1979 GTE Sylvania GT Matic CX9164W chassis E24-3

[pac.attack76]

Ok I'll check later today and update

[vortalexfan]

I have the console version of this TV, mine still works yet suprisingly enough but its missing the "lock" for the front panel that opens up for the user screen adjustments so the user screen adjustment door is open all the time, which is also where the speaker is so the audio doesn't sound very good because the cover isn't properly baffling the speaker.

[pac.attack76]

Can't find anything in that mess. So much going on in there. I took a few shots hoping someone recognizes something. I see the back side of the output, screws and wires running down.

[Alex KL-1]

Yes, seems to be difficult; too many wires and so on. The solution is to follow each flyback wire, and see what ones ends at diodes, to measure them.
Not seem to have any diode in the HO transistor socket.
I sse some relatively fat diode near the socket with "24" number on it. Is impossible to know if is relative to flyback, without following the flyback wires.
Sometimes, in the hurry, I simply measure every diode near flyback at time I'm worked with TV's (is faster anyway).
The suspects are removed and measured externally to be sure.
I see one small diode in parallel with a small capacitor in one photo. These one seems to be improbable, but anyway, is good to check on the DMM diode scale.

Other thing, since manufacturers not want to use 2 times same funcion component, is good to measure on diode scale the HO transistor you removed from TV. Measure from collector to emmiter. In one side, basicaaly with negative (black) proble connected to collector (case), and negative to emmiter, the DMM will measure something between 0.5 and 0.8, and, for another side (reverse, with red onde connected to case), will measure OL. If measures this manner, the damper diode is internal/integrated to transistor case.

[Alex KL-1]

Originally Posted by vortalexfan

I have the console version of this TV, mine still works yet suprisingly enough but its missing the "lock" for the front panel that opens up for the user screen adjustments so the user screen adjustment door is open all the time, which is also where the speaker is so the audio doesn't sound very good because the cover isn't properly baffling the speaker.

I have same problem with my 17" Toshiba from 1987; the controls are exposed (the "lock" protuding part broken). I need to solve it before the grandchildrens visits here

[JohnCT]

Originally Posted by pac.attack76

Can't find anything in that mess. So much going on in there. I took a few shots hoping someone recognizes something. I see the back side of the output, screws and wires running down.

There are three wires on the back of the horiz out socket. The wire that's attached to one of the screw posts is the collector. Follow that down to the board where it will be connected to the damper diode assuming the TV has an external one.

What is the part number of the horiz output?


John

[pac.attack76]

I can't find any numbers on that output. Maybe if we could figure out which one this chassis is designed to use.

[JohnCT]

Originally Posted by pac.attack76

I can't find any numbers on that output. Maybe if we could figure out which one this chassis is designed to use.

I scrapped all of my GTE/Philips schematics years ago along with most of my SAMS of those years.

If anyone has any SAMS still, it's in 1751 folder 2.

John

[damen]

Sams 1751-2 shows the damper diode as "SC448". It's on the circuit board between the yoke socket and the focus control area. It's between the horizontal linearity coil, L470, and a large cap labeled C448. Sorry, can't post pictures.

[pac.attack76]

And I just remembered the diagram is on the inside of the back cover showing horiz output is Q402.

[pac.attack76]

So I'm testing sc448 with the same setting? Does output need to be installed during test?

[Alex KL-1]

Probably, it will measure low like the first measurement, since this diode can be in same circuit of the HOT.
Measure using the diode scale on DMM; then, you can desolder it, and check if the low value remains on the part, or in the circuit board (at same PCB location).

[JohnCT]

Originally Posted by pac.attack76

So I'm testing sc448 with the same setting? Does output need to be installed during test?

Yes on the same DMM setting (200 ohm scale), no on does it need to be installed, but it doesn't matter either way. You've confirmed the horiz output is not shorted, so on a resistance test of the diode, it will read "open" as if it's not even there.

The damper should also read open on your meter for resistance the way the horiz output did if it's good, or at least 100K ohms in circuit which is essentially open for this discussion.

If the diode reads short (I think you had something like an 8 ohm short to ground), then unsolder one end of the diode or remove it completely and test again. If it's reading that same 8 ohms out of circuit, then the diode is shorted and you need to replace it. If the diode reads open, something else is shorting the B+ to ground. Reinstall the diode and horiz out and we'll go further (retrace cap would be next).

John

[pac.attack76]

Ok, hopefully today or tomorrow ill find out.

[pac.attack76]

Near the yoke socket, I found two 448. I can't find anything beginning with SC.