Got one of these for next to nothing. Previous owner said he got it from a friend and after a couple months it just didn't turn on anymore (completely dead).
PSU board is shot. What I've been able to diagnose so far:
- one primary side MOSFET is completely shorted (0 ohms on all pins)
- the other primary side MOSFET is completely open
- 1 resistor close to them "exploded" (lost part of the outer casing)
- another resistor below the above one is shorted (and was covered in soot)
- 4 amp mains fuse is open
Apart from one tiny Capxon (what else), none of the caps are bulging, even though they're all junk brands (Capxon KF/KM and Elite EB/PF). I expected much better from a monitor that retailed for 900 USD or more when it was new..
I'm not very experienced when it comes to fixing up the primary side of power supplies, so I kinda need help here. In a scenario like this, are there other components that are likely to be bad? If so, which parts would that be?
I'm suspecting the SMPS controller IC (Philips/NXP TEA1507P) could be damaged as well, but I don't know for sure (and much less how to test it in this situation).
As this is a 23" 1920x1200 LCD monitor with a S-IPS panel, I wouldn't mind spending a couple more bucks on fixing it than usual.
One thing that annoys me a bit is that the pin headers (to the inverter and the mainboard) aren't labeled at all apart from the pin count, so I'll have to look at the SM all the time..
Talking about service manuals.. I managed to find a sort of incomplete one. The PSU diagram is there but the PCB shot is useless as it's a regular image (think JPG), not a vector graphic. When will people learn to create proper PDFs!?
"Servicemanual" (almost 13MB)
https://cdn.badcaps-static.com/pdfs/...0af21ab69b.pdf
PSU board diagram is on page 10, the almost useless PCB shot on page 11 (blurry mess)
There are a few inconsistencies between the PDF and what's on my PSU board though, which doesn't make this any easier I think.
The completely shorted MOSFET is marked 7135 on the PCB (and in the manual), and is a ST P10NK80ZFP (800V, 0.78ohm, 9A), whereas in the manual it's a P7NK80ZFP (800V, 1.5ohm, 5.2A)
The open one is marked 7113 on the PCB and is a ST P20NM60 (matches the manual).
More inconsistencies with the resistors next to them. The one that "blew up" was still readable, and said 0.22 ohm. It's marked 3139 on the PCB. The manual however says that's supposed to be a 0.15 ohm (1W 1%) resistor.
The other resistor below that one (marked 3115 on the PCB) was covered in soot from it's blown up brother, and my attempt at cleaning proved to be a little bit too effective, as I wiped the markings off as well
According to the manual that's also supposed to be 0.15 ohm (1W 1%)
The SMPS controller IC, which might or might not be damaged due to the blown-up parts is a Philips/NXP TEA1517P.
I've attached all the datasheets to this post, as well as a bunch of photos from before desoldering parts to check them out of circuit.
Sorry for the bad solder-side photos.. the huge ground traces with solder on them didn't really help with their reflections. I'll try to take some better ones later
So.. what do you suggest checking apart from the bad parts I already found? Should I just go ahead and order the parts as per the manual and hope it doesn't end in fireworks..?
PSU board is shot. What I've been able to diagnose so far:
- one primary side MOSFET is completely shorted (0 ohms on all pins)
- the other primary side MOSFET is completely open
- 1 resistor close to them "exploded" (lost part of the outer casing)
- another resistor below the above one is shorted (and was covered in soot)
- 4 amp mains fuse is open
Apart from one tiny Capxon (what else), none of the caps are bulging, even though they're all junk brands (Capxon KF/KM and Elite EB/PF). I expected much better from a monitor that retailed for 900 USD or more when it was new..
I'm not very experienced when it comes to fixing up the primary side of power supplies, so I kinda need help here. In a scenario like this, are there other components that are likely to be bad? If so, which parts would that be?
I'm suspecting the SMPS controller IC (Philips/NXP TEA1507P) could be damaged as well, but I don't know for sure (and much less how to test it in this situation).
As this is a 23" 1920x1200 LCD monitor with a S-IPS panel, I wouldn't mind spending a couple more bucks on fixing it than usual.
One thing that annoys me a bit is that the pin headers (to the inverter and the mainboard) aren't labeled at all apart from the pin count, so I'll have to look at the SM all the time..
Talking about service manuals.. I managed to find a sort of incomplete one. The PSU diagram is there but the PCB shot is useless as it's a regular image (think JPG), not a vector graphic. When will people learn to create proper PDFs!?
"Servicemanual" (almost 13MB)
https://cdn.badcaps-static.com/pdfs/...0af21ab69b.pdf
PSU board diagram is on page 10, the almost useless PCB shot on page 11 (blurry mess)
There are a few inconsistencies between the PDF and what's on my PSU board though, which doesn't make this any easier I think.
The completely shorted MOSFET is marked 7135 on the PCB (and in the manual), and is a ST P10NK80ZFP (800V, 0.78ohm, 9A), whereas in the manual it's a P7NK80ZFP (800V, 1.5ohm, 5.2A)
The open one is marked 7113 on the PCB and is a ST P20NM60 (matches the manual).
More inconsistencies with the resistors next to them. The one that "blew up" was still readable, and said 0.22 ohm. It's marked 3139 on the PCB. The manual however says that's supposed to be a 0.15 ohm (1W 1%) resistor.
The other resistor below that one (marked 3115 on the PCB) was covered in soot from it's blown up brother, and my attempt at cleaning proved to be a little bit too effective, as I wiped the markings off as well
According to the manual that's also supposed to be 0.15 ohm (1W 1%)
The SMPS controller IC, which might or might not be damaged due to the blown-up parts is a Philips/NXP TEA1517P.
I've attached all the datasheets to this post, as well as a bunch of photos from before desoldering parts to check them out of circuit.
Sorry for the bad solder-side photos.. the huge ground traces with solder on them didn't really help with their reflections. I'll try to take some better ones later
So.. what do you suggest checking apart from the bad parts I already found? Should I just go ahead and order the parts as per the manual and hope it doesn't end in fireworks..?
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