I fixed this set about two months ago by replacing R607 , Q601, Q602 ,Q502
and did a lot of resoldering on back of power supply board and flyback just
went over joints that looked weak . Ran until now and blew again. I tried
replacing same parts and it ran for about 5 min. then blew again. Well I
pulled the power supply board and only could find one VDR on it ,VDR601.
When I measured it with VOM I cant get any ohm reading I guess its infinity
reading. R607 blew again and Q601 and Q602. R644 I get 2.4 ohm reading .
Suppose to be 2.2ohm . Guess I will get another H.O.T for Q 502 and this
time try 100 Watt light bulb in place of fuse. Hope Its not Bad flyback.
Would I get 5 min with a bad flyback. Been a long time since I have had TV
repair school! 1975 and I wasnt good at it then. Help.
Thanks!
Bill

Bill

Do an ESR test on all the caps in the horiz section, and in the power
supply. Change the flyback assy, and also check that the horiz drive pulses
to the HOT are in specs once the set is powered up again. I have had the
horiz driver transformer that feeds the HOT get intermittent to its leads
that are soldered down to the board. You will also have to change all the
blown parts again.

When the HOT blows, especially a number of times, there is a possibility
that some windings in the flyback became defective, and thus the flyback
should be changed.

This is why I tell people to send their sets out to an experienced service
centre to have their sets fixed, even if they have a degree in electrical
engineering. In the end, if you are not very used to working on these,
properly trained, and properly equipped, it can cost a lot more in lost
time, and replacing parts many times over to find the fault.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Bill" wrote in message
...
I fixed this set about two months ago by replacing R607 , Q601, Q602 ,Q502
and did a lot of resoldering on back of power supply board and flyback just
went over joints that looked weak . Ran until now and blew again. I tried
replacing same parts and it ran for about 5 min. then blew again. Well I
pulled the power supply board and only could find one VDR on it ,VDR601.
When I measured it with VOM I cant get any ohm reading I guess its infinity
reading. R607 blew again and Q601 and Q602. R644 I get 2.4 ohm reading .
Suppose to be 2.2ohm . Guess I will get another H.O.T for Q 502 and this
time try 100 Watt light bulb in place of fuse. Hope Its not Bad flyback.
Would I get 5 min with a bad flyback. Been a long time since I have had TV
repair school! 1975 and I wasnt good at it then. Help.
Thanks!
Bill

Bill