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January 20, 2007, 2:58 am
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Looking for a Manual or at least front-panel pinout for Chaintech
pentium4 MoBo. Can't find the manual, the MoBo has no helpful
markings, and the Chaintech download site isn't working.
Should have written down the connections before I started transplant
into newer case. -Tx
Re: Chaintech MPM800-3 Manual
The download page gives this link, but attempts to transfer it
give "empty file". It would appear Chaintech has changed hands,
provides limited support in the form of driver files, but no
If you want to look for yourself, this is their alternate download.
ftp://ftp.chaintech.com.tw/ username=driver password=driver
There is nothing there for manuals. Only drivers of sorts.
I got the link to the FTP site from here:
Picture of motherboard. In the upper left hand corner, is what
looks like an "Intel-standard" 2x5 FP_AUDIO header.
This is the pinout for a 2x5:
MIC X X AGND
MICPWR X X +5VA (do not use - hard power source)
Line_out_R X X BLINE_OUT_R
No Connect X
Line_out_L X X BLINE_OUT_L
When not using FP_AUDIO, a jumper goes from Line_out_R to BLINE_OUT_R.
When not using FP_AUDIO, a jumper goes from Line_out_L to BLINE_OUT_L.
And you can see the two jumpers in the picture of the motherboard.
BLINE_OUT_L and BLINE_OUT_R go to the green Line_out jack on the
back of the motherboard (tip and ring of the 1/8" plug). The audio
signal comes from the AC'97 audio chip, on Line_out_L and Line_out_R.
If you use an "Intel Standard" computer case audio wiring, the front
panel headphone jack has four wires for Line_out_R, BLINE_OUT_R,
Line_out_L, and BLINE_OUT_L. The headphone jack implements "rear
speaker muting", by breaking the connection between Line_out_X
and BLINE_OUT_X. When you plug headphones to the front of the
computer, an "Intel jack" breaks the connection to the rear green
connector. That is why those four pins are present on the FP_AUDIO
header, to support muting.
Some computer cases do come with four wires, two are Ear_L and
two are Ear_R. The two Ear_L would go to Line_out_L and BLINE_OUT_L.
The two Ear_R would go to Line_out_R and BLINE_OUT_R. The four
wires are used, just so there is continuity to the rear jack.
That style of wiring doesn't support the muting function. The
rear speakers in this case, run all the time, whether headphones
are plugged in or not.
In terms of the actual jacks on the front panel, this is how they
connect to 1/8" jacks.
Microphone Tip, Ring, Sleeve = MIC, MICPWR, AGND
Headphones Tip, Ring, Sleeve = Line_out_L, Line_out_R, AGND
MIC is the mono microphone input. MICPWR is a weak source of power
for electret microphones (5V limited by 2K ohm resistor). On a
limited number of AC'97 CODECs, the microphone function can be
stereo, but most likely will be monophonic. When the microphone
is stereo, both MIC and MICPWR have separate bias sources on
them (the 5V with 2Kohm thing exists on both pins).
+5VA is intended to power a headphone amplified, but computer
cases don't seem to have those. Be careful with +5VA, as I
don't know if it is fuse protected or not. And the NC (No Connect)
pin is for keying, so you get things right-way-round.
That is my best guess on your wiring - hope it really is Intel