Hi Bob,
I should have said in my "update", I didn't list all the tests I performed.
There is no coupling capacitor to the yoke in this TV.
For now, I put the "DOG" aside so I can work on other "stuff".
Brad
>> Hi,
>>
>> Here is an update, but TV is not repaired yet:
>>
>> Note: TV chassis is L03.1UAA and I have SM.
>>
>> The vertical deflection system uses discreet components.
>> There is no vertical amplifier IC, which is common in all other TVs
>> I have worked on. I replaced "2463" 100/50 and "2446" 470/16.
>> Both measured a loss of capacitance, but it made no improvement.
>> "2465" 10/160 tested very good, however I replaced it, but it didn't
>> fix the problem.
>>
>> I tested the two output transistors out of circuit (AOK). I tested other
>> transistors in circuit. Also tested various components in the vertical
>> deflection circuits. Note: I originally checked solder joints and soldered
>> several joints that seem to lack good solder bond.
>>
>> I used a Yoke tester and checked both windings individually
>> after I separated the windings at a terminal. Both windings read
>> "good", but one winding had a higher reading than the other. I
>> repeated the test incase of a poor test lead(s) connection, but the results
>> were the same!
>>
>> Scoping the two inputs to the vertical amp, the "+drive" signal doesn't
>> match "-drive" waveform, although it's "inverted". The +drive signal is
>> "abnormal".
>> Brad
>>
>>
>>
>> >> >Hi,
>>
>> > I bought the service manual and found out that AN7225N is not the
>> >vertical IC.
>>
>> > If I repair this TV (in my spare time), I will let everyone know what
>> >part(s) caused this problem.
>>
>> > Brad
>>
>> >>>
>> >>Hi,
>>
>> >> I have a Philips TV model 20PT6245/37 (mfg 05/05) in my
>> >>service shop with a loss of vertical deflection. I do not have SM.
>>
>> >> For a moment after the TV is turned on, there is some vertical deflection,
>> >>but it collapsed into a single horizontal line in the middle.
>>
>> >> I checked solder joints at the vertical IC, resoldered them anyway, but
>> >>this had no effect. Note: I soldered other joints too. Flexing and tapping
>> >>on mother board has no effect.
>>
>> >> I couldn't find pin out info on the vertical IC AN7225N on the
>> >>web so I could make additional tests.
>>
>> >> Thanks in advance, Brad
>>
>> >> Before you type your password, credit card number, etc.,
>> >> be sure there is no active keystroke logger (spyware) in your PC.- Hide
quoted text -
>
>> - Show quoted text -
>
>If you have a scope, it and a dc voltmeter, you should be able to
>check the voltages on the output transistors to make sure they are
>biased correctly and then check the waveforms. If you don't see any
>sawtooth at the output of the pair of output transistors, that's your
>problem. If you do have a sawtooth there, then maybe the capactior
>coupleing the output to the deflection coils is open/
>
>Bob Hofmann