MP3Car.com - View Single Post - Fix for M2-ATX and Jetway!

Kai · 02-27-2007, 12:57 PM

Quote: Originally Posted by andrewb

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.

Problem explained:

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 does this translate to in visible terms to the computer user? As in motherboard turns and does this, while that doesn't do that.

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
LED on
cpu fan goes on
BEEP
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?

02-27-2007, 12:57 PM	#10
Kai Newbie Join Date: Aug 2006 Location: Lakewood, PA Posts: 13	Quote: Originally Posted by andrewb 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. Problem explained: 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 does this translate to in visible terms to the computer user? As in motherboard turns and does this, while that doesn't do that. 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 LED on cpu fan goes on BEEP 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?