[SOLVED] p320 tiny won't display anything

[tinfoil3d]

Hi guys, anyone has p320 tiny around?
I bought one off local market, seller claims it to be in working condition, but it came with no ram and no CPU.
I didn't have core gen 6 or 7 so i bought i7-7700 from another seller who also claims CPU to work yet auctioned it off starting with 1 JPY, i won it for around 50 USD, and seller was selling CPUs like mine for a long time and has 100% feedback so i have no idea what to think of it now.
Symptoms TLDR: powers on, fans spin up a little bit then slow down for 3-4 seconds, then spin up again, and repeat, no video on any DP or even on analog VGA port that came with the system. I don't know if P320 is dead or CPU is dead. There are no audible alarms, i tried resetting cmos as per https://download.lenovo.com/pccbbs/thinkcentre_pdf/p320_sff_ug_en.pdf page 39, didn't change anything.
I don't know what CPU was in the system before, maybe I need to get the cheapest i3-6xxx and try powering it up with that? I don't know what to think and the guide is for SFF system not Tiny. Not sure if im resetting CMOS correctly.
Is there any other way to troubleshoot this issue other than buying yet another CPU i won't use other than for testing?

 

[tinfoil3d]

I did try resitting coin battery and that did lead to PC starting up as soon as PSU is plugged in(until that it only powered up when button was pressed). But this didn't produce any display output still.
RAM should be good, anyway, removing RAM completely produces the same result: fan spins, power LED on, heatsink is getting warm but no video output.
Oh yeah, it also powers on with Alt+P from a dedicated keyboard USB port if this helps at all.
I also tried another good PSU(initially used a 135W one that came with this computer), 200W one, same results.

 

[RolloZ170]

maybe I need to get the cheapest i3-6xxx and try powering it up with that?

maybe. or a G3900

is there any other way to troubleshoot this issue other than buying yet another CPU i won't use other than for testing?

sell the 7700 and you know if the CPU is good or not.
you will not have any good results with this 65W cpu in the P320 (cooling CPU & VRMs)
btw: power on with no display & further action is a well knows failure with the tiny's (but i don't know whats the issue is then)

 

[tinfoil3d]

@RolloZ170 thanks, G3900 isn't in the psref https://www.compuram.de/system/007507/lenovo_thinkstation_p320-tiny.pdf
However 7700 is listed as compatible, there is an all-copper heatsink for it, but im not sure if i'd need it, maybe it won't be used over 50%.
I'll try to resit CPU tomorrow but this is weird stuff. No beeps, tried the "speaker" unsoldered pins too, no beeps. AMI bios with power on but no beeps can also indicate a CPU or MB failure, i have no idea which one.

 

[RolloZ170]

thanks, G3900 isn't in the psref

ok i see its already a Q270 chipset, the BIOS supports 7th gen out of the box.
the g3900 is skylake-S and runs on every 1151(not v2) board, not on list because not sold with P320 by Lenovo.

 

[tinfoil3d]

Thanks, will try getting G3900, because the chassis was super cheap, got it for 30-35 bucks, no RAM, no CPU, with SSD caddy, cable, PSU and VESA mount.

 

[tinfoil3d]

Put in G3900 and it just started up so the i7-7700 CPU was dead.