2000 RCA Entertainment Series 27" console model G27647 problem

[rcaman]

i think i have a new 27'' ctc203 chassis i will look and see.

[pac.attack76]

Originally Posted by rcaman

i think i have a new 27'' ctc203 chassis i will look and see.

Cool. Let me know.

[rcaman]

Did you get the parts i sent you..

[pac.attack76]

Originally Posted by rcaman

Did you get the parts i sent you..

Yes, I'm gonna be putting in soon. I was hoping to replace entire chassis but idk.

[pac.attack76]

Got the ic switched out today and found the 100ohm 1A thermistor just laying on the board next to the fuse. Does anyone have one? I might have one laying around but I doubt it. Usually have everything but what I really need.

[damen]

Those degaussing thermistors fell apart on many brands. I used to just solder the wires back on.

[pac.attack76]

Originally Posted by damen

Those degaussing thermistors fell apart on many brands. I used to just solder the wires back on.

U mean the disc back on the 2 wires?

[pac.attack76]

Ok, new ic put in. Finally got everything back in and tried it out today. Focus keeps going in and out about every second. Never seen that before. Also was surprised to see something called warranty clock. Ne ver in 40 years of working on tvs have I ever seen something like that. Kinda cool. Says has operated 65,000 hours and was first turned on 4-11-2000.

[damen]

That focus problem can be caused by a broken/loose connection in the focus circuit. Anywhere from the flyback, focus control, CRT socket, or CRT focus pin.

[JohnCT]

Originally Posted by pac.attack76

Ok, new ic put in. Finally got everything back in and tried it out today. Focus keeps going in and out about every second. Never seen that before. Also was surprised to see something called warranty clock. Ne ver in 40 years of working on tvs have I ever seen something like that. Kinda cool. Says has operated 65,000 hours and was first turned on 4-11-2000.

That tube looks weak from that pic... Hopefully it will balance out when run a few hours.

Focus drift can be coming from anywhere, including the CRT itself. Sometimes in a quiet room you can hear the arc beat in time with the focus drift. A rubber tube probed around might tell you where the drift is coming from.

The focus drift is probably coming from inside the CRT socket assy or (yikes) behind the socket guide. Given the history of this TV being outside, the possibility of it trapping moisture from the air inside the socke, behind the socket guide, or inside the flyback is very real.

The CRT socket assy has a built in spark gap to ground out any wayward internal CRT arcing to ground so as not to back up into the kine drive circuits.

The assy is normally held together with melted "rivets" that can be easily removed. Carefully separate the halves being careful not to let the individual metal pins get away. You will see the spark gap inside, and if it's been arcing, you will see some greenish smutz in that area. Cleaning won't help but with a Dremel and a fine tip, you can grind out the arced area leaving fresh white plastic. Go over it with a bright light and magnification and make sure to remove absolutely all of the green smutz.

If inside the socket is clean, the problem might be between the plastic guide pin and the neck of the tube. When these were made, most of those guide pins were pushed on and held in place with clear RTV. If it's glued, it's hard to get behind. If you try prying to help, use a plastic spatula instead of a metal screwdriver. If you get the guide off, look for that same green crap behind the guide (if it's white - if it's black, you won't see it). A replacement guide is best but you can try soaking the guide in ISO for a while and brush it out. Clean the neck of the tube and carefully remove as much RTV as you can. I wouldn't replace the RTV however.

A third option is the flyback itself is arcing internally at the focus divider/adjustment. If so, you might be able to hear it with your rubber tube stethoscope. You can try removing the fly and putting it in a box with a hair dryer blowing into it on low for a few hours and hopefully drive any moisture out.


John

[pac.attack76]

Funny enough, this is the first time the focus has done this. All the other times it never did this. The inside and back has never been wet. I'll go back in a couple days and look everything over again. The tubes not as bad as the pic shows. My camera on my phone messed up awhile back and now mostly everything I take a pic of doesn't look all that great. Also need to check my connections inside. I might have left something unplugged as the left speaker doesn't have sound.

[pac.attack76]

https://youtu.be/tBHlg-NCjQo

I put a video up on you tube showing the focus. Seems like speed of flicker depends on what's being show on screen. Sometimes it speeds up and sometimes it slowes down.

[JohnCT]

Originally Posted by pac.attack76

https://youtu.be/tBHlg-NCjQo

I put a video up on you tube showing the focus. Seems like speed of flicker depends on what's being show on screen. Sometimes it speeds up and sometimes it slowes down.

Have you listened for it? That type of focus pulsing is often audible as well. In a dead quiet room, listen for a soft pop in time with the focus change. If you have a HV probe, you can measure the focus voltage right at the CRT pin. You will have to refocus with the meter in circuit.

John

[pac.attack76]

Originally Posted by JohnCT

Have you listened for it? That type of focus pulsing is often audible as well. In a dead quiet room, listen for a soft pop in time with the focus change. If you have a HV probe, you can measure the focus voltage right at the CRT pin. You will have to refocus with the meter in circuit.

John

Unfortunately, I don't have a probe. I did listen for sound but all I remember hearing was the low hum usually associated with these sets. I will try again when it's dead quiet to see if I notice anything. Only thing that's bothering me is all the other times I ran this set, there was no focus pulsing. Could it be something caused from removing the chassis last time , transport of the board from a to b, and when I put it back in?

[pac.attack76]

Pulled it back out today and tried everything I could think of. Listening for a tick or any sound in timing with the pulse but nothing. Someone said I should try running the focus back and forth on the flyback. Does that seem feasible?