Hello,
I'm back to you with some new informations.
I did some measurements on my working O350 brick.
And i can safely assume that the DS1780 G7G5 is the one not working.
I confirmed by doing some continuity test on the dead one (G7G5 DS1780, Pin 16).
It also goes through the 1K resistor network array H1G5 (haven't check the others DS1780, but there is 2 others resistors arrays near H5G5).
I soon will pull the trigger (to continue the weblacky's bullet metaphor) on a 5 or 10 pcs order (just in case and it's a bit less expensive starting 10 Pcs), and i will keep you update on the repair process and the result.
I will preventively change all of them (maybe after changing G7G5 to confirm) anyway to be ready for the next 15 years (hopefully
).
On the subject on the different tensions i have some questions that haven't found any answer.
I have 6-7 threads to read about some similar subjects including weblacky's rabbit hole, so maybe some of those answers will be inside (sorry in advance if that's the case).
- So first the PSU output a 15V tension (15V BIAS) but i don't know what's its purpose and where is it measured ?
(There is no info in the Env. variables and the DS1780 has no 15V input, so maybe it's not monitored)
- *** There is some DC-DC conversion on the CPU node, so I assume there is also a DS1780 on it to monitor the voltage. Have you already disassembled the CPU node heat sink/metal duck ? Is there any DS1780 (haven't found any on the underside ***read NB at bottom) ?
- The CPU heatsinks seems to be riveted to the metal ducts and I am wandering if it's worth tearing down to check and maybe change the thermal paste ?
- I'm also asking myself why, over the years, no schematics have leaked. Also at some point most electronics products (i know it was really a thing in consumer Hi-Fi) had their schematics laid out in the manual or at least in a service manual. It was a great source of informations for diagnostics.
I also noticed a DS1780 on the 2U_PCI_Riser E9B0 and this one measure 1.8V on Pin 19 and 2.5V on pin 18.
So this one should/could/would be changed also preventively.
There is also an LTC3728 doing the DC to Dual DC (1.8V + 2.5V) conversion.
So far i have found (maybe for future reference):
G7G5 :
-Pin 17 : PCI 3.3V or 3.3V
-Pin 16 : PCI 5V
-Pin 15 : 12V #2 or 12V IO or IP59 12V
-Other ADC input pins 0V
H5G5 :
-Pin 17 : IP59 3.3V Aux or 3.3V Aux
-Pin 16 : PCI 5V Aux or 5V Aux
-Pin 15 : 12V #2 or 12V IO or IP59 12V
-Other ADC input pins 0V
N4K4 :
-Pin 15 : 12V #2 or 12V IO or IP59 12V
-Other ADC input pins 0V
E9B0 (2U_PCI_Riser):
-Pin 19 : 1.8V
-Pin 18 : PCI 2.5V
-Pin 17 : PCI 3.3V or 3.3V
-Pin 16 : PCI 5V Aux or 5V Aux
-Pin 15 : 12V #2 or 12V IO or IP59 12V
-Pin 14 : IDK, measured at 3.145V
Thank you all for your precious inputs and for reading my long and hopefully useful post.
I'll be waiting for the reception of the ICs and i hope I'll have some good news.
***NB :- I have found the DS1780 on the CPU node, it is located between the two 2.5V DC/DC conversion boards (VMEM & Bedrock) name : B3D3.
-Also a DS1780 can measure a sixth tension on pin 14
).