Intermittent no-POST Dell Demension C521

[Shylerbrew]

System is a Dell Dimension C521 - Svc. Tag 4q1X6C1. BIOS vers. 1.1.2 (11/08/06.) Processor is an AMD Athlon 64 3200+ clocked at 2.0 Ghz, Bus 1000 Mhz., L2 Cache 512 Kb. Memory 512 MB 533 Mhz Single Channel DDR2 SDRAM. OS is XP Media Center SP2. with 512 mb memory. System has all SATA connections. PCI slot1 contains a VGA display card, slot3 a modem card.
System frequently but intermittently fails during pre-POST. Startup will sometimes appear to check for HDD and go no further, leaving the start button a steady amber. Other times there appears to be no check of HDD before it stops, the start button again is steady amber. Sometimes the system starts as normal. Have checked power supply voltages, all OK. Checked PWS function by stripping down board and re-adding all cards and drives drives one at a time. System indicated no problems with each addition and started once HDD was re-added. The next boot it resumed the intermittent no-POSTs. Suspected bad SATA cables on HHD so replaced/exchanged with no change in symptoms. Have reseated all connections. System will start w/o issue once POST is successful and runs with out any problems.
I have not worked on any C521s and wondered if anyone with experience with one of these systems knows of any problems with BIOS, MoBos, etc., that could be causing the no-post situation. Dell's trouble shooting screens do not appear to address this situation.
Thanks.

 

[Shylerbrew]

Receiving not even one reply on this post leaves me with the feeling that no one anywhere has ever worked on a 521C, so that makes me the expert, huh?
Anyway, I ended up trying another (new) power supply and this turned out to be the solution. Apparently, the old one was not producing a consistent 12v at start up when under load, even though it did test out that way on the meter when running solo. Being that this is a Dell (proprietary) with a narrow frame to boot, I had to order a specific replacement for the 521C. Fortunately, ebay had several to choose from considerably less expensive than Dell.

 

[ACTI]

Sorry to hear no one was available to help earlier. Glad you figured it out though!