XPS 435T/9000 won’t power up normally- fan noise 3-5sec then nothing

Question

Beginning ~10 days ago, 14yo 435T startup became inconsistent - eg fan, light, drive appeared to be starting after pressing start button but then everything stopped after ~3-5 sec.

- Sometimes a 2nd attempt 1 min later would start up & perform normally.

- Now, 80%of time it won’t make any noises: fan, drives, power button light.

- When it does run now, it will perform normally until I lock to leave idle, then when I return ~2hr later it had powered off.

- I experimented by performing a Restart while operating normally, and it powered off as attempting to go thru startup - similar to fan running 3-5sec then power gone.

I tested with alternate power supply - no change. Have been using Corsair TX750 for 9 yr. Tried replacing with the original Dell PSU - no impact.

Also replaced the CR2032 battery- no impact.

Thanks in advance for any recommendations to revive this 14yo workhorse

Dave9000 · Accepted Answer

SOLUTION: Replaced the top cover panel that includes the power button and the 435T/9000 powered up!

Read similar issue/resolution in another thread so I ordered $14 top panel off ebay.

Prior to receiving the replacement top panel, I decided it was time to retire the 435T and ordered an XPS 8960 from the Dell Outlet. Oh well - if anyone needs parts from the 435T...

smokeygraypoupon · Answer

If I understand correctly, you tried two different PSUs, the original 14 year old Dell PSU and a 9 year old Corsair TX750?

Both these PSU may be at their end-of-life. You might try using a not too old, good quality, known good PSU to rule out the PSUs as causing the issue. Borrowed if possible. I would not even install the trial PSU, leaving it outside the case to test.

Hope this helps.

Dave9000 · Answer

@smokeygraypoupon​ Thanks - Correct - I installed the TX750 9yr ago.  The original Dell PSU was still working at that time so I saved it unaware of potential shelf-life limitations.  I’ll attempt to borrow a known working PSU for a more definitive test.

smokeygraypoupon · Answer

I am not an expert by any means but from what I read the electrolytic capacitors in PSUs degrade over time.

Maybe a more knowledgeable poster can offer additional advice and assistance. I hope it is simply a PSU issue.

redxps630 · Answer

try clear cmos settings via motherboard jumper.

replace cmos battery merely recharges cmos but does not clear cmos

remove cmos battery does not always clear corrupted cmos.

you seem to have ruled out a bad psu.

Dave9000 · Answer

Thanks for the input!

Confirmed the TX750 PSU still works by installing it in separate PC and successfully starting up the 2nd PC.

On the 435T/9000 I used the “JBAT1” jumper pins - removed from pins 1-2, briefly attached to pins 2-3, then returned to pins 1-2. I did not see motherboard jumper labeled CMOS as I’ve seen in similar discussion threads, so I assume this was correct process.

redxps630 · Answer

https://m.youtube.com/watch?v=BlWl4NItjUQ

Dave9000 · Answer

The jumper I used is the same relative position as shown in diagram/YouTube video above. On my motherboard it’s labeled JBAT1 and even though mine has 3 pins, they aren’t labeled 123 as shown above. I have the original motherboard so perhaps it was an earlier version and minor label variations?

I repeated the clearing of CMOS (with JBAT1 jumper) and got a similar result:

- fans &lights kicked on for a couple seconds as I pressed the power button then everything stopped.

- ~5seconds after I released the power button, the fans/lights started again and then everything stopped after ~2seconds.
- Subsequent attempts with power button generated no fans/lights

Any additional thoughts appreciated -

smokeygraypoupon · Answer

@Dave9000​  Delighted you solved the mystery. I believe you will find your new machine a more than capable replacement for your now retired 'workhorse'.

XPS Desktops

XPS 435T/9000 won’t power up normally- fan noise 3-5sec then nothing

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