[TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''

  • From: <hartstv@xxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Fri, 25 Jul 2003 18:04:35 -0300

Larry,Can't see how hooking up the HOT is going to help in t/s this power
supply.Tks for offering to send the training manual but will fight this set
on the week-end & see if I can find something I missed or over looked.BTY in
a previous email I said nte 177,that should have read NTE 577.Tks again for
your assistance....
Don of HARTS-TVCR-ASC
9 Robert St,Oromocto,NB,Canada,E2V3N2
Tel-506-357-9785,Fax-506-357-6010
hartstv@xxxxxxxxxxx



----- Original Message -----
From: "Larry E." <videotech@xxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Friday, July 25, 2003 5:47 PM
Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''


> Don, connecting the collector of the HOT shouldn`t hurt anything in the
standby
> mode, Horizontal circuit is not active in standby mode, there is no drive
signal
> at the base of the HOT during standby, just B+ to the HOT collector and B+
> to the horizontal driver transistors collector (from the 15v line) That B+
should
>
> be checked in standby if you haven`t already confirmed it, I`ve seen the
driver
> transformer T4301 have bad solder connections and I`ve had a couple where
> pin 5 was open or R314 was open killing the B+ to the driver transistor,
but
> that
> shouldn`t cause the voltage to go up and down on pin 16 of U4101. Have you
> tried pulling one end of the secondary diodes one at a time? (CR4118,
etc.) I
> can mail you the tech training manual and the troubleshooting guide if you
want
> me to, don`t know how much they`d help but it probably wouldn`t hurt .
> Larry E
> hartstv@xxxxxxxxxxx wrote:
>
> > Larry,yes C4118 was replaced & I tryed both a 177 & 580,but read that a
177
> > is a better sub??Really don't want to connect C of HOT until I get this
p/s
> > working properly.The Q4601 cct i will dive into again & see if I missed
> > something...........
> > Don of HARTS-TVCR-ASC
> > 9 Robert St,Oromocto,NB,Canada,E2V3N2
> > Tel-506-357-9785,Fax-506-357-6010
> > hartstv@xxxxxxxxxxx
> >
> > ----- Original Message -----
> > From: "Larry E." <videotech@xxxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Friday, July 25, 2003 2:49 PM
> > Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''
> >
> > > Don, if the original C4104 was 15uf @ 50v I would replace it with that
> > value
> > > Pin 3 is correct so that`s not the problem. You mentioned in another
> > > post that you replaced CR4118 with a NTE177, that`s not a good
> > > substitute, has to be an ECG/NTE 580, the C voltage on Q4601
> > > appears to be a problem, it should be a steady 13.1 volts in standby
> > > did you check replace C4118 off pin 16 of U4101 yet? What
> > > happens to the voltages in the switchmode if you connect the collector
> > > of the HOT but don`t turn the set on? Larry
> > > Larry Eastman
> > > American TV & Electronics
> > > Crystal River, Fl. 34428
> > > 352-795-0124
> > >
> > > hartstv@xxxxxxxxxxx wrote:
> > >
> > > > Tks for your reply,Larry.Here are the values of the orginal caps
removed
> > > > from the smps;
> > > > C4102=2.2ufd/100v
> > > > C4104=15ufd/50v
> > > > C4108=47ufd/50v
> > > > The voltage at Q4101 is varying from 159vdc to 164vdc.
> > > > The voltage on the collector pad of the HOT Q4401 is varying from
13vdc
> > to
> > > > 40vdc;NOTE this is without the collector of HOT connected to pad &
yes
> > I'm
> > > > using the correct grounds.
> > > > Pin 3 of U4101 is varying from 0vdc to .013vdc.
> > > > I know there are hot & cold grounds for these measurements.The HOT
> > collector
> > > > voltage is low because the chopper is not in it's proper duty
cycle.This
> > is
> > > > the same voltage measured at the cathode of CR4116,the 145vdc
source.
> > > > I did replace C4104 with a 4.7/100v cap,as per your email but have
same
> > > > voltage readings.What I don't understand is the orginal cap was
> > > > 15ufd/50v.Man this is wierd?? Tks again for your help...regards...
> > > > Don of HARTS-TVCR-ASC
