Please help ID component

[crossride]

While installing Coolermaster Hyper 6 cooler on EPoX 8KDA3J (AMD Athlon
64, Socket 754) motherboard I broke a component which interfered with
cooler support frame.

This much I know about it.
Marking: WW1 / 46 (WW1 along the longer side and 46 rotated 90 degrees,
most likely 46 is a lot number)
Package: SOT23-3
ID on board: D39 (also D6 is same)
Location: Between CPU and ATX 20-pin connector)
Connections: Lead 3 goes to ATX 20-pin connector lead 8 (PWR-OK, aka
POWER GOOD), lead 2 sinks into any of the middle layers, lead 1 can be
followed on the picture at
http://velo.clubbers.ee/~erikr/D39/P1010002.JPG.

Measured resistance on leads of the another, non-broken one near the
CLEAR CMOS jumpers (position D6), any combinations between leads gave
readings of 600K or more up to infinity. Measurements done with Fluke 73
multimeter.
No lead connected with ground.

Have been searching on the net for a week but still no luck.
Based on electrical measurements cannot be a diode, transistors are
marked with Q on schematics, colleagues have suggested Zeners, field
transistors, JFETs, voltage supervisors.

WWx markings seem to be exceptionally rare, only real match with marking
is
http://www.smd.ru/files/upload/1245/ru/bat54.pdf
,see p2, marking section.
Near matches are http://www.marsport.demon.co.uk/smd/smdw.htm.

E-mail to EPoX support has given no reply.

Could anybody help to figure out the component, either original or if
knowing exact purpose of it, suggest a replacement.
I'd rather like to save the board that cost me 100 Euros than throw it
away.

Thanks in advance.

 

[paul405]

Sounds like a diode to me !!
maybe equivalent to an in4006 ?

good luck
de Paul

 

[legg]

While installing Coolermaster Hyper 6 cooler on EPoX 8KDA3J (AMD Athlon
64, Socket 754) motherboard I broke a component which interfered with
cooler support frame.

This much I know about it.
Marking: WW1 / 46 (WW1 along the longer side and 46 rotated 90 degrees,
most likely 46 is a lot number)
Package: SOT23-3
ID on board: D39 (also D6 is same)
Location: Between CPU and ATX 20-pin connector)
Connections: Lead 3 goes to ATX 20-pin connector lead 8 (PWR-OK, aka
POWER GOOD), lead 2 sinks into any of the middle layers, lead 1 can be
followed on the picture at
http://velo.clubbers.ee/~erikr/D39/P1010002.JPG.

Measured resistance on leads of the another, non-broken one near the
CLEAR CMOS jumpers (position D6), any combinations between leads gave
readings of 600K or more up to infinity. Measurements done with Fluke 73
multimeter.
No lead connected with ground.

Have been searching on the net for a week but still no luck.
Based on electrical measurements cannot be a diode, transistors are
marked with Q on schematics, colleagues have suggested Zeners, field
transistors, JFETs, voltage supervisors.

WWx markings seem to be exceptionally rare, only real match with marking
is
http://www.smd.ru/files/upload/1245/ru/bat54.pdf
,see p2, marking section.
Near matches are http://www.marsport.demon.co.uk/smd/smdw.htm.

Could it be WW4?

WW3 CMPZDA2V4 CSC SOT23 dual ca zener 350mW 2.4V
WW4 CMPZDA2V7 CSC SOT23 dual ca zener 350mW 2.7V
WW5 CMPZDA3V0 CSC SOT23 dual ca zener 350mW 3.0V
WW6 CMPZDA3V3 CSC SOT23 dual ca zener 350mW 3.3V
WW7 CMPZDA3V6 CSC SOT23 dual ca zener 350mW 3.6V
WW8 CMPZDA3V9 CSC SOT23 dual ca zener 350mW 3.9V
WW9 CMPZDA4V3 CSC SOT23 dual ca zener 350mW 4.3V

This should give diode-type measurements with pos lead pin 3 (single
lead side) neg lead on either pin 1 or 2 (double lead side). Pin 3
would likely be grounded.

