A few months ago a friend of mine gave me a Dell E172Fpb monitor to have a look at. No backlight, flashing power button. Found the forums and tried everything advised, to no avail. Threw it out. Couple of days ago another friend gave me a Dell E176Fpb. Power button constant green, no backlight (can see the Dell 'Self test feature check' moving around the screen (No video sgnal applied)). Checked all the bad solder joints, all the caps, all the transistors, put it back together, no joy. One of the threads mentions checking voltage at pin 9 of TL1451 dual PWM chip, 0 volts, I started poking around the switch transistors from the video board With my DVM when I noticed through the gaps on the metal housing of the LCD that the backlights were on. Re-soldered the SMT legs of the transistors and all is OK. I can only assume there was a dry joint on one of the transistor legs that caused the fault. Has been on test for about 6 hours so far.
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Hi:
I am trying to repair this amplifier that I've bought as faulty. I've found some transistors damaged, the ones where I am drawing a red circle.
With the final transistors not yet installed (the expensive ones), I've started to measure some voltages:
Where I am supposed to have 1.12V (base Q524/Q523) I am reading -42V..................both channels don't seem ok.
Where I am supposed to have -1.12V (base Q526/Q525) I am reading -44V..................both channels don't seem ok.
I removed and tested Q514,Q516 & Q513,Q515 but the analyzer... -
Welcome badcaps, repairing a Crosshair 15, in need of transistor specifics. Received a broken laptop that's was perfect for repair, threw away the looser transistors in a haste... Should and could have salvaged them.
In any case, I will be posting all my discoveries to this forum as a thanks in advance. Thanks in advance lol.
P.S. If anyone is familiar with such things, as in, If anyone knows that MSI uses one or one of a few types of transistors when marked with a number please let me know how I can find more specifics before I start throwing hail marys. -
Hello,
While ago I replaced those big filter caps to that amplifier. After that started to happen. I connected the amplifier normally to the mains and almost immediately several transistors burned out. I really didn't do anything else (at least on purpose) than replaced those big caps C801 and C802.
After that I replaced those burned transistors (I can't remember exactly what they were) and measured all the others, and now everything should be ok. But, when I power up that amplifier part with two bench power supplies connected in series there is obviously still something... -
Hello everyone,
I've got a Benq power board of a XL2540K monitor which suffered from a power cut and is since defective / won't turn on. It's got obvious defects, some blown resistors, some burning around the drain pin of a MOSFET...
... and some 6-pin IC I struggle identifying, that is driving said MOSFET.
The IC is labeled as IC601, so someone with a circuit schematic could probably identify it really quick, unfortunately I can't find the schematics.
In other power boards of Benq for which I did find the schematics, IC601 is an 8-pin NCP1200 PWM controller - I suppose... -
Hi All.
Does anyone have any reference materials or something I can use to try troubleshooting a BenQ TH681? Google unfortunately has turned up zip. I did find a service manual for a W series BenQ but that is pretty much useless, it's more a glorified user manual. A list of voltages would be great as I suspect my mainboard is faulty, the colour wheel voltage is not dipping like it should.
The one I am troubleshooting now was originally overheating after a lamp replacement. It originally would take 2 minutes or so for it to shut off and blink the temp and lamp lights...