1978 Sylvania console problems

[jg6364]

I have had this set for several years. About a year ago the HV tripler was replaced. Just recently I was trying to play it and the picture is scrambled. The audio is great and if you turn the fine tuning ring the picture will go completely black just when you think it is going to clear up. I'm attaching several pictures and a video What should I be looking for? I pulled a lot of the transistors and cleaned the connections just in case that was the problem but no luck.











video http://youtu.be/DWW_RvhQrag

[compucat]

Looks a lot like agc overload. Try backing off the agc control slightly if it has one.

[jg6364]

Originally Posted by compucat

Looks a lot like agc overload. Try backing off the agc control slightly if it has one.

I didn't see any adjustment but there are two AGC det ic's in the deflector module.

[sampson159]

i have the same chassis set.agc ic s were a fairly common issue with this chassis.i may have an extra module for this.not sure but the 19 inch chassis had the same ic s.turn off the afc and perma tint.try to fine tune it.you can also try another channel if your using a converter box.pretty simple,straight forward sets.no frills,just simple chassis with a really fine crt.love these sets and worked on many of them.

[jg6364]

Originally Posted by sampson159

i have the same chassis set.agc ic s were a fairly common issue with this chassis.i may have an extra module for this.not sure but the 19 inch chassis had the same ic s.turn off the afc and perma tint.try to fine tune it.you can also try another channel if your using a converter box.pretty simple,straight forward sets.no frills,just simple chassis with a really fine crt.love these sets and worked on many of them.

I would love to get this set back working. It always had a great picture until this. Let me know if you have the modules or the agc IC . I tried the other things you suggested, nothing worked. If it's the module that I'm thinking it is, the one with the agc det ic then the module number would be 32-41658-3. That IC is IC400 in the diagram and the number is 15-43312-1. I have no idea how to check those. I don't have a schematic or service manual for this set. Any help at all is really appreciated.

Jeff

[zeno]

The set has the look of outside interference to it.
Try a different source if you havent.
Also try reseating the 3 modules & check the IF cable.
Do a little tapping around.
If you post the model & chassis I will pull the manual
& see what its got for AGC, to long ago to remember.

73 Zeno

[zeno]

OOPS just noticed E45-01. I will look it up tomorrow.

73 Zeno

[jg6364]

Originally Posted by zeno

OOPS just noticed E45-01. I will look it up tomorrow.

73 Zeno

Thanks so much , glad you saw the chassis number LOL. The model number is CL7237P-1

Jeff

[jg6364]

I cleaned the connections on the modules and cleaned the tuner. I pulled up some color bars and switched between channels 2 thru 6 no change.

[sampson159]

looks more like a horizontal oscillator problem.the first module is known for cold solder joints around the if ground plate.its in the center of the module.the 3rd module is horizontal/vertical.also been known to have cold joints.is this the original black matrix crt?they make a pretty picture when they are good.didnt last long,usually about 3-4 years but still the best picture.a flat chassis zenith with this crt would be the ultimate set!good luck with this set.

[jg6364]

Originally Posted by sampson159

looks more like a horizontal oscillator problem.the first module is known for cold solder joints around the if ground plate.its in the center of the module.the 3rd module is horizontal/vertical.also been known to have cold joints.is this the original black matrix crt?they make a pretty picture when they are good.didnt last long,usually about 3-4 years but still the best picture.a flat chassis zenith with this crt would be the ultimate set!good luck with this set.

Yes it's the original CRT. It's dated February 1978, same as the cabinet. I will check the 1st module again. I've checked the third module, could not find any bad solder joints. I even checked the electrolytic caps. They all checked between 5 to 10% tolerance.

[jg6364]

Originally Posted by sampson159

looks more like a horizontal oscillator problem.the first module is known for cold solder joints around the if ground plate.its in the center of the module.the 3rd module is horizontal/vertical.also been known to have cold joints.is this the original black matrix crt?they make a pretty picture when they are good.didnt last long,usually about 3-4 years but still the best picture.a flat chassis zenith with this crt would be the ultimate set!good luck with this set.

I found a few cracked solder joints on the shielding but that was it. I fixed those and cleaned another connection on the module pins. At times it plays a little better but still not fixed. Thanks for all the info on this type of set. I really appreciate it.





The top shielding was removed for the picture below.

[Jon A.]

Keep on trucking, I consider this one a keeper.

The IC in the pic with the shielding removed, it doesn't look to be soldered in, have you re-seated it?

[zeno]

OK got the Sams.
IC 400 & Q202 are the AGC semis. Also some eletrolytics
C420, 215, 216, & 211. Also C130 1mf probably mounted
on tuner at AGC terminal.
There is NO AGC adjust at all.
Normal range at IF board pins are
TA22 4.43- 11.31VDC
TA21 4.62- 9.56VDC
Tough to call this one could be AGC or IF dont think video.
Hard to tell not being there.........

PM sent

73 Zeno

[jg6364]

Originally Posted by zeno

OK got the Sams.
IC 400 & Q202 are the AGC semis. Also some eletrolytics
C420, 215, 216, & 211. Also C130 1mf probably mounted
on tuner at AGC terminal.
There is NO AGC adjust at all.
Normal range at IF board pins are
TA22 4.43- 11.31VDC
TA21 4.62- 9.56VDC
Tough to call this one could be AGC or IF dont think video.
Hard to tell not being there.........

PM sent

73 Zeno

All I could do with is IC400 and Q202 was clean and check the connections.
C420 is a .22uf cap and it checked perfect.

C215 is 10uf 16V it check 13.8uf so I changed it with a 10uf 50V it checked as 10.3uf.

C216 is 1uf 50V it checked 1.4uf so I changed it with the same that checked as .974 uf.

C211 is 4.7uf 25V it checked 6.08uf so I changed it with 4.7uf 50V that checked 4.97uf

on C130, there were 3 of the 1uf 50V capacitors on the tuner. They all checked 1.31 or higher so I changed them all with 3 new 1uf 50V caps.

TA22 was 4.05V
TA21 was 4.64V

Thanks for all the information. I'm willing to try any suggestions.

Here is the link to a video of it playing after replacing the caps.
http://youtu.be/A7nO-bvzaHc