Along with the dead board, I also decided to check on the PSU powering it. To my abject horror, it was the now infamous Powmax. Powmax have occupied a unique niche among power supplies..i.e. they are synonymous with garbage. Most of them are OEM'ed by Leadman Inc and never cease to amaze with premature pyrotechnics.
So, naturally I expected the worst, given this rather less than savory reputation these units have manage to acquire. But, what piqued my curiosity was that this old P3 system was in service for a good 10 years! Surely a Powmax won't last THAT long on a 5V heavy motherboard?!
Well, let us see what is under the hood!
The obligatory rated specs shot:
300W unit, 20A on the 5V, 14A on the 12V and 14A on the 3.3V. Wait, does that even make sense? 100+168+46.2 = 314W peak. Well, at least the label is not too misleading.
There were only two screws securing the hood to the rest of the enclosure. Opened her up and wow! Surprise surprise! A rather decent looking innard for a 300W unit.
Matsushita/Panasonic Primaries rated at 420uF, 200V (This unit has no APFC):
Next question? Who made this unit?
OEM seems to be Leadman, a well known trashy OEM right up there with Deer. But will all the currently accrued negative press have a bearing on how this unit was built? Let us see!
Does the unit have independent regulation? Look at the Three transformers on the primary side. One is a 12V, one is shared by the 3.3V and 5V rails and the little one is the 5VSB transformer. The secondary side however, does not have the requisite filtering stage that is characteristic on an independently regulated unit. So the answer is NO.
The secondary side has...hold your breath! Rubycon on the 12 V and Teapo on the 3.3V/5V Pi filters! Wow! Simply amazing! Totally unexpected! No wonder it lasted this long. Apart from the dust, this unit seems to be in pretty good shape.
Holy mother of God! This is a huge huge surprise....I spotted an MOV! Note that the MOV is long since dead, as evinced by the burn on the PCB (failure mode is a short circuit rendering its clamping action useless), but damn..its mere presense qualifies this unit as the Chuck Norris of Leadman built power supplies!
All in all, it seems like the older Leadman/Powmax units were not as trashy as their current reputation belies. Looks like they started out o.k but lost the plot along the way.
Cheers!
S-N
So, naturally I expected the worst, given this rather less than savory reputation these units have manage to acquire. But, what piqued my curiosity was that this old P3 system was in service for a good 10 years! Surely a Powmax won't last THAT long on a 5V heavy motherboard?!
Well, let us see what is under the hood!
The obligatory rated specs shot:
300W unit, 20A on the 5V, 14A on the 12V and 14A on the 3.3V. Wait, does that even make sense? 100+168+46.2 = 314W peak. Well, at least the label is not too misleading.
There were only two screws securing the hood to the rest of the enclosure. Opened her up and wow! Surprise surprise! A rather decent looking innard for a 300W unit.
Matsushita/Panasonic Primaries rated at 420uF, 200V (This unit has no APFC):
Next question? Who made this unit?
OEM seems to be Leadman, a well known trashy OEM right up there with Deer. But will all the currently accrued negative press have a bearing on how this unit was built? Let us see!
Does the unit have independent regulation? Look at the Three transformers on the primary side. One is a 12V, one is shared by the 3.3V and 5V rails and the little one is the 5VSB transformer. The secondary side however, does not have the requisite filtering stage that is characteristic on an independently regulated unit. So the answer is NO.
The secondary side has...hold your breath! Rubycon on the 12 V and Teapo on the 3.3V/5V Pi filters! Wow! Simply amazing! Totally unexpected! No wonder it lasted this long. Apart from the dust, this unit seems to be in pretty good shape.
Holy mother of God! This is a huge huge surprise....I spotted an MOV! Note that the MOV is long since dead, as evinced by the burn on the PCB (failure mode is a short circuit rendering its clamping action useless), but damn..its mere presense qualifies this unit as the Chuck Norris of Leadman built power supplies!
All in all, it seems like the older Leadman/Powmax units were not as trashy as their current reputation belies. Looks like they started out o.k but lost the plot along the way.
Cheers!
S-N
4 comments:
I owned one and it took out two of my hard drives. Powmax taught me an important lesson about importance of power supplies and what they can do.
How old was it? The one I pulled up still runs, fried MOV and all. Of course this was from say 1995 or so. Perhaps they were o.k back then?
Surely I would never recommend Powmax junk for a modern system!
300 W from 2001 or so.
It is interesting how there is very little data available regarding mass market albeit junk PSU's. I'd like to see when these units dropped off in quality. Which year, I mean.
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