Don't know If you already found my thread from July: MSI MS-5169 dead - blown MOSFET?

I ended up replacing the MOSFET and brought the board back to life. The thread contains instructions on how to measure the voltage. In case you need to make a similar repair, make sure to use a new CPU also. Mine was dead, it had a short that could have killed the newly replaced MOSFET right away.

You should also check that the MOSFET is not shorted. Measure resistance across the MOSFET(s), from pin3 to pin2(tab). Also Vcore can be measured without processor installed.

I just managed to destroy two socket 370 celeorons due to shorted transistor before I relized what's happening. It was 5V directly on CPU core. I really hope this is not the case with your MB.

ok thanks will report back in a few min , going to go do this now

fool wrote on 2020-11-22, 16:49:

You should also check that the MOSFET is not shorted. Measure resistance across the MOSFET(s), from pin3 to pin2(tab). Also Vcore can be measured without processor installed.

I just managed to destroy two socket 370 celeorons due to shorted transistor before I relized what's happening. It was 5V directly on CPU core. I really hope this is not the case with your MB.

ok so looking at the data sheet

i see on the mofet a drain and source.

I put my multi meter in diode mode

negative on the drain which is the middle pin and then to the right the souce which i put my positive probe
,
one measured 0.556v almost 0.6v
the other measured 0.192v which is concerning. Both mofets had high resistance nothing opened or shorted

is this the correct way to read it? under 0.3v is a bad mofet.

however i went on this site http://electronicsbeliever.com/how-to-know-if … t-is-defective/ and my mofets passed all the tests.

The only thing i noticed was 0.192v reading on one mofet messured at the drain and source

quite confused here ,seems like there is a crap load of tests for mofets

fool wrote on 2020-11-22, 16:49:

You should also check that the MOSFET is not shorted. Measure resistance across the MOSFET(s), from pin3 to pin2(tab). Also Vcore can be measured without processor installed.

I just managed to destroy two socket 370 celeorons due to shorted transistor before I relized what's happening. It was 5V directly on CPU core. I really hope this is not the case with your MB.

my processors are still alive after testing on a different mobo.

also my mofets look brand new not cracked or solder melted

no one has a clue huh

I had the very same issue with Gainward 5VPA with VIA MPV3. It did nothing. After changing FSB/multiplier/memory jumpers back and forth suddenly it just woke up. Those things can be tricky and there are about a million things to check. Maybe I would just remove all jumpers and re-install them according the manual starting from the clear CMOS jumper 😀 Be sure you have JV1 on dual voltage, MMX and K6-2 use dual supply. Does it beep without memory/video card? Have you tried different power supply?

It sounds like transistors are good. I would also measure AC and DC voltage levels from the load-side if there is a test point or capacitor can also be used. Ripple voltage should be very close to zero (couple of millivolts) and DC of course the level you have set. Multimeter is not ideal for measuring high freq ripple, but it will give you some hint if capacitors are failing. Remember ripple is supposed to be high between transistor and coil, so measure closer to capacitors.

I have MS-5169 v2.1 somewhere and it does not work with K6-2 greater than 500MHz. Nevertheless 233MMX should be fine of course. With K6-2 FSB can be set to 66MHz and multiplier to x2.0 -> processor translates it to x6.0 giving 6x66=400MHz for troubleshooting purposes.

fool wrote on 2020-11-25, 18:45:

I had the very same issue with Gainward 5VPA with VIA MPV3. It did nothing. After changing FSB/multiplier/memory jumpers back and forth suddenly it just woke up. Those things can be tricky and there are about a million things to check. Maybe I would just remove all jumpers and re-install them according the manual starting from the clear CMOS jumper 😀 Be sure you have JV1 on dual voltage, MMX and K6-2 use dual supply. Does it beep without memory/video card? Have you tried different power supply?

It sounds like transistors are good. I would also measure AC and DC voltage levels from the load-side if there is a test point or capacitor can also be used. Ripple voltage should be very close to zero (couple of millivolts) and DC of course the level you have set. Multimeter is not ideal for measuring high freq ripple, but it will give you some hint if capacitors are failing. Remember ripple is supposed to be high between transistor and coil, so measure closer to capacitors.

I have MS-5169 v2.1 somewhere and it does not work with K6-2 greater than 500MHz. Nevertheless 233MMX should be fine of course. With K6-2 FSB can be set to 66MHz and multiplier to x2.0 -> processor translates it to x6.0 giving 6x66=400MHz for troubleshooting purposes.

I looked at the manual for this mobo and see no JV1 header

Yep just verified in the manual

no JV1 Header by the ATX Connector on the mobo

I am pretty sure my jumpers were set correctly for a 233mhz mmx

You are right, checked the manual of 4.0. It turns out MSI has upgraded it in a way it no longer supports single voltage processors -> no-MMX Pentiums, Cyrix 6x86 or AMD K5.
OT: Actually what did they change to gain K6-III support...?

fool wrote on 2020-11-27, 15:44:

You are right, checked the manual of 4.0. It turns out MSI has upgraded it in a way it no longer supports single voltage processors -> no-MMX Pentiums, Cyrix 6x86 or AMD K5.
OT: Actually what did they change to gain K6-III support...?

what cpu works then?

Did you manage to make the board posting?
I'm asking because I have a hard time booting it too, although my version is 2.1 AL9.
I have a similar simptoms with Q1 mosfet above the processor near the ATX plug. The reading between the Drain and Source is about 045, and the Gate and Drain is 018. I can't change the state of the transistor by chargin it or drain it using my finger. The board remains silent, no POST signals, only FAN spins. I am testing it with a Pentium MMX166 (which I know it's working because I've tested it on another board), all jumpers are set accoring to the manual from the MSI site. I tried a 100Mhz and 133Mhz SDRams as well, still no luck.
Maybe I am missing something, my testing is wrong, because I am a newbie if it comes to mosfets?

I am pretty sure.its.the mosfet going to replace mine.

Yep, worth to try. Thanks for quick response.

I've replaced the mosfet and some capacitors nearby. Now the mobo works with intel mmx166 and 133 no mmx aswell. Gonna test other cpus later on. Still have minor tweaks to do tho.