Troubleshooting horizontal on SS tvs
 

OK working on one of those Sony micro tvs. i had only vertical line. trye checking volts. on the horiz osc, i only had supply volts. after a while i had way too high volts on the transitor. got hot. now i dont even have vertical line. did i kill the flyback? can you kill the fly troubleshooting? heck. i never worked on a SS tv before. only tube stuff

I'll never say never, but I don't think there's a way you can kill a flyback unless you intentionally wired it to fail. There were a few instances of extreme HV runaway if a shutdown circuit was bypassed or if a retrace capacitor suddenly opened that could damage a fly, but these were in color TVs.

Going on the assumption that this Sony TV uses an actual flyback as opposed to a separate HV transformer and a horiz deflection transformer, the fact you had a vertical line means the HV was there, so the horiz osc was running.

Before you do anything else, verify the resistance of the horiz yoke windings, and then check to see they're properly connected to the board. Also, look for a capacitor that couples the yoke to the fly. If the yoke is open or not loading the fly, it will cause problems for the HV section.

My guess is that the horiz output transistor failed (again, assuming a flyback setup).

Is there a schematic we can see?

John

It would help others here if you gave the model number of what your working on. Is the transistor mounted on a heat sink? Because the very early Sony solid state sets could get quite warm. Your biggest help would be to have a schematic and a plan to replace all the electrolytic caps in it.

Sony 5-303. i know the caps need to be replaced, but you dont learn by bulk replacment, and i want to at least get a raster before i waste my time doing a bulk recap.

If I'm reading the schematic properly (5-303J - Elektrotanya), then the yoke unplugs.

With the TV unplugged from the power, unplug the yoke and verify the yoke's horizontal winding continuity between the red and blue wires on the yoke plug. Not sure what the resistance would be here but under 20 ohms likely.

Next, with the yoke still unplugged, measure the resistance across the H pins on the connector where the yoke would plug in. This will be the flyback primary and should also be pretty low resistance.

To verify the wiring on the chassis, unplug the power and connect one end of your meter to the power switch (on) and the other to the collector of X21 horizontal output. This should read under two ohms.

Measure the switch (on pos) to ground. If it reads short, the horiz output probably shorted out.

EDIT: since you had a vertical line indicating some HV but no horiz deflection, and since the horiz windings are directly across the flyback primary, I'm hoping you just have an open connection between the yoke and chassis. If this is a printed circuit, look for a cracked/ringed solder joint around the yoke plug.



John

actually i goofed. i dont have vertical, but i kept loosing my horizontal due to an overheated transistor. i took quess to which electrolytic was bad. bridged one in. now my horiz drive transistor isnt over heating. now, ill have to try to see if i can get vertical back. once i get a raster ill go ahead an recap it.