Foxconn H61MX does not have memory repair

Foxconn H61MX but memory replacement two small triode fault repair

Foxconn H61MX does not have memory repair

Foxconn H61MX but memory replacement two small triode fault repair.

Machine model: Foxconn H61MX

Fault phenomenon: power on horn long sound, but memory

Maintenance process: first, check the memory VCC, the main memory VCC 1.5V is normal, the memory benchmark 0.75V is normal, the memory SPD 3.3V is normal, the memory bus VCC 3.3V is normal, the memory reset 1.5V is normal, several common memory test points have been checked, the BIOS brush is invalid, check the two memory buses as usual.
Foxconn H61MX does not have memory repair
Foxconn H61MX does not have memory repair Figure 1.

After two smalltriodeAt both ends of PCH,VCC is 3.3V, which does not seem to be a problem.
Foxconn H61MX does not have memory repair
Foxconn H61MX does not have memory repair Figure 2.

Is the CPU BTB connector Open?On the diode value card slowly, a lot of pin bits, plus their own did not clear the definition of each pin bit.Therefore, when checking the drawings of Xinzhizao Soft, it is found that the network card is connected. The common phenomenon is that the components connected to the bus are damaged and the memory cannot be detected.It’s easy to connect the network card. After running the circuit, I found that there is no network card on the board.
Foxconn H61MX does not have memory repair

Foxconn H61MX does not have memory repair Figure 3.

Small triode broken before also encountered, but now both ends of VCC are very normal, but this board both ends have pull-up resistance, even if the transistor is broken,VCC measurement is normal.Look at the oscilloscope, both ends of the measurement can be caught, and both ends of the measurement are the same waveform, should be triode is good.

Now the CPU does not detect memory, check CPU BTB connector IO, etc.Finally, I went back to the two small triodes. I / O or some peripheral components were broken in the previous maintenance, because the memory could not be detected. Although the oscillograph measured that the small triode had waveform passing through, it was more complicated to change io for other components. Anyway, we had to take a try. It was convenient and quick to replace these two small triodes, and booting up was the direct way for troubleshooting and maintenance,Two small triodes model 7002.