Users browsing this forum: Google [Bot] and 19 guests. Posted: Thu Jul 19, am. Posted: Sat Jul 21, am. I tried to do an RGB mod on this TV but failed I only had success with external red and green signals showing up on screen

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Users browsing this forum: Google [Bot] and 19 guests. Posted: Thu Jul 19, am. Posted: Sat Jul 21, am. I tried to do an RGB mod on this TV but failed I only had success with external red and green signals showing up on screen I am also confused about the whole sync thing because this TV has RF only input even though it's from So I've been ripping my hair out all day trying to figure out this problem.

Did nothing to the TV or board prior to this. Discharged the CRT like normal, into the ground strap. Didn't touch the board with a probe or iron. Been poking and prodding, taking voltage and continuity tests I guess. It feels like there is no rhyme or reason to the numbers, I'm more used to fairly simple automotive circuits. Does it switch over to DC on the one side of the transformer? Because the numbers make even less sense on that end. Negative readings on the DMM, "normal" readings, super high readings, fluctuating readings etc.

Anyway, I just started dumping info into Photoshop to try and make any sense of it. Either the entire board blew up somehow, without any marks, smells, smoke, or indication..

Why am I immediately getting 64v at the fuse? Fuse appears to be fine, 0 resistance and has continuity. If anyone can make any sense of this, that'd be great. Not finding much helpful info on the net. Had to vent a bit. Edit: Deleted image because it was basically all wrong. This whole post can probably be ignored.

It's just a single chirp. Bird chirp is a decent way to describe it but very quick and subtle. I tried to listen for where it was coming from but was never sure. Just sounds like something getting charged with a small amount of juice.

I actually found a big electronics supplier relatively close by who has new-old stock of the NEC 2SK mosfet. Ordered a handful of them because why not.

Trying not to get my hopes up. I'm really kinda sad that just as I was looking forward to plugging set back in as-is, borrowing the friends SFC, run the two systems at the same time, and then trying to take base reference shots and some side by side shots with my 20" for comparison and then some after the work Annnd then it's dead for no apparent reason.

I still can't comprehend what could've happened. Curious if others have stories like this, maybe a anode discharge killing a TV or just..

All the other parts for the mod arrived today. There is one spot on the board that I am hoping isn't going to be a problem: Keep in mind, I only started messing with this connection after I saw it was dead and was looking for issues. It's right at the edge of the main board and I wondered if maybe the cable was tweaked enough to cause an issue at the solder joints. Then I potentially made it worse or fixed it from there.. For some reason, the spot where that cable attached appeared to have old flux on it and the joints looked a little crusty.

I thought I'd just go in there and clean it up and replace the solder but shame on me. As soon as I touched those points with the iron, it was crackling like bacon and it looked like two of the pads came loose. So now this went into full recovery mode, I removed the whole cable, two pads were half lifted, I cleaned it all up, scrapped a little mask away next to a couple pins to give them more solder surface, reattached it all with fresh solder and a small amount of hot glue between the cable clip and board to help give the cable some extra strength against all the flexing.

Now all I can do is hope for the best. Posted: Sun Jul 22, pm. I've exhausted my google abilities. I can't find a service manual for it either. Short of that, I may have to blindly look for capacitors and resistors near the chip if I can't find this.

The set has an on screen menu and also claims to have analog closed caption capabilities, which would be a preferable way to inject the signal, but without the service manual, I'm kind of lost on what to do here. Posted: Mon Jul 23, am. Interesting, though kind of a letdown too. Here is another document that may interest you. Posted: Mon Jul 23, pm. Posted: Tue Jul 24, am.

Posted: Tue Jul 24, pm. Had a look and the chassis appears to be a match for the one I am working on except yours appears to have surface mounts whereas mine is throughole. Check out the schematic in this service manual Also appears that most of the components are already in place for Component and Composite inputs. Hey there! I've been reading this thread for a while now and decided to make an account here. I found a service manual for a similar Toshiba CRT that uses the same chip with a different four numbers at the end , and it seems to have an OSD RGB in that I can pull from, which is shown here: My only problem is that I can't figure out what the blanking pin is.

If anyone could help me find it, I'd greatly appreciate it. Posted: Wed Jul 25, pm. Good and bad news I guess. Good news is my friend came over with his 1chip SFC, I set my 20" Toshiba back up and we messed with that. There was some slight geometry issues that were bothering me, and I guess I got too impatient to fix them before, but I decided to pop the back off and have another go at it.

Ended up redoing pretty much all the color settings and tweaking the geometry with a little magnet and yoke help. Definitely better than it was. Still not perfect but its good enough.

It's really annoying that something like Streets of Rage on Genesis will cut into the overscan part a bit, so you shrink the picture down, and then other games will have boarders that aren't supposed to be showing.

The other thing that sucks is the i flicker. Feels like it only stands out with white text on a black background, but boy is it noticeable. Nothing that can be done about this right? So I guess my DMM isn't capable of testing these for some reason. Maybe their gate voltage is too high or something. Super depressing. Pulled up all my schematics and Photoshop stuff back out and went back to probing. Kind of at a loss at this point.

Haven't been able to find any related Orion IC datasheet. I still think whatever is wrong has to be so incredibly obvious but not to me. Edit: Guess I'll take this to the next level and start probing the working 20" TV for some sort of general reference. That answers that question.

Posted: Mon Jul 30, pm. Hi All. I have a 27" Toshiba - 27af The mod is successful and everything looks really good. If I adjust the brightness it appears that it is always there but only visible on certain colors. I have played around with ground points, sync termination, cable length, and various other things that I have picked up from these forums but I am not able to get rid of it.

It is on present on the s-video, component, or composite inputs. Posted: Tue Jul 31, am. Sorry to post back to back but its been a week and this is separate I guess.

Decided to try the mux on the working, previously switch-modded 20" Toshiba. All hooked up now annnd I've got no color. Wired it up like the diagram I made earlier. Diodes added on the OSD side. Blanking has a 1. Injected before the factory termination resistor R into the chip if that matters. It appears I do have color in the OSD overlay itself. I think I can see color from the game in there. Oh yea, I should've asked earlier but, does this disable the regular component jacks per say?

Tried something plugged into it and its just giving me an unsync'd image in purple.


LA7673 datasheet

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LA7673 Datasheet and LA7673 manual



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