Firepower ModXStreamPro (OCZ) Teardown & Repair

[SgtRock]

Greeting Badcappers:

--I bought this non-working unit on eBay for $32.00. Using (see picture) a cheapo PS Tester, I determined that all is working, but the PG (Power Good) light is not working, because, likely due to Bad Caps. Hence the teardown.
--All of the 3300uF and 1000uF caps, though not swollen, are showing increasing capacitance and 0.00 ESR per my Bob Parker Blue ESR Tester, usually a sign that they are failing and going leaky. All of the silicon seems to be fine, so I will completely recap with quality Japanese Caps, and report back. I am going to replace the 470uF 400V 85C with a Nichicon 470uF 450V 105C 3000hr. I have seen this Cap loose capacitance and combined with dust bunnies (see picture) take out the TNY278P Tiny Switch switching regulator and other components. Dominic Chen has developed a partial schematic for the 600W unit which you can see at https://www.dcddcc.com/proj/oczpsu/. To, hopefully, prevent any destructive arcs near the TNY278P, which is close to one of Schottkys, I plan to shied the leads of both with liquid electrical tape. I have seen this done at the factory in other devices.
--I am rather new at this, so your advice and comments are welcome. P.S. Does anybody know how to figure out the date of manufacture. I can see nothing on the circuit board which helps.
Cheers!

[TELVM]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

The design of that PSU is flawed, the +5VSB stuff is poorly placed in a hellish corner with little or no airflow . No wonder the TinySwitch and adjacent resistor bite the dust and burn.








To give these components some life expectancy I'd put that resistor 'on the flying', and would glue a tall heatsink on the TopSwitch to cool it down.

Also cleaning the PSU insides from time to time wouldn't harm.

[SgtRock]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

Dear Telvm:
--Good comments. Oddly enough your last two pictures are from a teardown and repair I did of a 600W unit. I will eventually post that repair here. In that repair, the large smoothing cap had lost significant capacitance. Luckily I only had to replace the switcher and resistor, I also recapped with oversize and overvolted Japanese caps and covered the leads of the switcher and adjacent schottky with liquid electrical tape. It is still going strong, and is gathering no dust as yet, but I will check periodically.
Cheers

[CapLeaker]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

"are showing increasing capacitance and 0.00 ESR per my Bob Parker Blue ESR Tester"

I never had that ESR tester in my hands, but either this sentence isn't right, or the caps are so bad due to such high ESR that it is out of the testers range. Are you testing ESR alone or are you testing DCR and ESR?
I have a different one and I know that the ESR is really high if the tester doesn't do anything at all.

[stj]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

i'v seen those readings a few times.
yesterday, i had a 3300uf cap saying 9800uf esr 0.00

i dont know the reason, but i know that cap is going in the bin!

[SgtRock]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

Dear CapLeaker:
--Good point I had a problem with my capacitance meter ($16 special). My friend checked with a BK and they all are above nominal but within tolerance, some just barely. The Bob Parker Blue is well thought of and recently calibrated. If I short the leads, I show 0.08 Ohms ESR. If I then test them (after zeroing or not zeroing the meter) it reads 0.00. These caps seem very light, as if they are dried out. My Fluke 87 multimeter shows them charging up just the same as new ones. The ridiculous result of 0.00 ESR leads me to believe the caps are bad, possibly due to leakage, but I am no expert. I might add I have seen this before and the caps were bad. As I understand it the Bob Parker Blue measures the Total of DCR plus ESR, but like I said I am no expert, and I mostly work at the level of monkey see monkey do parts changer, which often works.
--They are all Teapo brand, so I would be replacing them even if the PS was working. If you would like I could send you, or anyone else, a couple of them, just PM me. When my Digikey order arrives, I will install with all new, and we shall see. I note that I can no longer find a source for 12.5mm 3300uF Panasonic series FC caps at Mouser of Digikey and so I have ordered Nichicon PW. By the way I cannot find any 10mm diameters at all.
Thanks

[SgtRock]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

Greetings Badcappers:
--Well, I reassembled this PS with all over sized and over voltaged caps, wherever possible. The Rec 85C 400V 470uF main smoother was replaced by a Nichicon 105C 450V 470uF that was 5mm wider. To make it fit I had to cut one of the anchor pins, and bend over the steel holddown of the adjacent heatsink. Rubber and liquid electrical tape was used wherever needed to insure against shorting. See pictures.

--When it started up, it still had no PG (Power Good) light. My Fluke 87 DMM showed that the Grey Power Good wire, had zero instead of 5V. I had throughly checked all the main through hole components, so I guessed the problem was in the SMDs on the bottom side, which I checked as best I could with SMD tweezers. In this I was greatly aided by a post by Agent24 https://www.badcaps.net/forum/showthread.php?t=37649. I rechecked the components he pointed to, and found that indeed SMD diode D308 was shorted. I replaced it with a boged through hole 1N4148, and voila, shes a fix. Kudos to Agent24.

--The OCZ MODXSTREAM-PRO series are very well built. The problem lies in the use of Rec, Teapo, and (gag) Suscon caps. I have two more which are running just fine, that I also plan to recap. So whenever I replace a PS for myself, or friends and family, I am confident that it should last at least 5 years with ocassional dusting. Also using only one design of PS, makes repairing and recaping a breeze, because I am getting very familiar with them. So I have been buying any that are used or non working, if the price is right.

Cheers!

[SgtRock]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

Pictures attached to this post have disappeared. I have resized downward, but now can find not way to reply other than quick reply which will not let me attach pictures. Help!

[Per Hansson]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

You should have the "Go Advanced" button right next to the "Post Quick Reply" which will take you to the full page post editor.
There should also be a button saying "Post Reply" to the left right the user name below the last users post which will take you to the same page.
In both cases you need to be logged in of course.
The large images do load a bit slow, but when our server move gets finished that should improve so don't sweat it

[SgtRock]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

Thanks Hansson:

--My original picturea at beginning of this thread have disappeared, and I have lost the originals. So I am posting the 800 x 600 of the repaired unit here below.
Cheers!

[SgtRock]

Re: Firepower ModXStreamPro (OCZ) Teardown & Repair

Dear Hansson:
--Pictures have reappeared. Many thanks again!