Question b450 tomahawk max, red vga light, no display, no post, faulty mobo?


Nov 23, 2013
So basically my mobo ''died'' 2 months ago. First it had red cpu light, no display, then i shut my pc down via PSU button, and since then it wouldnt boot or even give a single fan spin, it literally acted like it wasn't plugged in power. Then I rmaed it, and they were fixing it for 2 months, and called me that it is fixed now, it is working. I drove 90km for pc, paid diagnostic, even tho i told them what was wrong, and i came home plugged in everything and it seemed fine. Then all of sudden my pc shut down in middle of idle, it restarted and had red light on DRAM. Then i pulled out one stick of ram out of slot 4, and it booted normally. I put that stick right into slot 4, same error again, not post, red light on DRAM on mobo. Then i tested individually both rams into slot 2, it booted normally. I was doing that for half a day, and then all of sudden it worked with both rams in slot 2, and slot 4, like it should've. But once it booted it crashed, BSOD and no post again. I did memtest it got errors on teest 7, 128 of them, saying something like CPU : 6, which idk what it is. Next day i powered on pc, it booted normally, did memtest 3 times, 4/4 stages, and 0 errors found, no errors with ram. Pc worked fine entire day, i did benchmarks, did stresstest, everything worked fine. Before sleep i shut it down and thats it. Next day i woke up powered PC on, red light on VGA and no POST. I thought that my gpu died even tho it made no sense to me. I did cmos restart, did everything, still no post, red VGA light on mobo and nothing on screen.. I pulled out my gpu and put it in bottom PCIE slot, and it works fine... No errors, no red lights, nothing, works fine. I tried Putting it in top PCIE slot again, nothing, fans are spinning, LEDS are on, but no display, no post, and VGA light is on. I put it in bottom PCIE, works.. I called the shop where i bought mobo and cpu, and they are telling me that mobo is fine, and that it must be something with other components, and that they are 90% sure that it is CPU or RAM causing trouble, and not mobo. I wanna ask now, do you guys think that its CPU, or its repaired mobo, and i should tell them to give me brand new one. Because it doesnt make sense to me, that top PCIE slot is not working, and bottom one is, and day before slot 4 wasnt working on mobo and had no post, and now it works.. Thank you for help. Btw i did prime95 test for 30 min, and it had 0 errors aswell..

PC specs are: b450 tomahawk max
rtx 2060 oc 6gb
gskill trident z 16 gb
ryzen 7 3700x
corsair tx750 psu
Apr 23, 2022
I have this same problem, however I get a CPU debug light when i plug my 1060 6GB into PCI_E1. The gpu works when its in the lower slot. I want to guess that the PCI_E settings need to be changed somehow, to what I'm not sure.