aaronkatrini
Member
Last Activity: 06-08-2025, 01:55 PM
Joined: 03-06-2023
Location: Rome
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Worked like a charm, I can't thank you enough!... -
DELL Nvidia GTX 750Ti Mosfet goes short after a few minutes
Hi all,
I have recently picked up this Dell OEM Nvidia GTX 750Ti 2GB Video card. Its an old card I know but still wanted to get it working if possible. The problem is the following:
- Put the card in my testing motherboard and start running Heaven benchmark
- Benchmarks seems to run smoothly up until half way then the motherboard completely shuts off immediately
- Try to start it again and I get a slight move from the PSU fan - a clear short
- A little troubleshooting later I find one shorted Mosfet - Replace them both - short is gone
- Put the... -
Hi,
[USER="527845"]Loulou31[/USER] it doesn't have to be super accurate, its for hobby work, so I guess 1% should be fine. Thanks
[USER="15329"]stj[/USER] thank you for the recommendation, I checked briefly and seems to tick all the features I'm looking for and has reasonable price, will check out some reviews in the upcoming days. ThanksLoulou31...
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Recommend a decent Multimeter on the cheap
Hi all,
I was looking to upgrade my main multimeter (Asita MD591) with something that has more features. I'll use it mostly for board diagnostic and diy repairs. I've been eyeing out many of those multi-function ones from Aliexpress but can't seem to make my mind up. Here are the features that I'm looking after:
- Autorange
- DC volts up to 30V
- Accurate Resistance
- Diode test (Beep mode)
- Frequency up to 200MHz
- Capacitanze up to 5000uF
- as cheap as possible
Other functions are not needed but those which are needed... -
Thanks, I will study carefully the datasheet of the UP9510P and the layout of the board and see what pin goes where in the pcb and determine if there is anything that doesn't seem right....
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I have two chips that could be the driver?
One is labeled uP9510P on the other side of the board, the other is ON 45491 on the bottom (just right of DVI connector), which one is the Driver IC? Thanks...
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I need to look carefully at the video multiple times since it is not english and need to figure out what is saying in the subtitles.
I have access to 3-4 DMM, my best ones are ASITA MD591 (daily driver) and Metrix MX22 (backup). Both of them are not state of the art but is all I have and can afford at the moment. Thanks....Leave a comment:
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I understand a bit what you're saying. I'm still learning so please be patient
I believe the problem lies on the two bottom phases at this point, still can't figure what my problem is. Thanks....Leave a comment:
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Also wanted to add this, I don't know how I missed it, measuring the pads of the four Capacitors I've removed ( C77, C80, C78, C79 ), I get very low resistance to ground. I get 0.1-0.2Ohms on the negative pad (right side, facing the GPU die) and I get 0.9-1 ohm on the left pad ( left side, facing the video output connectors). Is this normal? Thanks.Leave a comment:
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Hi!!
So the card is working, outputing pictures, without two mosfet?
- Yes, the card is working fine without two mosfets. It loads drivers correctly and can run 3D software. Tested briefly of course to avoid stressing the working Mosfets.
Have you tested these mosfet out from circuit? Both shorted?
- I have tested them, I wasn't sure if they were shorted, ordered new ones from Aliexpress just in case, but the problem persists.
Have you check path from driver ic to gate? With dmm can you measure frequency on gate? Or on driver ic...Leave a comment:
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Thank you for your information
What you are saying makes sense in my measurements.
I measured all Mosfets (the 4x ones that are currently on the board and the pads of the two removed mosfets) and there is no short (Source - Drain, Drain - Gate, Gate - Source)
PS, I didn't want to remove the crystal oscillator, it just fell off when applying heat on the back of the card during removal of the Coils
At this point I'm still not sure where my short is. When connecting the coil pads (using a tweezer), thus simulating the coil is still there, I get short circuit...Leave a comment:
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I highly appreciate your time for helping me
Here are the measurements you asked:
The two mosfets North:
On the left: Source: 10.22 Megaohm and slowly decreasing - Gate: OL (open) - Drain: 5.6 Megaohm and slowly decreasing
On the right: Source: 0.1 Ohm (short) - Gate: 18.8 Megaohm and slowly decreasing - Drain: 10.35 Megaohm and slowly decreasing
The two mosfets South:
On the left: Source: 12.22 K-ohm - Gate: 25 K-Ohm - Drain: 14 Megaohm and slowly decreasing
On the right: Source: 0.1 Ohm (short) - Gate: 23.63...Leave a comment:
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Pads of the Mosfet on the left:
Source: 12.74 kOhm - Gate: 25.7 kOhm - Drain: 17.3 Megaohms and slowly decreasing (open)
Pads of the Mosfet on the right:
Source: 0.1 ohm (short) - Gate: 26.64 kOhm - Drain: 12.74 kOhm...Leave a comment:
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Help me find the short circuit on this WORKING Nvidia GTX1650
Hi all,
Recently picked up this GTX1650 at a local flea market for a low price and wanted to use it on my secondary PC. I first tested the card and saw the fan spin for a split second and then nothing. Immediately I thought of a short circuit. Disassembled and found a shorted SMD capacitor, injected voltage into it (1V/4A) and two Mosfets got hot immediately (QN3103 & QN3107). Desoldered these Mosfets and the card turned back to life.
Bought replacements from Aliexpress and replaced them afterwards. Tried the card but still the saw the fan spin for a split second... -
Re: New Members - please post your introductions here
Hello all!
I'm aaronkatrini, a passionate user of older hardware, I enjoy using and collecting them. I'm here to learn a little of how I can do basic repairs if needed. Thanks for having me
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