Jou Jye JJ-300AP 300w Fail

[kc8adu]

Re: Jou Jye JJ-300AP 300w Fail

some sort of overvoltage to kill all the mov's like that.
open neutral maybe?
i saw that happen at computerfest at hara arena a few years back.open neutral in a power drop killed about 20 machines at once.sounded like july 4 with all the lytics exploding.
stunk up the whole building for hours.lets all the smoke out at once.

[RJARRRPCGP]

Re: Jou Jye JJ-300AP 300w Fail

But the power supply looks like it was well made. It appears to have a nice thick heatsink, which many not-well-known brands don't have. It's constructed similar to an Antec SL 300.

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

some sort of overvoltage to kill all the mov's like that.
open neutral maybe?

hopefully the apc he got will tell if there is a wiring fault. Shouldnt other appliances have been affected though?

One thing to consider is that only one of the mov's is burnt. Is there a possibility that the one mov became off spec? should both have blown or is one normal?

[Per Hansson]

Re: Jou Jye JJ-300AP 300w Fail

One thing to consider is that only one of the mov's is burnt. Is there a possibility that the one mov became off spec? should both have blown or is one normal?

Same thing with the PSU I posted about... Only one Zenerdiode went kaput...

[willawake]

Re: Jou Jye JJ-300AP 300w Fail

user installed the apc and replaced the psu with the fortron. now computer is working fine again.

then if it was voltage surge lucky that the psu had that protection since no ups was installed at that time.

Same thing with the PSU I posted about... Only one Zenerdiode went kaput...

interesting. actually i am learning a lot from this thread.

[AK0R]

Re: Jou Jye JJ-300AP 300w Fail

Would it be repairable if i salvage some varistors from another unit, or would there be more damage?

Not advisable, since MOVs' damage is cumulative. So any damage that they took before would shorten their lifetime in the new application. Also, MOVs don't generally show any signs of degradation until failure. They fail by one of two means: either they open, in which case there is no visible indication, but they no longer provide protection, or they short, and the high current then blows them apart (which appears to be what happened here).

hopefully the apc he got will tell if there is a wiring fault. Shouldnt other appliances have been affected though?

One thing to consider is that only one of the mov's is burnt. Is there a possibility that the one mov became off spec? should both have blown or is one normal?

Because the damage is cumulative, several small overvoltage conditions can cause just as much damage to the MOVs as one large one. Major appliances (refrigerator, stove, etc.) or those with motors are less likely to be sensitive to overvoltage conditions than those with sensitive electronics (microwave, PC, etc.). So, overvoltage conditions could have been occurring relatively frequently without his knowledge. One of the worst is the switching transient that results when an electrical substation drops off or comes on line, or if the transmission system senses a fault, and briefly de-energizes and then re-energizes the line to see if it clears. The switching times are in the millisecond range, but the transients can be huge (>1000v on a 240v line).