View Single Post
Old 10-10-2018, 02:54 AM   #23
Capt. Cap
Member
 
Join Date: Oct 2017
City & State: SF, CA
My Country: US of A
I'm a: Knowledge Seeker
Posts: 36
Default Re: Another HannsG HG281D

Logic board PM549DA3 M06 VER6.0 images attached

Q14 is a 9435GM P-channel enhancement-mode power MOSFET
Q15 is a 2N70002K N-channel enhancement mode MOSFET
Pins 1-3 are source, 4 is gate, 5-8 are drain

I poked around some more with the multimeter while I had the logic board completely detached for the photo session.

For Q14,
LVDS pins marked 1-3 on the logic board (and go to F400 on the TCON) go to this drain
drain to source is 558mV in diode mode
No pins are shorted to ground, though gate sometimes looks like a capacitor charging (resistance quickly rises to infinity over a second or two)

Q15
gate is grounded, source to drain is 577mV in diode mode on the multimeter

10.1kΩ between Q14 drain and source pins (1-3) of Q15
There's > 2MΩ resistance between the +12V supply line and all pins of Q14 and Q15

FB7 & FB8
No resistance across each of them
I get infinite resistance from each FB to source on Q14
FB7 and FB8 both have 509Ω resistance to both source on Q15 and ground

Q8 (obscured by C69 in the photo) is unpopulated


Is gate being grounded on Q15 normal?
Maybe the inductors feed Q15 which in turn feeds Q14?
Attached Images
File Type: jpg PM549DA3_M06_VER6_0_front-3000.jpg (1.86 MB, 4 views)
File Type: jpg PM549DA3_M06_VER6_0_back-3000.jpg (1.50 MB, 2 views)
Capt. Cap is offline   Reply With Quote