors.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby robespierre » Thu Jun 01, 2017 10:32 pm

The shotgun approach of replacing all the electrolytics may not be the best, but as long as you use components with appropriate specs it may be the most expedient. What happens is that electrolytic capacitors dry out twice as fast for every 10°C above room temperature (Arrhenius equation). Three factors make them especially vulnerable: 1.) small size, since there is less electrolyte to start with; 2.) heat from nearby components, like heat sinks, power resistors, and transistors; 3.) high ripple currents, as when they are used for smoothing in switch-mode supplies. For most capacitors in a power supply, both high temperature rating (105°C or higher) and high ripple current rating are needed. Most also benefit from low ESR rating, but not all: certain regulators need higher ESR in the circuit for stability.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby dexter1 » Fri Jun 02, 2017 12:44 am

Daniel80486 wrote:If interested, I could post a parts list for all the capacitors.

By all means, please do. I can put it on the Nekochan wiki to preserve this information for future repair attempts.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby jan-jaap » Fri Jun 02, 2017 1:30 am

robespierre wrote:For most capacitors in a power supply, both high temperature rating (105°C or higher) and high ripple current rating are needed. Most also benefit from low ESR rating [...]

Panasonic FR series fit this description. Plus they're readily available and not expensive.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby Daniel80486 » Fri Jun 02, 2017 8:53 am

The dimensions given were measured from the original parts, so they may vary slightly from manufacturer specs. Any major differences are noted.

The MFR and P/Ns listed are replacements I picked. I like Nichicon, so that's what I went with. I'm sure it would be pretty easy to use something like Mouser's part selector to find Chemi-con or Panasonic capacitors instead. All the ones I picked are rated at 105°C, except for C105, which was an oversight on my part. My priority was getting everything from one vendor, then I attempted to sort the Nichicon parts by longest rated service life. I'm sure someone willing to put in more time could take my dimensions/ratings and find better parts (10% instead of 20%, longer service life, etc.). :D

Rectifier Board:

Code: Select all

ID        Cap.      Rated V   Diameter   Length  Lead Spacing   Mfr.       P/N
C105      2.2 uF    400 V     10.25 mm   13 mm   5 mm           Nichicon   UVR2G2R2MPD1TD
C106      47 uF     25 V      6.3 mm     12 mm   2.5 mm         Nichicon   UPM1E470MED
C118      3900 uF   10 V      12.5 mm    39 mm   5 mm           Nichicon   UPW1A392MHD
C119      3900 uF   10 V      12.5 mm    39 mm   5 mm           Nichicon   UPW1A392MHD
C120      3900 uF   10 V      12.5 mm    39 mm   5 mm           Nichicon   UPW1A392MHD
C121      3900 uF   10 V      12.5 mm    39 mm   5 mm           Nichicon   UPW1A392MHD
C127      120 uF    35 V      8 mm       12 mm   3.5 mm         Nichicon   UPM1V121MPD
C108      1200 uF   200 V     30 mm      50 mm   10 mm          Nichicon   LGW2D122MELA50
C109      1200 uF   200 V     30 mm      50 mm   10 mm          Nichicon   LGW2D122MELA50

NOTES:
UVR2G2R2MPD1TD is rated at 85° C
UPM1V121MPD is 3mm taller than the original (15mm vs 12mm). There were no clearance issues.
LGW2D122MELA50 is 25mm diameter, instead of 30mm of the original.



Also, there are 2 film capacitors on the rectifier board. It may not be necessary to change them, but I did anyway:

Code: Select all

ID        Cap.      Rated V   Lead Spacing   Mfr.       P/N
C101      1 uF      250 VAC   27.5 mm        Vishay     F17725102000
C140      1 uF      250 VAC   27.5 mm        Vishay     F17725102000

NOTES:
F17725102000 is the exact P/N from the original and is still available.



Controller Board:

Code: Select all

ID        Cap.      Rated V   Diameter   Length  Lead Spacing   Mfr.       P/N
C232      22 uF     25 V      5 mm       11 mm   2 mm           Nichicon   UPW1E220MDD
C233      1000 uF   50 V      16 mm      31 mm   7.5 mm         Nichicon   UPJ1H102MHD
C235      4700 uF   16 V      18 mm      36 mm   7.5 mm         Nichicon   UBT1C472MHD
C236      47 uF     25 V      6.3 mm     12 mm   2.5 mm         Nichicon   UPM1E470MED
C253      22 uF     25 V      5 mm       11 mm   2 mm           Nichicon   UPW1E220MDD
C259      22 uF     25 V      5 mm       11 mm   2 mm           Nichicon   UPW1E220MDD



Finally, the bad diode: CR111, replaced with an ON Semiconductor 1N5352BG.
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dexter1
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby dexter1 » Fri Jun 02, 2017 10:42 am

Excellent work. I'll put it in the Wiki tonight.

UPDATE: Done, it's added here
Please check if i have copied everything correctly.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby japes » Fri Jun 02, 2017 11:06 am

Thank you!

My Indigos are pretty far back in the queue for getting attention, but when I get to them I'm sure this will be helpful. I remember powering one on to the smell and sound of something popping - it still ran but it has made me worried to run these systems.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby kjaer » Fri Jun 02, 2017 4:41 pm

This is timely. I've a couple failed Indigo PSUs that I've needed to look closer at.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby Daniel80486 » Fri Jun 02, 2017 8:18 pm

dexter1 wrote:Excellent work. I'll put it in the Wiki tonight.

UPDATE: Done, it's added here
Please check if i have copied everything correctly.


It looks OK, just might want to clarify that the temperature ratings are for the replacements I chose, as I tried to stick with 105°C rated components.

The originals were various ratings, mostly 85°C. I don't have the old ones with me at the moment, but if it would be helpful, I could post the ratings of the originals on Monday.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby kjaer » Sat Jun 03, 2017 9:46 pm

That's brought one of them back to life, anyway. Cheers!
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby johnnym » Sun Jun 04, 2017 1:42 am

Daniel80486 wrote:Upon turning the switch off, the power supply exhibited a high-pitched whine for about 10 seconds.

After you have repaired the PSU, is that "high-pitched whine" sound after turning the switch off gone now?

I have an Indigo which is currently not in working order because of ripped/missing parts, but it's PSU seems to work when attached to the backplane and switched on. Upon turning the PSU's switch off, it also emits a sort of high-pitched whine or "squeak" like sound, but only for a short moment. Dexter1 also has this with his Indigo, so it might be perfectly normal, but could be related to what you heard.
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Re: Indigo R4000 power supply repair PEC4044B 6064459

Unread postby Daniel80486 » Sun Jun 04, 2017 3:31 pm

johnnym wrote:
Daniel80486 wrote:Upon turning the switch off, the power supply exhibited a high-pitched whine for about 10 seconds.

After you have repaired the PSU, is that "high-pitched whine" sound after turning the switch off gone now?


Upon turning the switch off, I hear a "squeek" about 1/4 second long, that appears to be coming from the speaker. At the same time, I hear a fainter whine coming from the PSU, lasting about 1 second, decreasing in pitch, in the 10kHz to 20kHz range, like the sounds a CRT monitor might make when powering on or off.
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