richb99 Â Â 10 #1 Posted April 23, 2017 My old HP Compaq dc7900 SFF was working perfectly but now won't switch on. Tried different socket and power lead but still dead. Tested switch on front and that works O.K. so want to test PSU but internet says to disconnect all leads from PSU and bridge between pins 15 and 16 on the 24 pin connector. Elsewhere on the net it says doing this with no load could damage the PSU and suggests keeping the HDD and motherboard connected is the way to go. Advice would be appreciated as I am using an even older Dell running XP with all fingers crossed, making typing difficult. Share this post Link to post Share on other sites Share this content via...
richie3709 Â Â 10 #2 Posted April 23, 2017 http://www.hp.com/ctg/Manual/c01549447.pdf here is the manual if its any good to you Share this post Link to post Share on other sites Share this content via...
richb99 Â Â 10 #3 Posted April 23, 2017 Thanks for that, but far too technical for me as I am a silver (grey) surfer. I was looking to test the PSU and either replace it, or by-pass the power on signal by inserting a switch between pins 15 and 16. Share this post Link to post Share on other sites Share this content via...
altus   540 #4 Posted April 23, 2017 You could try the power supply in your Dell with the Compaq motherboard but beware - Dell used non-standard power supply connectors for a while. Read this before attempting anything: Dell proprietary (non-standard) ATX design.  If you're unsure of the compatibility of the Dell power supply, your best bet is to find someone with a spare power supply you could borrow. Share this post Link to post Share on other sites Share this content via...
Mikes10   10 #5 Posted April 23, 2017 What you want is a) local computer shop who is willing to test you computer PSU for free  or  b) one of these or similar ( or someone who is willing to loan you one ):  http://www.maplin.co.uk/p/lcd-atx-pc-power-supply-tester-a48gf Share this post Link to post Share on other sites Share this content via...
richb99 Â Â 10 #6 Posted April 27, 2017 Thanks for replies. Connected pins 15 and 16 with paperclip and tried with PSU connected up inside PC, and disconnected ouside PC and the fan in the PSU is not turning so assume PSU is dead and have ordered a replacement. Share this post Link to post Share on other sites Share this content via...