CurtPalme.com Home Theater Forum

[Jonnycp]

hi All

Newbie here having just bought a fairly nice condition d50 for little money. Less than 1000hrs, no visible wear, 9/10 easilly.
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Just set it up but after a little while the red tube flashes brigh, stays on and uniform output. With no video, blue and green are black, red pretty bright, with video all three show image as normall.

Is this possibly dodgy connector on neck of tube? The set has no dust and looks in good condition, wondering if i need to remove the whole tube connector. If so, is this easy? Cant find much info on this.

Any help will be very gratefull- am looking forward to decent, non reddish, blacks

Cheers
Jon, UK

[Curt Palme]

Sounds like you're in the UK? PLease throw in something as to your location, it's helpful when we troubleshoot in case you need parts or some help.

Two possibilities: bad red tube, or bad red CRT video amp/socket. It can be other issues, but those are the most likely.

All three CRT sockets/video amps are identical, so with a bit of work you can swap them, or at least put the red one onto the green tube. All the wires disconnect from it, and it can be transferred to the green. Disconnect the green, and leave it disconnected. THe set will run with the red tube wires not connected to a CRT socket.

See if the green acts up. if so, the video amp within that metal box is bad. If it's solid, then chances are the red has an intermittent short in the neck of the tube. If so, try tapping on the neck of the red tube to see if you can create the flashing once the tube is warm. (I guess do that before swapping sockets, since it's easier!).

Tap gently with the handle end of a screwdriver. Sony tubes are pretty darn reliable, but it's possible.

Other even rarer faults would be a bad A board (input board that controls the red video amp), or a bad PA (high voltage) board that controls the G2 voltage going to the red CRT tube. I doubt these last two possibilities though..

[Curt Palme]

Sounds like you're in the UK? PLease throw in something as to your location, it's helpful when we troubleshoot in case you need parts or some help.

Two possibilities: bad red tube, or bad red CRT video amp/socket. It can be other issues, but those are the most likely.

All three CRT sockets/video amps are identical, so with a bit of work you can swap them, or at least put the red one onto the green tube. All the wires disconnect from it, and it can be transferred to the green. Disconnect the green, and leave it disconnected. THe set will run with the red tube wires not connected to a CRT socket.

See if the green acts up. if so, the video amp within that metal box is bad. If it's solid, then chances are the red has an intermittent short in the neck of the tube. If so, try tapping on the neck of the red tube to see if you can create the flashing once the tube is warm. (I guess do that before swapping sockets, since it's easier!).

Tap gently with the handle end of a screwdriver. Sony tubes are pretty darn reliable, but it's possible.

Other even rarer faults would be a bad A board (input board that controls the red video amp), or a bad PA (high voltage) board that controls the G2 voltage going to the red CRT tube. I doubt these last two possibilities though..

[Jonnycp]

Hi Curt, thanks for speedy reply. Yes am Uk and on the south coast , Brighton.

I just tried tapping the tube neck with back end of a pen, nothing intermittent there- still have briht red- can see the flyback raster even- not so good to spend time like that.

Just to confirm, i can change just the neck amplifier/ electronics/heatsink? Leave the looms where they are. I.e red Electronics on green tube, green neck electronics on the table, red loom flying?

[Curt Palme]

Yes, that's correct. The only wire that will travel with the red CRT socket is the thick focus wire. It actually comes out (pulls out) of the actual CRT socket, but since the red wire is the longest, I'd just move it and the video amp over to the green. You might need to undo some wire fasteners, but those untwist.

Let me know what happens.

Oh, for easier access, there are two screws, one on each side of the chassis that loosen so that the rear fan panel flips down.

[Curt Palme]

Yes, that's correct. The only wire that will travel with the red CRT socket is the thick focus wire. It actually comes out (pulls out) of the actual CRT socket, but since the red wire is the longest, I'd just move it and the video amp over to the green. You might need to undo some wire fasteners, but those untwist.

Let me know what happens.

Oh, for easier access, there are two screws, one on each side of the chassis that loosen so that the rear fan panel flips down.

[Jonnycp]

Thanks Curt, realtime support, am real grateful over here! O

I swapped over video amp, green fine in this config so i guess amps okay. What do you suggest next step?

Will re-attach back to normal, contact clean red tube pins and try again. If still issues, guess i need to move all green electronics onto red? That would be interesting....

[Curt Palme]

No, the yokes and stuff on the necks of the tubes only have to do with the deflection, anything controlling the tube brightness will be connected to the base of the tube, ie the CRT socket/amp.

[Curt Palme]

No, the yokes and stuff on the necks of the tubes only have to do with the deflection, anything controlling the tube brightness will be connected to the base of the tube, ie the CRT socket/amp.

[Curt Palme]

OK, next step: Under the green lens is the PA board. Going down through the component side near the front of the board, in the middle, is a single Philips screw that you need to loosen. Once it's loose, that PA board and plastic tray slides out. IN a row beside each other are relatively thick R G and B colored wires. Those are the master brightness for each tube. INterchange the red and green wires. Now the master red brightness is going to the green and vice versa.

DO NOT leave those wires disconnected! DOing so will spot burn a tube. So don't leave any wire loose when powering up.

See if that switches the problem to the green tube.

[Curt Palme]

OK, next step: Under the green lens is the PA board. Going down through the component side near the front of the board, in the middle, is a single Philips screw that you need to loosen. Once it's loose, that PA board and plastic tray slides out. IN a row beside each other are relatively thick R G and B colored wires. Those are the master brightness for each tube. INterchange the red and green wires. Now the master red brightness is going to the green and vice versa.

DO NOT leave those wires disconnected! DOing so will spot burn a tube. So don't leave any wire loose when powering up.

See if that switches the problem to the green tube.

[Jonnycp]

Wahay, we have green torchlight!- are you going to tell me bosh, replace 50c fet? Job done- that bwould e too good to be true!

[Curt Palme]

I don't give out actual component servicing info, as that's how I make a living, but if you're a board level tech, go for it. If not, I've got good working boards for $50 + shipping.

Cheers!

[Curt Palme]

I don't give out actual component servicing info, as that's how I make a living, but if you're a board level tech, go for it. If not, I've got good working boards for $50 + shipping.

Cheers!