PVM-5041Q misbehaving, sporadic black/white.

[Mark]

Hey there duders! Long time no see.

I picked up two PVM-5041Qs at an auction in Florida this week. One refuses to behave properly, only outputting color over composite (video in) sporadically. It seems stuck in some kind of black and white mode except for random moments of digital sanity (it's given me color over composite exactly once before flipping itself back to black and white while I was calibrating).

Before you ask if I have the blue only button pressed: nope. I checked the blue only button about a billion times now. Oddly enough, enabling the option actually does change the brightness of the black and white color bars, which is suspicious to me.

RGB/Component works fine. I know what you're thinking: if the other inputs work, why bother trying to get composite working? I was planning on giving this little guy away as a gift or potential prize at my local retro game store, Video Game Rescue in Jacksonville, FL.

[Mark]

Bumping to let you guys know I tracked down the culprit and fixed my little monitor.

On the B board inside my 5041Q (left board when looking at monitor from back, right board when viewing from the front) the large IC was poorly mounted originally, a trace may have been weak and a tiny little surface mount resistor could have been failing. I figured this through trial and error with an engineer friend of mine from work.

We pointed a focused (tiny) heatgun at components until the screen flipped back into color, then used cold spray on components and some tapping with a non-metallic screwdriver on components until it failed back into black and white. We eventually narrowed down the issue to a small area on the B board and decided to reflow the IC's pins and a resistor.

Screen is happily playing the Persona 4 intro video and gameplay demo on loop for now until I'm sure the fix is good. :3

[lukelinker]

Hi Mark. I know this is digging up an old thread but I'm having the same problem and others may have it in the future (with leaky 90's caps and what-not). Do you remember what area of the B board this IC was located, or what/where your new resistor went? Any help is greatly appreciated.

Also anyone know where a schematic for a/our PVM-5041Q is? I've found schematics/repair manuals for my other Sony CRTs but not this little guy..

Thanks everybody.

[staffanu]

Old thread, but maybe this can be of use to someone...

I fixed the same (or at least very similar) issue on a PVM-5041q today. After refloating the through-hole mounted chips and connectors, the display would still randomly flip into black/white, especially when warm (leaving it off for an hour and it always worked fine for about 10 minutes).

In my case only PAL decoding was affected. NTSC (and presumable RGB/Component but I didn't check) worked just fine. Given the problem probably SECAM didn't work either, but I cannot test that.

The problem turned out to be a bad solder on CV102, which is a variable capacitor for the 4.43 MHz VXO. I found it by using cold spray and at the end just poking the components one by one using a wooden stick. Having found it I did verify that the VXO randomly oscillated at around 10 MHz when the picture was B/W, and when touching the capacitor and the screen flipped into color, the VXO indeed ran nicely at 4.43 MHz. I do not have a frequency counter to adjust it properly but my oscilloscope can show two decimals of the frequency, and the picture now looks great!

So, it seems that bad connections is indeed a very common problem on these monitors. However, refloating every single component is a lot of work and I'm glad I didn't have to go there...

[Artemio]

Just to document another case of reflow to fix, in my case it was IC124.. it had a lousy soldering job, maybe a repair? I started reflowing it and all connectors, but found it easier to mostly remove the solder and use new solder since it didn't flow smoothly.