View Full Version : Zenith Z1920W


TVTim
11-17-2015, 09:11 PM
So, my Zenith works great but has these lines on the top of the screen. What is causing it?

radiotvnut
11-17-2015, 10:05 PM
I don't remember the value; but, there is a capacitor in the vertical circuit that is failing (probably something between a 47uf and 220uf). How old is this set and what main module does it use?

You really need to address this before using the set because that failing capacitor will likely cause other parts to fail. On newer sets with a vertical output IC, it will eventually cause the IC to fail.

TVTim
11-17-2015, 11:56 PM
I don't remember the value; but, there is a capacitor in the vertical circuit that is failing (probably something between a 47uf and 220uf). How old is this set and what main module does it use?

You really need to address this before using the set because that failing capacitor will likely cause other parts to fail. On newer sets with a vertical output IC, it will eventually cause the IC to fail.

I will have to check on the module number. The set is about 1983 or so.

tvcollector
11-18-2015, 04:48 AM
I have a 1976 Sanyo set that has deveolped that problem.. The pic gets real bright, and when you turn down the brightness the color looks weird and you see the retrace lines at the top even more.. Looks like it could be too much HV or something..

rrrhre2s
11-18-2015, 07:34 AM
Sanyo had a problem with the resistors on the CRT board changing value.

Unsolder one end of the chain and check, on the screen grid of the CRT.

rrrhre2s

zeno
11-18-2015, 07:53 AM
My money is on the filter cap for the 200 V feeding the video outs.
It happens to every brand set. Its usually a 4.7 mfd. To find
it go to CRT SKT. There are 3 transistors each with an about 18K ohm
2W resistor feeding the collectors. Where the resistors join is
the 200 V. The cap is off that point sometimes on the CRT SKT or
usually the main board near the FBT. Just follow the wires. There may
also be a coil in series.
Some sets dont have a board at the CRT SKT, everythings on the main PCB.

73 Zeno:smoke:

I have a 1976 Sanyo set that has deveolped that problem.. The pic gets real bright, and when you turn down the brightness the color looks weird and you see the retrace lines at the top even more.. Looks like it could be too much HV or something..

zeno
11-18-2015, 08:00 AM
9-181 set & yes change all the 'lytics in the V out. Also look
under the big filter cap for mung leaking out.
Finally check the yoke plug on the HV module
for overheating at connector & on the PCB. That should
keep it running another 30 + yrs.

73 Zeno:smoke:

I will have to check on the module number. The set is about 1983 or so.

TVTim
11-18-2015, 08:44 AM
These lines are on the on top two inches or so of the screen.

Thank you everyone for the input.

DavGoodlin
11-18-2015, 09:40 AM
Tim, Is that the hospital set you got from me? I never opened it, so the caps are it:yes:

TVTim
11-18-2015, 08:31 PM
Tim, Is that the hospital set you got from me? I never opened it, so the caps are it:yes:

No Dave, whole different set.

radiotvnut
11-18-2015, 09:53 PM
While you're in there, change the electrolytic capacitor on the start-up board (the little board that's mounted on the horizontal output heatsink. This capacitor won't cause your problem; but, it will cause a "dead set" and it's a common failure.

TVTim
11-21-2015, 09:05 PM
While you're in there, change the electrolytic capacitor on the start-up board (the little board that's mounted on the horizontal output heatsink. This capacitor won't cause your problem; but, it will cause a "dead set" and it's a common failure.

Thank you. We will do that.