Changed CMOS battery on a Dell Optiplex now PC won't power up at all

[kaphc]

I've got a Dell Optiplex SX280 that was reporting system voltage low on the CMOS battery.

 

So ordered a new battery, took out the hard drive very carefully, took out the old battery, put the new one in and reassembled. Found some very helpful online instructions here: Installing Dell Optiplex SX280 Battery - Page 3 - iFixit which I followed.

 

But now I have no power to the PC at all - nada. Switching it on at the power button does nothing.

 

I've tried swapping the old battery back and that has the same problem - no power at all now.

 

Have checked all the obvious things like power cables plugged in at the back of the PC, power cable reconnected to the hard drive etc.

 

This is the first time I've changed the battery on a motherboard and I can't help thinking I must have overlooked something? Can anyone point me in the right direction?

[DrPerceptron]

What diagnostic lights do you have on the machine?

 

Are any of the capacitors fat, bulging or leaking? SX280s are notorious for that.

[mac_shinobi]

Any jumper to clear cmos ?

 

If not take the cmos battery out and try and power it on for a few seconds and then power it down and put the cmos battery back in and try and power it back on again ?

[chazzy2501]

These have an external powersupply don't they? change the kettle lead going to the adaptor and check the cable for damage. Also try reconnecting (if you haven't 20 times by now) the plug in the back.

[kaphc]

Thanks for the tips .... had to move on and look at something else in the end yesterday but I'll take another look at this later and see what I can see - not sure about what jumpers there were off the top of my head nor the state of the capacitor but I'll investigate.

[crt404]

The academy I used to work in had the Optiplex-745 which also had the external power pack. They are known for their unreliability. Even if the light on the power pack is green, disconnect the kettle lead, wait 30 seconds for everything to discharge (for good measure, unplug the lead to the machine as well) plug it all back in, and the machine should fire-up okay.

 

The real pain we used to have were our power-packs had been built into the academy's furniture and so to do this we would have to take furniture apart!

[twin--turbo]

I had an SX running my MythTV till it stoped posting. gave up on it and sold it.

 

Does it power on at all?

 

Rob

[kaphc]

No there's nothing power at all, no lights, not even a fan whirring or anything. I might be able to try swapping the power pack but the leads are all cable managed into a tray underneath the desks and so it's like a mass of spaghetti to untangle!