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

  • From: <hartstv@xxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Sat, 26 Jul 2003 22:46:11 -0300

Larry,that still doesn't make sense;pin16 is vcc for the ic??..Anyway, to
all who helped on this repair tks a bunch & I found the problem.SMD r4150=22
ohm was the culpret.I had checked this little guy & it measured 23.4 ohms
but looked heat stressed so I replaced it with a regular 22 ohm 1/2 watt &
you guessed it ;the power supply came to life,BUT, I'm back to square 1.My
hi volts is 40kv & of course shuts down.When I bench tested this chass,my hi
volts was 30kv using my test yoke.So with the chass in the set I rehook my
test yoke to it & it's 30kv & no shut down.I'm assuming the bonded yoke on
this set is bad,causing the hi volts to go so high[40kv].It shuold be 31.5
for this 32'' unit.Has anyone seen this happen where a bad yoke will cause
the hi voltage to increase.I'm guessing shorted windings in the horz
yoke.Just want to verify my findings on this set before I give the bad news
to my customer.Tks again to all who gave me alot of good info & 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: Saturday, July 26, 2003 6:57 PM
Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''


> Don, it`s a typo, he meant pin 16, Larry E
>
> hartstv@xxxxxxxxxxx wrote:
>
> > Tks for the guide Al;
> > p5 of u4101 is ground.Is this a typo error??
> > 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: "Al Gutz" <alg@xxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Saturday, July 26, 2003 12:42 AM
> > Subject: [TechAssist] Re: RCA-CTC169AM,chass-f31221wn-32''
> >
> > > Don
> > >
> > > Re RCA trouble shooting guide
> > >
> > > 1 check volts at u4101 p5  if > 2.5v IC is in overcurrent shutdown
> > >
> > > 2 Check volts at 4101 p16  if > 15V IC is in overvoltage shutdown
> > >
> > > 3 if p16 is between 10.5 to 15 v IC should operate
> > >
> > > 4 p3 should be < .6V if between .6 to .9 regulator will cycle on & off
> > >
> > > 5  check output of 4101 on P14  clock on P10 & 11
> > >
> > > 6 To check IC remove AC and connect external PS to P16 scope above
> > > points,
> > >   raise voltage to 10.5 volts and IC should begin to operate, do not
> > > exceed 15V, as volts is changed the duty cycle scoped at P14 should
> > > change
> > >
> > >
> > > Al G
> > >
> > > hartstv@xxxxxxxxxxx wrote:
> > > >
> > > > 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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