1977-8 Zenith 23” metal cabinet CCII

[LADR]

Got this set today for free from an estate sale, still has it’s cart. First off, the screens were set way too high. Adjusting them made the picture look a whole lot better. One side of the screen is much more bright than the other, I’m thinking an electrolytic. Cleaned up all the lovely cigarette paste inside and out, the set looks quite nice.

[AlanInSitges]

F chassis? Those are nice-looking sets.

[LADR]

The set has been acting up for the past few days. The red and blue screen controls are either off or all the way up, no in between. Set has good sound, but no video. I found a few broken solder joints in the tuner module, and after touching them up and putting it back in the set, no difference at all. The brightness and contrast control seems to be doing nothing. I checked for bad solder joints on all the modules and nothing. What do y’all think.

[maxhifi]

Originally Posted by LADR

The set has been acting up for the past few days. The red and blue screen controls are either off or all the way up, no in between. Set has good sound, but no video. I found a few broken solder joints in the tuner module, and after touching them up and putting it back in the set, no difference at all. The brightness and contrast control seems to be doing nothing. I checked for bad solder joints on all the modules and nothing. What do y’all think.

Sounds like the screen controls are either dirty or bad. Have you cleaned them?

[LADR]

Originally Posted by maxhifi

Sounds like the screen controls are either dirty or bad. Have you cleaned them?

Yes

[zeno]

Resolder the ceramic resistor packs on the 9-88 & 9-89 modules.
It was a must do on all repairs. Whenever you see them resolder them.

G-2 controls were known to get bad spots on these. Funny thing is 2 of
them went for $2.50 & the 3rd were for $1.40, go figure. Needls to say
we only bought the cheap ones.
63-10137,8 & 9 IIRC. You can use them from an old hybrid chassis also.
If you change one cut the 3 leads at the pot, easier than unsoldering.
Be sure to use plastic mounts as there is boost on them.

Never had shading BUT on all other brands its common. Almost always
the 'lytic on the 200V supply to the 3 video outs. I think its in the main can ?
Second choice is a horz blanking problem.

73 Zeno
LFOD !

BTW I thinks this is a 25GC45. Let me know the chassis & I can look things up for you

[LADR]

Originally Posted by zeno

Resolder the ceramic resistor packs on the 9-88 & 9-89 modules.
It was a must do on all repairs. Whenever you see them resolder them.

G-2 controls were known to get bad spots on these. Funny thing is 2 of
them went for $2.50 & the 3rd were for $1.40, go figure. Needls to say
we only bought the cheap ones.
63-10137,8 & 9 IIRC. You can use them from an old hybrid chassis also.
If you change one cut the 3 leads at the pot, easier than unsoldering.
Be sure to use plastic mounts as there is boost on them.

Never had shading BUT on all other brands its common. Almost always
the 'lytic on the 200V supply to the 3 video outs. I think its in the main can ?
Second choice is a horz blanking problem.

73 Zeno
LFOD !

BTW I thinks this is a 25GC45. Let me know the chassis & I can look things up for you

You had the chassis close, but, it’s a 25JC45. That cap is indeed in the main filter. I didn’t even think about resoldering the two resistor packs, I’ll take care of that now.

[LADR]

Zeno, I resoldered the connections on those ceramic resistor packs, and that did it!

[LADR]

The set it done. I replaced the 10uf section of the filter can and that took care of the shading. Still need to find a neon dial lamp, but besides that, it’s a great set.

[zeno]

Bulb is just an NE-2 (short version IIRC). That cap can make a
huge improvement in pix quality. Sometimes it will even look
like a bad CRT. Whenever you get a SS set that just dont "look right"
change it.

73 Zeno
LFOD !

[TVTim]

Very nice catch.