[TechAssist] Re: Help-mag.PTV775-Ah01 low b+
- From: "Damon" <damon101@xxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Wed, 26 Sep 2001 23:54:00 -0500
As for the retrace line problem , obviously adjust the screens. But do check
your cathode supply = 240Vdc. Bad? D801/R815 is ihvt supply (0.27
ohm1/2Watt) d801 is 4835 1303 7094 fast switching Soft recovery diode.
r812 and r 828 (both 68k ohm 1/4Watt) couple the 130v supply to the cathode
side of d801, which makes this a boosted power supply.
Also, this tv does have AKB circuits on all 3 crts. AKB samplers are list as
Q105/205/305 on RGB bds. Sample is clipped by D101 (12v max) and D106 (0.7 v
min), so your DC voltage has to be between 0.7 to 12V. Clippers on G and B
are same number except for 1st digit (100, 200, 300).
Q303 (103/203) is a biasing transistor for Q301/302. And z303 (if used) is a
clamper for the emitter of q301/collector of q302. Both are NPN's so is this
a Push Push AMP? It's arranged like a Push-Pull. Good luck, this is about as
detailed as I can get.
----- Original Message -----
From: "bob" <bob_whigt@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, September 26, 2001 6:27 PM
Subject: [TechAssist] Re: Help-mag.PTV775-Ah01 low b+
>
> Thank you damon for the info.ken and jason for the cross.
> This set has two hor-outputsQ802 and Q906 = 2539. Q906 was the first one i
> pulled it check as a good intedgrated output it is next to the flyback
Q802
> was shorted on all 3 legs i had no data on it so i thought it was a
switcher
> .prombley cause i got a head cold why i missed that Q802 and Q906 had the
> same #..lol
> Thank you so much for helping me with this .I had a nte2353 hanging so i
> replaced Q802 set is working but there's fant retrace lines somtimes.I
check
> a.m........Have a Great day .......bob
> ELECTRON WORLD
> GUTHRIE KY- Original Message -----
> From: Damon <damon101@xxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Tuesday, September 25, 2001 7:16 PM
> Subject: [TechAssist] Re: Help-mag.PTV775-Ah01 low b+
>
>
> >
> > Q802 is is the horiz output for the deflection yokes. Part #4835 1304
> 8074,
> > 2SD2539. There is no cross in ECG or NTE. You'll have to get it from MCM
> > Electronics
> >
> > www.mcmelectronics.com
> >
> > Check D806 and 808---retrace diodes; and c817 and c819 0.011uf and ???
> > (unknown value) respectively....these are about the only parts that
would
> > cause a repeat failure. I doubt you'll see these parts bad.
> >
> > HV isn't associated with this circuit at all. it has its own circuit
> section
> > which provides tighter regulation of HV.
> > ----- Original Message -----
> > From: "bob" <bob_whigt@xxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Tuesday, September 25, 2001 9:33 PM
> > Subject: [TechAssist] Re: Help-mag.PTV775-Ah01 low b+
> >
> >
> > >
> > > Hello guys
> > > Found Q802 shorted # D2539 i cant cross,any generics for it?I thank it
> is
> > a
> > > high speed switch the location is hor- left side of flyback on the
long
> > > heatsink ,left side of a smaller npn.Any one seen this trans. short
> before
> > > on a PTV775.I beginning to thank i might find out that the h.v.
spitter
> > took
> > > it out.Thanks for the help...........Have a great day ........bob
> > > ELECTRON WORLD
> > > GUTHRIE KY
> > >>
> >
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> >
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