So i should replace my jetway board instead of my m2-atx, because im having boot problems?
Looks like I was able to nail a problem with all the Jetway MotherBoards firing up with M2-ATX and possibly other types of PSUs, especiually at low temps.
When a PSU starts up, some rails tend to 'overshoot', which is OK, if the PSU is designed well and if the overshoot is no greater that 5% on a specific rail.
Looks like the Jetway boards are really fussy on the 12V rail, during the startup sequence. If voltage goes over 12.5V at startup (BTW, within the ATX spec), the boards will fail to post, ESPECIALLY at low temperatures. Please note that this problem happened on only 5% of their motherboards, the rest work ok! (but enough to give us a huge headache)
While trying to find a fix to this problem I realized that this is a Jetway M/B specific problem. As we also distribute Jetway Morherbords, I called Jetway support. To my amazement, Jetway/Taiwan fixed the problem in less than 3 days! (Try this with VIA, hehe).
Voila, now all Jetway motherboards can now 'overshoot' the 12V rail and guess what... You can take the 12V rail up to 14.5V now. (do not try this at home).
What is also very impressive, is that we tested the Jetway M/B at -40Celsius and the M/B started every single time. We used a Half-Cube temperature test chamber, -40C is the max that this chamber can produce.
Starting Jan-15-2007, all Jetway motherbords will include this fix.
so what does changing C35 do then????? does it stop it from "overshooting"??
good to know what the problem is tho!
I have the same problem with the jetway 1.5 and m2 psu. I bought mine from cartft.com few weeks back. If I send mine back to them and explain to them about the fix how will I know the new motherboard they send me wil have the fix on it?
How do I know if I have a revised version or not? I bought three boards within the last month(dec 2006). I have these boot issues and now one of my boards don't even boot up bios. Please respond back with anything you know.
specs: m2-atx and 512 ram on jetway c7 board.
I'm about to order a Jetway M/B and M2-ATX. How can I know if the MB is the new revision? What should i ask the supplier? (I want to ask him if it's the new revision before ordering it)
I have a Jetway low power and am wondering if that is the exact problem I'm having or not. The problem seems to have surfaced with freezing temperatures. It was fine before.
Motherboard will power-up
cpu fan goes on
keyboard light goes on, then goes off....no keyboard power
vga screen does nothing....no vga power
motherboard continues to run LED and fan
USB CD-rom also appears to have power
Same exact thing or no?