Re: NPS-305CB from Dell Dimension 5000 "dead"

Thanks TELVM for labelling my psu photo so beautifully and informatively!
Probably not on purpose, that would require some forethought; more likely poor layout design or time pressure to get the design to market :-)

Richard...

Re: NPS-305CB from Dell Dimension 5000 "dead"

Yes momaka you are right, right, right!

However, as ever, it's a matter of priorities; I'm making the 2006 Dell Dimension 5000 redundant and just need it to stay alive with minimum effort for about 1 week whilst I extract data from it.

Nevertheless, I'm tempted to explore the SMPS problem(s) further and subsequently may well analyse the psu and practice replacing various capacitors. So what brand of capacitor should I buy here in UK in place of the, allegedly crappy, Ltec brand? BTW, here's a...

Re: NPS-305CB from Dell Dimension 5000 "dead"

Many thanks all for your comments.

1. Following the suggestions of Wester547 and Momaka, I checked +5V SB (pin 9) and found +5.05v (also found +4.68v on "power on" (pin 16)). So as it seemed to me that the SMPS might now be OK, I reconnected the dismantled psu to the mobo etc. and the PC powered up! I'll now reassemble the circuit boards and fan back into the psu housing, refit in the PC tower cabinet and see if my luck continues....

2. STJ - you refer to the "old days"; how...

Re: NPS-305CB from Dell Dimension 5000 "dead"

...yes, but for an SMPS that has no mains on/off switch, isn't there a resistor (around 500kohm) that initially trickle charges the start capacitor when the mains supply is first connected and so enables the control circuit to be able to detect the use of the start button? At all other times the PSU is in standby even though the PC is off?

Re: NPS-305CB from Dell Dimension 5000 "dead"

...... and, if I can eliminate the start resistor (if any), I'll get myself an ESR meter and check out the capacitors.....RG34

Re: NPS-305CB from Dell Dimension 5000 "dead"

Gentlemen, I appreciate your comments and may investigate the capacitors further.

However, before I dismantled the psu, I tried to get it to start up by shorting pin 16 of the 24-pin ATX mother board power supply connector (green power on) to an adjacent ground pin; result nothing and even the fan didn't run.

Meanwhile, can any of you comment on the start resistor - does the NPS-305CB use this method to start from scratch (not standby)? Prior to going on holiday, I had no start up problems with...

Re: NPS-305CB from Dell Dimension 5000 "dead"

Here are various views of the controller circuit board and the mains input circuit board:

[ATTACH]120258[/ATTACH]
[ATTACH]120259[/ATTACH]
[ATTACH]120260[/ATTACH]
[ATTACH]120261[/ATTACH]

Regards, RichardRe: NPS-305CB from Dell Dimension 5000 "dead"

Here are various views of the controller circuit board and the mains input circuit board:

[ATTACH]120258[/ATTACH]
[ATTACH]120259[/ATTACH]
[ATTACH]120260[/ATTACH]
[ATTACH]120261[/ATTACH]...

The SMPS NPS-305CB from my Dell Dimension 5000 PC is "dead". I suspect a faulty start resistor and need advice on how to identify this resistor on the power supply circuit board(s). I suspect the resistor because the PC was unplugged from the mains supply while I was away on holiday and now cannot be turned on. Previously there were no problems turning the PC off via Windows and turning it on via the front cover start button. All of the power supply capacitors look in excellent condition, the mains fuse is OK and there is no sign of any damage to the power supply unit. Regards, Rich...

Re: New Members - please post your introductions here

Hi I'm Richard from London, UK, retired from a lifetime in IT. Found this forum whilst searching for advice on fixing the SMPS of a Dell computer!