b450 tomahawk max - dead

[Gobbla]

hello everyone
I got my hands on b450 tomahawk max - dead no power no post
There is no short or any other indication of fault - no spillage no burnt
I tried 750w power supply but still nothing - shorted correct pin but still no lights (they are some led at back and one small at front - test one)
I found someone selling bios chips - BIOS CHIP - MSI B450 TOMAHAWK / GAMING PLUS / PRO CARBON AC / B450-A PRO MAX - is it worth trying guys ?
thank you

[dicky96]

Re: b450 tomahawk max - dead

Not really, you need to test a lot of other things first - ask yourself this question - how can the CPU be executing (corrupted or otherwise) code from the BIOS if the board does not even power on? When you figure out how it can do that please let me know as I would be learning something which is always a good thing.

So
0. When you say there are no shorts - where did you check exactly?

1. Is there power on the pin headers to PS_ON switch and reset switch?

2. Is there standby power on any of the capacitors on the ICH (southbridge)and PCH (northbridge) substrate?

3. Are there shorts on any of the capacitors on the substrate of those chips?

4. is the CMOS battery good? How many volts do you see? Also measure the current drawn from the CMOS battery when the motherboard is not connected to the PSU - what is the reading?

5. Is the RTC crystal oscillating?

6. is there standby power on the SIO (Super IO chip)

That should be a good starting point. Post the results of those test. Then there are plenty more things to check before we get to the BIOS

[Gobbla]

Re: b450 tomahawk max - dead

What first came to my mind is that someone tried to flash board and brick it - I was told its just dead and all the other components have been tested - they got replacement and it did do the job

0. no shorts on caps on mosfets - board is very clean btw
1. will check that
2. will check if there is any voltage on caps
3. no shorts on caps but did not really look on chipsets
4. will check that
5. hmm that could be hard do I need oscyloscope ?
6. will have to find that chip and try when psu plugged in

Thank you for replaying that could push me one step forward I'm not a pro but I know something and willing to learn

And will try to post picture of motherboard tonight.

[SMDFlea]

Re: b450 tomahawk max - dead

The board has some debug LED`s .The bios you can get from the support site, no need to buy one,just program the existing bios chip, if you have a programmer .Do the other tests frirst though as suggested by dicky.

[mon2]

Re: b450 tomahawk max - dead

@dicky96, like how you started with 0 Digital designers at heart.

[dicky96]

Re: b450 tomahawk max - dead

@mon2 - if I told you I thought of tests 1-6 first... then threw 0 in as an afterthought, and quite simply I could not be arsed to renumber the other ones, would I lose some street cred in your opinion lol because in all honesty that's how it happened...... but I can accept in hindsight that it looked far better than it was intended

However I hereby reserve the right to retain the possibility of gaining more cred in future by doing so again more deliberately lol

Rich

[RJARRRPCGP]

Re: b450 tomahawk max - dead

Darn it, those motherboards are supposed to be solid, unlike many AM3-era motherboards!

[Gobbla]

Re: b450 tomahawk max - dead

Thank you all for replay

Will check more before weekend - voltages and more

Debug leds are dead :/ nothing at all

Yes I know they look solid but they are not top shelf - all they do is change logo at boot and sell as military / gamer board

[ChaosLegionnaire]

Re: b450 tomahawk max - dead

Darn it, those motherboards are supposed to be solid, unlike many AM3-era motherboards!

yes but that doesnt preclude the possibility of someone using a junk psu and killing the board! thats why getting a solid japcap psu is important also! especially if u want your stuff to last! gpu is usually first to go in this case and hard drive second. the ultra-low ripple from the japcap psu should make hard drives last longer but they are also packing too many bits per square inch into the platters that the data retention just becomes too "brittle" or "fragile" so to speak.

[Gobbla]

Re: b450 tomahawk max - dead

yes but that doesnt preclude the possibility of someone using a junk psu and killing the board! thats why getting a solid japcap psu is important also! especially if u want your stuff to last! gpu is usually first to go in this case and hard drive second. the ultra-low ripple from the japcap psu should make hard drives last longer but they are also packing too many bits per square inch into the platters that the data retention just becomes too "brittle" or "fragile" so to speak.

agree recently have seen build with some junk 450w psu - did not last long .. mid end gpu card + ryzen 5 + some rog board what a shame putting crap psu inside .... what is strange that did work for some time !!!

[piernov]

Re: b450 tomahawk max - dead

Note that PCH will read soft strap from SPI ROM before the CPU starts, sometimes if it fails it can power cycle with a very short pulse that's easy to miss if you don't have a very fast multimeter or oscilloscope, and you may think the board is stuck in S5 state.
Also it's rarely the case on desktops, but the Embedded Controller can have its firmware in the same SPI ROM as main BIOS, and if it cannot be read it would cause no power at all.