[TechAssist] Re: Fw: Toshiba CF-315
- From: AL LEATHERMAN <alleathe@xxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Sun, 30 Sep 2001 15:39:17 -0400
fUZZ,
YOU CHECKED THAT 300 OHM R DID YOU? Maybe there has to be more on the good
end.Doesn't the chip depend of the hor sync from video to lock in?Maybe
another pin on the jungle is low or missing a pulse.resulting in "sinking"
the video pulse. Good luck. al
May God give us strength
Al's TV
224 Rt. 46
Mine Hill, NJ. 07803
973-361-5796
alleathe@xxxxxxxxxxxxx
----- Original Message -----
From: "fantaj" <fantaj@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Sunday, September 30, 2001 3:20 PM
Subject: [TechAssist] Fw: Toshiba CF-315
>
> Toshiba, CF315,
> an old classic, similar to this circuit are CF915, CF917,
> Symptoms, turn the set on, chanel 2 comes on, set totally out
> of
> sync, looks more like the horizontal, as soon as you press the channel up
or
> down buttons, the screen gets dark, sound disappears, and the channel
> numbers
> start running, like bad AFT, once ina while,AT RANDOM, it locks to a
> station,
> sound comes on, but the video totally out of sync again.
> this thing has a video amp
> Q201, I have good video waveform there, then the video goes thru a cap
C301,
> and feeds to pin 57 of the jungle TA7777, thru a 300 ohm resistor, here is
> the strange thing, at this end of the 300 ohms, I have perfect video, the
> other end to pin 57, the sync input, sam calls out about 1.5VPP, which I
> have
> more than that this side,but at pin 57, that is almost a flat line, just
> millivolts of video.!!!!!!!! Either sam is wrong, which I don't beleive it
> is, but what's going on, check/replaced all parts around that area,
isolated
> sections, in total dispair, I replaced the TA7777, almost sure that was
not
> the problem, ONE TRACK MIND, no matter, always the same! The AFC pulse
from
> the flyback is perfect, pin 59, and looks ok on frequency, , there is not
> much left, I will try subbing the 503KHZ resonator today, and see what
> happens, in case I did have an AFT problem, carefully tweaked the aft
coil,
> ended up subbing the whole coil, as I have one new, that I use for test
> purposes, no help.
> Anyway, I am at my wits end, today, I am going to use my
> tuner
> subber, see if the tuner control has a problem, if that fails, will, give
it
> back I guess, let someone else give it a try.
> Please any Help greatly appreciated.
> fuzzzzzz
>
>
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