Hi @mariodimonti ,

You may have a look on this thread regarding similar problem. Sometimes resetting components more than 1 time or even place your PC horizontally may bring your T3500 back to life. Worth to try!

thanks for your support - I had already tried all the hints in this forum - before I opened the thread.

I'm trying to understand the process.

Is this pre-bios routine and  the pb7 error a special feature or bug of DELL?

Apparently there is often this bug when exchanging a hardware component.

my interpretation of the pb7 error:
Run through Pre-Post > try to start the Bios > For unknown reasons Bios does not start and therefore not the actual POST, which can give me a detailed error message via beep code.
My port 80h card shows at the first start "nothing" and the second start the code "00". "00" means no bios start.

For me everything points to a defective bios.
Apparently there is no way to restore the bios. With some manufacturers there is this possibility already for over 20 years. At DEll it seems to be the case only since 2012.

bfn mario

Hi @mariodimonti ,

Sorry for your situation indeed. I know how it feel when you are excitingly expecting a better machine by hardware upgrade but then it blows up everything.

PB7 error often leaded by bad sitting of CPU or CPU Riser, or any other bad-contact between hardware that leads to BIOS loading failure. I'd say, Dell Precision is quite a sensitive series towards hardware changing, specially when we're talking about a workstation that 1st launched almost 10 years ago. I often recommend users to do a BIOS factory default reset before any critical hardware changing. It somehow helps in preventing this kind of fail-to-POST problem (although not always).

But of course it's not a design patent for Dell. Any brand happens. For example, I have a Lenovo Edge 92 with exactly the same fail-to-POST problem before. Same as what you did on your T3500, I did everything I could from resitting all hardware to even dismantle BIOS battery for days. Nothing help. Until one night after 3 months that I almost forgot this buddy and try to power it on again with no expectation. And then... it returns to life again! I cannot explain it other than miracle. Hopefully miracle comes to you as well, dude.

Thank you very much for your contribution - it comforts me - sometimes you doubt your own mind.

I also know such miracles.
I have used a hard disk as a paperweight for years because it was no longer addressable despite many attempts. In those years it had to suffer a lot because I was very careless with it. Now I wanted to dispose and connected it again for fun - it ran up without problems and the smart-test was ok.

bfn Mario

Translated with 

Please tell me how can i solve this pb7 problem