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 ?
-
-
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.
peace.We don't have a great war in our generation, or a great depression, but we do, we have a great war of the spirit. We have a great revolution against the culture. The great depression is our lives. We have a spiritual depression. -
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 ---
If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
Please do not post inline and offsite as they slow down the loading of pages.
--- end sig file ---Comment
-
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
-
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)
Do some lower voltage mosfets fail like this?The strong-minded rise to the challenge of their goals,the weak-minded BECOME HATERS
Comment
-
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 -
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 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... -
Hello guys,
I have a shorted MOSFET K8A60DA with the following characteristics:
Type Designator: TK8A60DA
Marking Code: K8A60DA
Type of Transistor: MOSFET
Type of Control Channel: N -Channel
Maximum Power Dissipation (Pd): 45 W
Maximum Drain-Source Voltage |Vds|: 600 V
Maximum Gate-Source Voltage |Vgs|: 30 V
Maximum Gate-Threshold Voltage |Vgs(th)|: 4 V
Maximum Drain Current |Id|: 7.5 A
Maximum Junction Temperature (Tj): 150 °C
Total Gate Charge (Qg): 20 nC
Rise Time (tr): 25 nS
Drain-Source... -
Hello Everyone!
To start with, I am basically a noob when it comes to component level repairs. I identify myself at a stage where I am able to recognize some SMD components by shape, size and color. I know the very basics of testing the voltage by hooking the multi-meter probes and that's it.
Keeping that in mind, I will try to explain my situation in best possible way --
I own a 5 year old HP Pavillion G6 2288CA, a laptop known for its overheating.
I have used the machine lots in the past and sometimes left it on for days continuously.
...
Comment