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Dear members,
I have a linear variable power supply with unknown brand name that I used for voltage injection.
Then it failed. I discovered that its transistors (Q1 and Q2) are shorted.
In addition, I discovered that its zener diodes are defective.
I can replace the burned transistors.
But I do not know the model of the zener diodes. the model number is not marked on the zener diodes.
Therefore, I cannot replace the zener diodes.
I do not want to test the zener diodes in a test circuit to discover their model or value.
no schematics are available... -
Laptop Question
Hello,
I'm working on a Lenovo T460 that has been having trouble charging as of late. Its worked well since I've owned it for a few years. When I went to use it the other day it was dead and wouldn't turn on (was sitting on an Anker 65W GaN charger). After some fiddling with the charger I got it to turn on and start charging, but seemed like the charger was not working as it should (took a few plug and unplug cycles to get it to start charging).
A day later it was dead again and wouldn't boot/charge no matter what I did. No lights or anything when... -
Hello, I have 2 old chargers for Sony DV, and I found the same resistor fuse dead. Fuse is a crossing component : 0,47 Ohms (0,125W deduced because the lenght is 3mm). But I can’t find the same for buy.
So, I want to replace by another like 0 Ohms, 1 Ohms 0,125W,
It is the same please ? I guess it’s the same, the only change should be the time to burn ? Thanks... -
Hi
I am trying to repair an ancient Dell 2209WA Monitor which suddenly shut off with a pop sound. On investigation found that one of the fusible resistors had blown. Further investigation identified multiple components as faulty because of which the fusible resistor blew. Please refer the attached circuit diagram showing the components that were found to be damaged.
1. FR950 - blown fusible resistor - 0.2 Ohm 1W
2. Q950 - shorted Q950 MOSFET - 650V 10A N Channel Mosfet
3. R835 - Blown Resistor - 20KOhm SMD resistor
4. D930 - Shorted Schottkey Diode... -
Hi to all forum members,
Got this faulty 350 watt atx psu dirt cheap from a local online seller as i am keen to use it as a learning tool to repair faulty power supply.
The faulty part is quite obvious from the burn area near the 16pin KA7500 BD pwm. The fuse is still intact with good continuity.
Upon power on ac, there is 5vdc standby power on cathode of diode D14 and about 10vdc on cathode of diode D13.(This should be the aux power to generate the 12v and 5v rail.)
Initially i replace the two burned resistors near my marked red arrow to 200 ohm resistor...
Working...
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