> > > > 9 Robert St,Oromocto,NB,Canada,E2V3N2
> > > > Tel-506-357-9785,Fax-506-357-6010
> > > > hartstv@xxxxxxxxxxx
> > > >
> > > > ----- Original Message -----
> > > > From: "Larry E." <videotech@xxxxxxxxxxxx>
> > > > To: <techassist@xxxxxxxxxxxxx>
> > > > Sent: Thursday, July 24, 2003 8:56 PM
> > > > Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''
> > > >
> > > > > Hi Don, you need to be carefull changing parts in a 169 chassis
with a
> > pa=
> > > > > rts list from a 27" proscan, there are 4 different families of 169
> > chassi=
> > > > > s`s and some of the parts
> > > > > are very different, for example C4108 in your set (family 1) is
> > supposed =
> > > > > to be a
> > > > > 47uf @ 50 volts but in a family 4 169 it`s a 39uf @ 100v,  BIG
> > difference=
> > > > > =2E
> > > > > The usual cause of pin 16 on U4101 fluctuating up and down is the
3
> > caps =
> > > > > you changed, or U4101 is bad check the values, C4102=3D 2.2 @ 100v
> > C410=
> > > > > 4=3D 4.7 @ 100v(not 47uf)  C4108=3D 47uf @ 50v. If those are good
then
> > th=
> > > > > e set is either in ovp or ocp You should have the following in
standby
> > (s=
> > > > > et plugged in but not turned on), Raw B+ on C of Q4101 =3D approx.
165
> > vo=
> > > > > lts, Regulated B+ on C of HOT=3D approx.144 volts, 5v standby on E
of
> > Q46=
> > > > > 01. If the above are correct, check voltage on pin 3 of U4101, it
> > shouldn=
> > > > > `t be above .6v (point 6 volts) if it is the
> > > > > set is going into ocp shutdown. Let me know the results of these
> > measurem=
> > > > > ents,
> > > > > I don`t have a scanner but I do have the schematics and 169
> > troubleshooti=
> > > > > ng guide.
> > > > > Remember that a lot of the capacitor values are different for the
> > various=
> > > > >  169 models
> > > > > so be careful to replace what you pull out with the same value,
Larry
> > E
> > > > > Larry Eastman
> > > > > American TV & Electronics
> > > > > Crystal River, Fl. 34428
> > > > > 352-795-0124
> > > > > pulling out
> > > > > hartstv@xxxxxxxxxxx wrote:
> > > > >
> > > > > > This direct view 32'' unit has me baffeled.Orginally came in
with
> > the H=
> > > > > OT shorted.Replaced with an OEM 2SD1885.Everything else was ok so
> > fired i=
> > > > > t up.The HV was 38.5KV,too hi,so took the chass out to bench
> > test.Turned =
> > > > > it on without a yoke plugged in & I think that's when my problems
> > started=
> > > > > =2EQ4802 smoked in the pin cct.Replaced it & plugged a yoke to the
> > set.No=
> > > > > w my smps won't start.Pin 16 reads 8.5vdc then slowly goes up to
> > 10.5vdc =
> > > > > & then starts going back down to 8.5v.So changed all the normal
parts
> > for=
> > > > >  this smps,ie,the U4101,C4102,4,8,Q4101.Did not help.Replaced the
> > infamou=
> > > > > s CR4118.Checked or replaced both LM311 in the vert & pin cct;also
> > C4403,=
> > > > > CR4401,CR4402.Again no go.Checked or replaced all trans in the PWM
> > cct,Q4=
> > > > > 405,6,7,8,9.Same results;the regulator is trying to start but
keeps
> > going=
> > > > >  up/down from 8.5v to 10.5v.Raw B+ is solid at 165vdc,no
ripple.All
> > these=
> > > > >  tests were done with HOT collector lifted.I have checked all my
tips
> > for=
> > > > >  this unit,& I know there's a ton of them but
> > > > > >   can't find the problem.I have changed so many parts too
numereous
> > to =
> > > > > mention,ie caps,diodes,transistors but I'm stumped.Any assistance
> > would b=
> > > > > e greatly appreciated or if someone would be so kind to email a
pdf
> > for t=
> > > > > his brute.The only print I have is a profax for the 27'' set.BTY i
> > also c=
> > > > > hecked all transistors in the Q4300 & Q4700
> > series.........TIA...........=
> > > > > =2E
> > > > > > Don of HARTS-TVCR-ASC
> > > > > > 9 Robert St,Oromocto,NB,Canada,E2V3N2
> > > > > > Tel-506-357-9785,Fax-506-357-6010
> > > > > > hartstv@xxxxxxxxxxx
> > > > > >
> > > > > >
> > ***********************************************************************=
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