2000 RCA Entertainment Series 27" console model G27647 problem

[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?

[pac.attack76]

I give up. My whole goal here was to save crt sets from ending up in the dump. I got close with this one and now it looks like this

[JohnCT]

Originally Posted by pac.attack76

I give up. My whole goal here was to save crt sets from ending up in the dump. I got close with this one and now it looks like this

That could be a corrupt eeprom. These chassis *must* have the tuner grounds soldered and the two heatsinks tabs - the horiz output and the LV regulator.

Not soldering these grounds will absolutely corrupt eeproms. I remember changing an eeprom in one of these in warranty for no audio. Two days later it was back. These chassis were new at that time and we had little experience with them. A call to RCA about the failed eeprom was to solder the tuner and heatsink ground tabs. RCA issued a "goldenrod" about this about a week after I ran into this.

You could solder the grounds and then get into the service menu and reset the vert height and centering. Normal values are between 0-63 IIRC but sometimes we'd see values that didn't make sense, like numbers in the hundreds or with letters instead of digits.

John

[pac.attack76]

Originally Posted by JohnCT

That could be a corrupt eeprom. These chassis *must* have the tuner grounds soldered and the two heatsinks tabs - the horiz output and the LV regulator.

Not soldering these grounds will absolutely corrupt eeproms. I remember changing an eeprom in one of these in warranty for no audio. Two days later it was back. These chassis were new at that time and we had little experience with them. A call to RCA about the failed eeprom was to solder the tuner and heatsink ground tabs. RCA issued a "goldenrod" about this about a week after I ran into this.

You could solder the grounds and then get into the service menu and reset the vert height and centering. Normal values are between 0-63 IIRC but sometimes we'd see values that didn't make sense, like numbers in the hundreds or with letters instead of digits.

John

Hey John. I turned it back on and it's running normal again. Should I go ahead with the grounds?

[Jeffhs]

Originally Posted by pac.attack76

Hey John. I turned it back on and it's running normal again. Should I go ahead with the grounds?

The TV may be working normally now, but the next time the ground connections come loose the problem will return and could corrupt the EEPROM chip. I am no expert on these by any means; I only worked on TVs, the old tube-operated ones, as a hobby years ago (my basement was full of them, trash finds, in the '70s) and have absolutely no experience at all with modern solid-state sets. Your best bet would be to look for someone who is well-versed in this type of repair, but as I said, I would at least try resoldering the grounds; this may get the set working again unless the EEPROM chip was damaged by static charges, etc., in which case the only solution would be to replace the chip. In a TV this old (23 years), it may not even be worth repairing; in fact, some repair shops may not even touch it.

[JohnCT]

Originally Posted by pac.attack76

Hey John. I turned it back on and it's running normal again. Should I go ahead with the grounds?

The grounds should be done in any case. Your eeprom isn't corrupted because they don't "fix" themselves when they are.

It would be the tuner grounds specifically that are causing your issue with the picture even when using AV inputs. The ground to the jungle IC runs through the tuner (stupidly).

The tuner is a surface mount affair and is delicate work. You have to remove the tuner cover (soldered down) and then solder the tuner perimeter and several ground pins in the middle of the tuner.

There is an alternative if you don't plan to use the tuner - solder a ground wire from the cage around the micro and jungle IC and bypass the tuner directly. I've never done this but if you want to try, the point you need to solder your wire to would be on the lower right corner of the tuner when the board is oriented where the tuner input connector is facing straight up. There is a ground point that has a wire soldered to it on the top side of the board.

John