1. Home
  2. General Electronics
  3. Please help ID component

Please help ID component

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

formatting link

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

formatting link
,see p2, marking section. Near matches are
formatting link

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.

Reply to
crossride
Loading thread data ...

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

good luck de Paul

Reply to
paul405

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

Reply to
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.

Reply to
crossride

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.

Reply to
crossride

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

Reply to
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
Reply to
crossride

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?

Reply to
crossride

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

formatting link

RL

Reply to
legg

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

Reply to
legg

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.