HP ProLiant ML110 G7 nie przechodzi POST

Hello!

- Measure the resistances to ground on pins A10, B1, B10 of slot PCIe2 x16.
- Set your multimeter to the diode test mode and measure the voltage drops to ground on pins A11, A13, A14, A16, A17, A21, A22, A25, A26, A29, A30, A35, A36, A39, A40, A43, A44, A47, A48, A52, A53, A56, A57, A60, A61, A64, A65, A68, A69, A72, A73, A76, A77, A80, A81, B5, B6, B11 of slot PCIe2 x16 with the CPU connected to the board.

PCIe slot pin count (top view):

matrixmm napisał(a):Z historii płyty mam informację, że ktoś wkładał kontroler w gniazdo PCIe na włączonej płycie.

Do you have an information which PCIe slot exactly was it? Was it the PCIe x16 or one of the small ones x8/x4 slots?

matrixmm napisał(a):B10 - 97R

This resistance seems a bit low to me.
Measure the resistances to ground on all coils.

matrixmm napisał(a):Przeprowadziłem jeszcze kilka pomiarów. Wlutowałem wszystko ponownie i grzeją się rezystory R862 i R868 a nie tranzystory jak pisałem wcześnuiej. Oba rezystory połączone są z drenem Q70. Jak zdejmę Q69 i Q70 to się nie grzeją ale płyta dalej nie przechodzi post.
Narysowałem kawałek układu jak to jest połączone.
[ Obrazek ]

This circuit is so-called "Discharger".
So when the board is turned on and the output voltage of the U111 converter is present and correct the signal on pin 8 of this chip (PGood) is at high state, the "Discharger" circuit is not in function - transistor Q69 is opened and consequently the gate of Q70 is "pulled" to the ground, so the transistor Q70 is closed and consequently the resistors R862, R868 are not in function.

This circuit does its job when we turn the board off - the "Vin" power rail is cut off, but the filter capacitors on this power rail stays charged. At the same time the converter U111 receives a low state (disable) signal on pin 14, so this controller turns off and it's output voltage starts to fall and consequently the PGood signal is pulled to the low state by chip U111. Consequently the transistor Q69 closes and the transistor Q70 opens (the gate of Q70 is "pulled up" to the high state via the resistor R861). When this happens the capacitors on the "Vin" power rail are discharged through the low resistance of resistors R862, R868 (the parallel connection of resistors R862 and R868 amounts 10Ω).

In your case the voltage on the "Vin" power rail is present, but the converter U111 is most likely disabled for some reason (the voltage to ground on pin 14 of this chip is most likely 0V) and consequently the PGood pin of this chip is also pulled low, so the "Discharger" circuit is activated and hence the resistors R862, R868 heats up.

So, measure the voltage to ground on pin 14 of chip U111. If there is 0V, the issue is not related to the chip U111 or "Discharger" circuit.