[TechAssist] Re: RCA, G27304DT, CTC177AM2, Tuner problem UPDATE

  • From: "Intrepid Video Support" <support@xxxxxxxxxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Tue, 12 Oct 2004 22:18:01 -0400

Daryl,
All I can recommend is remove all the solder from the grounds. Get yourself a 
head-visor magnifier and
look carefully at the tuner area.
As many of these as I have done, I still can find a way to make a solder joint 
or lift a trace.
If all looks OK, resolder.
Now, moving those coils around was not a wise choice.
Good luck.

Jeff
--
Intrepid Video TV/VCR Repair
263 S Front St, Steelton PA 17113
717-939-7708; (F) 717-564-4952
www.intrepid-video.com  www.tech-repair.net
----- Original Message ----- 
From: <daryls_tv@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, October 11, 2004 11:52 PM
Subject: [TechAssist] Re: RCA, G27304DT, CTC177AM2, Tuner problem UPDATE


Another day shot to Hell.....
I spent all day again on this dog.
It was mentioned several times to replace U7301.  This was the first part I 
replaced to no avail.  I
didn't have another new one to try but I had the next best thing.  I had a 
working set to borrow parts
from.  I replaced the IC again but still no change.  Thanks to Barry Thompson 
for the flow chart.  I
followed it out and found nothing wrong.  I compared voltages to the working 
set and didn't find anything
out of line.  I swapped out the varactor diodes without any help as well.  I 
figured I couldn't mess it up
any more than what it was... so I played around with the coils and parameters.  
Now I have some small
gains but still not acceptable.  Channel 2 has lines and motor boating.  Ch. 3 
through 6 is acceptable but
not great.  Ch. 7 through 10 is good.  Ch.11 has no picture and sound, just 
lines.  Ch. 12 through 18 are
good.  Ch. 19 trough 22 are ugly with lines.  Ch. 23 through 39 are great.  Ch. 
40 through 48 has poor
picture with lines and has noise in the sound.  Ch. 49
  & 50 has nothing but motor boating. Ch. 51 up is great until Ch. 99 which has 
lines and a poor picture.
That is the highest channel on the cable system.
I can still place my finger near some of the coils in the tuner and it will 
perk right up.
Any other ideas would be appreciated.
Thanks,
Daryl
Daryl's TV
2402 Wyoming Ave.
El Paso, TX  79903
915-565-9184 Voice/Fax
daryls_tv@xxxxxxx
www.angelfire.com/tv2/daryls_tv

----- Original Message -----
From: daryls_tv@xxxxxxx
Date: Sun, 10 Oct 2004 12:42:56 -0600
To: TechAssist@xxxxxxxxxxxxx
Subject: [TechAssist] RCA, G27304DT, CTC177AM2, Tuner problem

>
> Hi,
> This RCA, model # G27304DT, ch. CTC177AM2, is really kicking my behind.
> It started with the complaint from the customer of losing some channels with 
> lines in the picture.  I
pulled it into the shop and did the usual tuner re-soldering job.  Set looked 
great and was delivered only
to find out it was doing the same thing.  Took it back to the shop where it 
worked great.  I re-soldered
everything again plus all of the connections on the smds.  Delivered it again 
and you guessed it...same
thing.
> The channels from 40 through 50 were either missing or full of lines or motor 
> boating.  I played with
some of the tuner parameters and it seemed to work but not to my satisfaction.  
The customer was pleased,
so I left.  A week later, same thing.
> I pulled it back to the shop where it worked fine.  BTW... the customer has 
> another set that works fine
on the same cable line.  I put an attenuator on my cable line and the trouble 
showed up and even worse.
It gave me channels 2-6, 18-22, and 40-50 with the problems.  I re-soldered 
every smd in the video section
besides the tuner again and all of the grounds in the set... no help.  Looked 
with a high power magnifier
for cracks in the print (none found).  Replaced IC7301, C7414(cracked), 
CR7102(didn't check the same as
the others), Q7102(RF amp), U3201(eeprom), & U1001(t-chip).  Did the tuner 
alignments after each parts
change but still no joy.  I found that if I would place my finger over coils 
L7114 & L7112, the set would
start to function properly.  I got the same effect placing my finger over 
L7115, L7113 & L7111.  I didn't
have to touch the coils, just put my finger near the coils.  This symptom 
reminds me of the old tube days
when the grid neutralizer trimmer cap was
  o
>  ut of adjustment on the RF amp tube.
> I really hope someone has encountered this and has a cure.... Help!!
> Sorry for the long post but I deemed it necessary to explain the problem.
> Thanks,
> Daryl
> Daryl's TV


-----------------------------------------------------------------------------
Lost Password:
http://www.tech-assist.org  and select "Login Problems?".
Email Archives:
//www.freelists.org/archives/techassist/

Other related posts:

  1. Home
  2. techassist
  3. Archive
  4. 10-2004