[TechAssist] Re: Fw: Toshiba CF-315
- From: "Gonzalo N Arrivas" <gna2000@xxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Sun, 30 Sep 2001 12:53:12 -0700
Bad connections IC501 and its shield case will cause same symptom. If IC501
is bad, replace it with the kit p/n 23309608.
Gonzalo N. Arrivas, CET Pittsburg, CA
http://www.etechhelponline.com
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----- Original Message -----
From: "fantaj" <fantaj@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Sunday, September 30, 2001 12:20 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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