Need Help Idnetifying a Component

[ShortCircuited]

ZDW 38 SOT23. Can't seem to find the pdf for specs

[budm]

Re: Need Help Idnetifying a Component

May be this one: ZD (W = China)
https://cdn.badcaps-static.com/pdfs/...91a6652c2a.pdf
Test it to see if it shows as PNP transistor or not.

[ShortCircuited]

Re: Need Help Idnetifying a Component

Thanks for the reply... The terminals sharing the same side are dead short.

[budm]

Re: Need Help Idnetifying a Component

Can we see the pictures of the board so we may be able to figure out the function of this device?

[ShortCircuited]

Re: Need Help Idnetifying a Component

On a corsair cx600 powersupply-see arrow (Q10): https://postimg.cc/qgxkNV0D

[ShortCircuited]

Re: Need Help Idnetifying a Component

Also found 2n4125...but the package and SMD ID book are both wrong. PBSS5350T makes sense but the voltage on the primary side can reach around 350v dc What does the 38 suggest on it...anyone know?

The two terminals sharing the same side are being provided with .46v and the top pen 0v by the pcb. The main cap is charging to 168vdc

[R_J]

Re: Need Help Idnetifying a Component

The 38 is a date code, just because you can get 350v on the primary side does'nt mean that potential is applied to this transistor. The transistor could be used in the feedback circuit or even used as a switch to control whatever is connected to it's collector.

[budm]

Re: Need Help Idnetifying a Component

You can trace out the Collector pin to see if it is connected through other component that ending up connected to the circuit ground or positive power supply then you can tell if it is NPN or PNP Transistor; same tracing for the Emitter pin.

[ShortCircuited]

Re: Need Help Idnetifying a Component

The 38 is a date code, just because you can get 350v on the primary side does'nt mean that potential is applied to this transistor. The transistor could be used in the feedback circuit or even used as a switch to control whatever is connected to it's collector.

ZD are the only letters designating this component? W appears to indicate country of manufacture.

[redwire]

Re: Need Help Idnetifying a Component

It could be for low side mosfet gate drive, as the turn off transistor.
SMT marking ZDW PBSS5350T PNP 50V 2A(!) low Vce sat. BJT. ZD w-china, 38 as lot/date code.

[OniJon]

Re: Need Help Idnetifying a Component

I'll use the same thread for this question

[budm]

Re: Need Help Idnetifying a Component

Red rectangular = MICA capacitor
Three PBA 3002/6 = 75 Ohms resistors (marked as 2 = 75 Ohms) arrays, you can check the resistance.
Four PBRxxxc = Resistor array/network
Two Black disc = may be Thermistor, check the resistance when it is cold and when it is heated up with hair dryer.

[ShortCircuited]

Re: Need Help Idnetifying a Component

It could be for low side mosfet gate drive, as the turn off transistor.
SMT marking ZDW PBSS5350T PNP 50V 2A(!) low Vce sat. BJT. ZD w-china, 38 as lot/date code.

The primary side is not boosting so I dot think the gates are switching. No signs of life...not even stand-by. I have 0 resistance when I probe the PCB G and S traces. Unfortunately, I do not have the knowledge to trace the circuits and determine, but I do have the experience to NOT touch anything even when unplugged and not drained lol. I am thinking 50v PNP..slap one on and wait for smoke.

Nearly everything I probe on primary side is 168vdc

[budm]

Re: Need Help Idnetifying a Component

What did you use for Ground ref for your meter probe when you measure Voltage on the hot side?

[OniJon]

Re: Need Help Idnetifying a Component

Red rectangular = MICA capacitor
Three PBA 3002/6 = 75 Ohms resistors (marked as 2 = 75 Ohms) arrays, you can check the resistance.
Four PBRxxxc = Resistor array/network
Two Black disc = may be Thermistor, check the resistance when it is cold and when it is heated up with hair dryer.

Resistor networks/arrays I was aware but had to check, thanks. How do I know mica's capacitance/voltage values because my esr meter goes only down to 1uf reliably? I tried to google the text on top of them with no results.
101 should be 100pf but voltage?

[redwire]

Re: Need Help Idnetifying a Component

In OP's CX600 pic I see fractured soldering joints to a through-hole capacitor (at ZD2 pads) that connects to Q10. Did you fix that? Is the +5VSB alive?

OMG this is full of CapXon. The little daughter board uses PFC controller CM6800.

some CX600 pc board pics:
https://www.techpowerup.com/review/c...-cx600m/4.html

[budm]

Re: Need Help Idnetifying a Component

Resistor networks/arrays I was aware but had to check, thanks. How do I know mica's capacitance/voltage values because my esr meter goes only down to 1uf reliably? I tried to google the text on top of them with no results.
101 should be 100pf but voltage?

MICA caps are low capacitance cap (pF typ.), just check the capacitance with cap meter, you do not use ESR meter on MICA or ceramic cap.
https://technifest.com/technical-doc...pacitor-codes/

[ShortCircuited]

Re: Need Help Idnetifying a Component

What did you use for Ground ref for your meter probe when you measure Voltage on the hot side?

Heatsink and neg terminal of main cap as ground*....both provide same result...Tested again and getting .015vdc* today...maybe the weather.

*EDIT: retest gets .41vdc

[ShortCircuited]

Re: Need Help Idnetifying a Component

In OP's CX600 pic I see fractured soldering joints to a through-hole capacitor (at ZD2 pads) that connects to Q10. Did you fix that? Is the +5VSB alive?

It must be the image that makes it look cracked at ZD2, no caps near it. SB is not alive.

[redwire]

Re: Need Help Idnetifying a Component

Check whatever part goes to these two bad joints, and a third could use a touchup.
I think it's a CapXon on the other side.