1983 Zenith system 3 console - Videokarma.org TV - Video

Dreamsbeard · #1 10-31-2015, 11:36 AM

Hello fellow CRT nut Zombies (its halloween so why not)

Just a quick question for you today ; I brought home a 1983 zenith system 3 console with a 9-214 main board (strange as I tought that was advance system 3 board aprox 1985). The problem is, I need to touch up the grayscale but I can't find the individual screen potentiometers.

Main screen and focus are on the flyback...but where are individual gun adjustment?

Thanks!

zeno · #2 10-31-2015, 12:11 PM

IIRC those have AKB so no pots to adjust. See if it is in
the service menu. WHENEVER you change anything write the
old setting down !!!

Press and hold MENU until the user menu disappears (5 - 10 sec.)
*The remote or the keyboard on the set can be used
Immediately press 9, 8, 7, 6, ENTER (this will bring up the service menu)
* On models with 10 buttons keyboard, without delay, press simultaneously ADJ. RIGHT and CH+

* On model with 6 button key board, without delay, press simultaneously VOL+ and CH -

Press and hold MENU until the menu disappears
The set should now be in the service menu mode.
To access most of the features selection 00 needs to be toggled from 0 to 1
After your adjustments 00 needs to be toggled from 1 to 0
To exit the service menu press ENTER

73 Zeno

Quote:

Originally Posted by Dreamsbeard

Hello fellow CRT nut Zombies (its halloween so why not)

Just a quick question for you today ; I brought home a 1983 zenith system 3 console with a 9-214 main board (strange as I tought that was advance system 3 board aprox 1985). The problem is, I need to touch up the grayscale but I can't find the individual screen potentiometers.

Main screen and focus are on the flyback...but where are individual gun adjustment?

Thanks!

zeno · #3 10-31-2015, 12:15 PM

Thinking about it I dont think this set has a menu.
If not you gotta find out why its off. Usually CRT
but sometimes something else.

Dreamsbeard · #4 10-31-2015, 01:19 PM

I believe you are right in saying this set hasn't got a menu... can't see any menu key on the keypad. So, could this mean the the main board was a 9-160 or 181 and has been replace with a newer one and now I can't solve my grayscale problem?

rrrhre2s · #5 10-31-2015, 03:58 PM

There is a 150 k resistor in the AKB circuit that will cause the CRT to look bad.

There is a 4 pin square jumper on some sets for setting the screen with the cathodes locked at 150v for proper tracking.

Run the set awhile and see if all of the R G B transistor heat sinks get warm, be careful to be sure the set is off around 250 volts DC there. They are (3) in a row (left to right) almost directly in the middle of the cabinet back near where the support holds down the module (Black heat sinks).

This system is very hard to get an accurate DC voltage reading on the cathodes of the CRT.

One of the transistors may have failed.

Also check the connections on the Thick Film Ceramic resistor network.

In the same general area, they are very fragile.

rrrhre2s

radiotvnut · #6 10-31-2015, 10:48 PM

The board is probably the correct one. There should be a paper diagram inside the cabinet that will list the correct module numbers and location.