stealthtronics
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Dec 16, 2006, 8:14 AM
Post #4 of 4
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Re: [electronics] Magnavox: MS3252S431(Shutdown)
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Electronicman,
I have a Philips MS3250/32M800 that came in with shorted HOT transistor 7461 bu4508dx but good fuse. Replaced 7461 With NTE 2353 and checked for usual components bad and found none. Unit would not power up so I replaced c2455 and it was a little weak but still no change.
The recitfier was not getting power due to the relay not engaing, so I bypassed the relay and unit would now turn on when power button was pushed and would have good horizontal and vertical and good sound and reception with a bright screen with washed out colors but would only stay on for about 10 seconds then shut down. Has 127 volts on HOT collector but some voltages seem off on the other windings and HV seem to be weak along with G2 adjustment on flyback making little difference.
I was to the point of replacing the flyback, but since you have the same problem, does yours come on without bypassing the relay and how does your picture look ? I also had to unplug the degaussing coil to turn it on along with jumpering the relay, and have checked all diodes and caps for shorts or opens and have'nt found anything. Have even checked the typical R3340 resistor on the picture tube board that often opens and all is good. If this unit sounds like yours maybe we can both figure it out. The thermistors seem to be getting hot so I installed a bigger one but still shuts down after 10-15 seconds.
I was told G2 on the flyback is very touchy on these sets and needs to be within 25 volts or the set shuts down, but G2 makes little difference and does'nt blank out screen with retrace like usual, so I was thinking the flyback must be bad. Let me know if you had any change after changing the flyback ? Also if you have a schematic could I get a copy, cause I am working without one and your chassis should be close enough to use for a reference and if you have any voltage measurements like on the flyback, maybe we can compare notes ? Later, Stealthtronics
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