Unlikely that any configuration (except dual or single bipolar tvs)
would give high z on all leads.

RL

 

[[email protected]]

the results of onboard diode function test for the known good one are
the following:

pos-neg
1-2->OL
1-3->286 ohm
2-3->beep

neg-pos
1-2->beep
1-3->OL
2-3->OL

my skills level is too low to figure the diode configuration out of
this.

 

[[email protected]]

the results of onboard diode function test for the known good one are
the following:

pos-neg
1-2->OL
1-3->286 ohm
2-3->beep

neg-pos
1-2->beep
1-3->OL
2-3->OL

my skills level is too low to figure the diode configuration out of
this.

 

[legg]

the results of onboard diode function test for the known good one are
the following:

pos-neg
1-2->OL
1-3->286 ohm
2-3->beep

neg-pos
1-2->beep
1-3->OL
2-3->OL

my skills level is too low to figure the diode configuration out of
this.

I'd repeat this with (at least) pins 1 and 2 (two on same side)
desoldered on the known-good part.

I'm not sure what your meter does - in diode test you can usually
count on a fixed current, with the display reading the resulting
voltage drop in mv, or an over-range (> xmV) indication.

You don't care if it beeps; just read the display.

If a beep were intended to indicate a voltage drop lower
than y mV (ie a short), reversal of polarity shouldn't produce
conflicting results in an unpowered circuit for simple internal
configurations. Desoldering will give unambiguous results, regardless.

For a dual 2V7 zener, labelled WW4, with pin 3 common anode, readings
should be:

pos neg
3-1 200 to 600mV
3-2 200 to 600mV
2-1 OL

neg pos
3-1 OL
3-2 OL
2-1 OL

RL

 

[[email protected]]

OK, here are the results of off-circuit diode function measurements
for the known good one.
done with a cheapo Mastech M-830B tester

component leads 1 and 2 on the double lead side, 1 left and 2 right, 3
on the other, single lead side. (Philips style of marking)

pos-neg
1-2 -> OL
1-3 -> 200
2-3 -> 200

neg-pos
1-2 -> OL
1-3 -> OL
2-3 -> OL

 

[[email protected]]

OK, here are the results of off-circuit diode function measurements
for the known good one.
done with a cheapo Mastech M-830B tester

component leads 1 and 2 on the double lead side, 1 left and 2 right, 3
on the other, single lead side. (Philips style of marking)

pos-neg
1-2 -> OL
1-3 -> 200
2-3 -> 200
neg-pos
1-2 -> OL
1-3 -> OL
2-3 -> OL

any ideas based on this?

 

[legg]

OK, here are the results of off-circuit diode function measurements
for the known good one.
done with a cheapo Mastech M-830B tester

component leads 1 and 2 on the double lead side, 1 left and 2 right, 3
on the other, single lead side. (Philips style of marking)

pos-neg
1-2 -> OL
1-3 -> 200
2-3 -> 200
neg-pos
1-2 -> OL
1-3 -> OL
2-3 -> OL

any ideas based on this?

Congratulations. You've ot a WW4. ie CMPZDA2V7, dual 2V7 zener.

http://www.centralsemi.com/pdf/CMPZDA3V6-3V.PDF

RL

 

[legg]

OK, here are the results of off-circuit diode function measurements
for the known good one.
done with a cheapo Mastech M-830B tester

component leads 1 and 2 on the double lead side, 1 left and 2 right, 3
on the other, single lead side. (Philips style of marking)

pos-neg
1-2 -> OL
1-3 -> 200
2-3 -> 200
neg-pos
1-2 -> OL
1-3 -> OL
2-3 -> OL

any ideas based on this?

The reason your results are backwards is probably because your meter
polarity in diode test mode doesn't correspond to the lead colours.
This is strange to see in anything other than old analog meters.

You should definitely only see conduction when pin 3 is positive.

You are testing the zeners in forward conduction, not reverse
breakdown, using the common anode at pin 3.

RL