hi i bought a few old compaq small form factor deskpro en. two of them work but 5 won't power on. i took off the lids and can see a green led blinking. ive tried everything to get it to power up.held in the power switch. pressed the keyboard buttons, and cleared the cmos but still it stays off. its like its stuck in standby mode. do i need to somehow wake it via the on board network card? if so how can i do this? i'm very confused and despirate to get them going

i do not believe it is anything to do with waking it via the network card. If you have cleared the cmos and you cant get an image on screen when switch on (eg. white text on black screen or compaq logo) then it must be something to do with hardware. Have you checked the CMOS battery (silver coin bettery) is good? You are lucky you have working ones also of same model. What I would do is substitute parts between a good one and one that does not work to narrow down the fault - swap one item at a time eg. ram , cpu , power supply etc. I once bought 5 identical IBM net vista PCS, 2 worked, three did not, by process of swapping parts I found that the 3 that did not work all had faulty motherboards.

hi good idea i have swapped the power supply of the working one into the faulty ones and they now work so it is the power supplies stuck on what seems standby. its so strange. does anyone know how i can reset the power supply units?

The power supplies are probably defective, they cannot be reset. You can obtain an inexpensive power supply tester to check them out. http://www.google.com/products?q=po... On second thought, those testers might not work for 'some' Compaq power supplies. Compaq has manufactured 'non-standard' supplies in the past.

i agree that the power supplies are faulty (assuming they are set to correct voltage-if they are the type that has a small sliding switch next to where the mains power cable goes in). An electronics person might be able to repair them but probably uneconomic to pay for that. I would think these power supplies are specific to that compaq model and can not be swapped with cheap generic ones - that makes replacement more difficult, and you cant move it all to another casing that will take a generic power supply as the motherboard will not be a standard type.

You might look for a series of pins and small black jumpers set on these pins ,it is a sequence that controlls this,consult manufacturers settings online!!

It is really not worth the cost of replacing the power supplies in these units. They are definitely proprietary. ie, generic power supplies will not fit. New replacements from HP (if available) would cost way more than the value of the rest of the box, and because they are proprietary, you will be lucky to find any working used PSUs. Either cut your losses and sell off the spare non-working boxes or keep them for spare parts and then put some time & effort into tracking down working powersupplies. I used to have a signature but it disappeared and I just couldn't be bothered writing another so please feel free to ingore this.