I have 4 k3294 mos fets that test the same . Using an anolog meter on the 10k scale . with the neg probe on the source and pos on the drain. When I place my finger between the gate and the source the meter swicthes to a low reading which is typical but when I remove my finger the meter switches back to a low reading . Does mean that the device is bad ?
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Re: testing mosfet
the way i do that test is
put the DM into diode test and the pos to the drain and the neg to the source and should read open condition then i move the pos to the gate for an instant and the put it back to the drain without removing the neg from the source and the it should give some continuety and the if having that set up i touch the gate it should go back to open circuit. then do first steps again but instead of touching i switch the tips the red to the source and the black to the gate and then back as they were and it should go back to none. if that stuff gives the results mentioned then for me the mosfet is all good.
maybe im all wrong but thats how i do it. hope it helps.
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Re: testing mosfet
I test it this way. Set multimeter on ohms. Measure resistance "in circuit" between S-G, G-D, S-D. Any reading less than 30 ohms suggests it is shorted. If under 30 ohms, remove and retest out of circuit.--- begin sig file ---
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Re: testing mosfet
You mean it remains low? That might just be residual charge on the gate.but when I remove my finger the meter switches back to a low readingComment
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Re: testing mosfet
I have a question about a MOSFET FQPF 27P06 (60V P-Channel) I just tested with two different Fluke meters.
Fluke 1 showed:
On = .2 ohms, Off = 336K A little low for off state??
Fluke 2 showed:
On = 886K , Off= 886K No change.
Is this acceptable? (at least for the first fluke test)
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I tried to use this method:
Testing an N-channel MOSFET:
Step 1: Discharge the Gate (turn off the MOSFET)
Place the black probe (COM) on the Source (S) and the red probe on the Drain (D). The multimeter should show no continuity (high resistance or "OL" – open line).
Then, touch the black probe to the Source (S) and the red probe to the Gate (G). This discharges any stored charge in the Gate, turning the MOSFET off.
Step 2: Charge the Gate (turn on the MOSFET)
Now, place the red probe on the Gate (G) and the black probe on the...09-27-2024, 03:31 AM -
This is an lcd display used on ebikes.
long story short, there was condensation inside the unit.
I opened it and thoroughly cleaned the pcb with isopryl.
The board had no visible corosion.
It powered on fine and was tested for an hour or so.
However when connected to the bike,,it did not power on at all.
I took it home and reopened it to take a look. There are no shorts based on MY testing.
However,,when I probe the transistor and the mosfet gate in diode mode or contuinity mode, (one probe on transistor collector and one probe on mosfet gate}the unit...09-16-2025, 12:56 PM -
I'm working on a HP Pavilion Laptop Model 15-eh1508sa that is missing 19v. I've looked at the schematics and want to know what conditions the ISL9238C checks before it enables the gate for MOSFETs PQ8200 and PQ8201,
I havent found any shorts on the board.
I get 19v at +PRWSRC but around 1.7v at the Drain of PQ8201(+vin)
On Page 82 of the attachment. Link to schematic - https://www.badcaps.net/forum/troubl...ilion-laptop-p... -
I have a Razer laptop (RZ09 MB# CH570_MB_NT) that has a shorted mosfet marked BND M03 E067 that I'm unable to find anywhere online. Does anyone either know what the part number is for this mosfet or have a schematic I can find it in?
Backstory on the whole thing the laptop was plugged into a lamp at a hotel. The lamp got unplugged while it was charging and now the system won't power on anymore. I found the caps around this mosfet shorted and when I injected voltage into the caps the mosfet got hot and my bench psu was pulling 5A. Pretty sure this is all that's wrong with the laptop... -
I am testing an NPD603AL (N-Channel Logic Level Enhancement Mode Field Effect Transformer) from an old Comapq Proliant 1500 CPU daughterboard. Symptoms are no post / no video, with only the psu / blackplane / cpu daughterboard and CPU in place.
First question: This is not explicitly listed in the datasheet title as a MOSFET, however in the description it states it uses D-MOS technology. I assume this means it's just a MOSFET, and the "logic level" means it only needs 5v gate-source charge instead of 10v. Is that correct?
I am testing this because...
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