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

  • From: "becyn" <becyn@xxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Mon, 11 Oct 2004 11:46:15 -0400

real tuner problems can be a challange with all those smd's!
It wasn't clear from your post whether 2-6, etc were the good or the bad
channels. However missing whole spans like that indicates a "band" issue.
The amp IC that Max allued to is a good bet. The other (cringe) possibility
is leaky SMD varactor diodes in the affected band area.

Cable channel 14 is actually between ch2 and 3, so if you are missing lo
band, the begining of the cable spectrum will be missing as as well.

Jim McVey
McVey Alltronix
327 Broadway
Newburgh N.Y. 12550

Factory authorized
service for over 20
major brands.
845 561 8383
----- Original Message ----- 
From: "Old TV Man" <mebonnell@xxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Sunday, October 10, 2004 3:53 PM
Subject: [TechAssist] RCA, G27304DT, CTC177AM2, Tuner problem


> I believe the IC Al is talking about is U7301 RCA part # 215532
> (CXA1594L).
> I have changed several of those myself.
>
> Max Bonnell
> Bonnell TV
> Robinson, IL
>
> Sender: techassist-bounce@xxxxxxxxxxxxx From: ampm@xxxxxxx(al=A0m) Date:
> Sun, Oct 10, 2004, 2:57pm (CDT+1) To: techassist@xxxxxxxxxxxxx Subject:
> [TechAssist] Re: RCA, G27304DT, CTC177AM2, Tuner problem Reply=A0to:
> techassist@xxxxxxxxxxxxx
>
> Just had one like that changing the IC that is on top of the board in
> the tuner solved the problem. Sorry I don't remember the IC # but you
> should know which one I am talking about.
>
> Al Marquardt
> ampm@xxxxxxx
> Al Marquardt Electronic Repair
> 206 W Main
> Girardville Pa. 17935
>
> ----- Original Message ----- 
> From: <daryls_tv@xxxxxxx>
> To: <TechAssist@xxxxxxxxxxxxx>
> Sent: Sunday, October 10, 2004 2:42 PM
> 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
> 2402 Wyoming Ave.
> El Paso, TX 79903
> 915-565-9184 Voice/Fax
> daryls_tv@xxxxxxx
> www.angelfire.com/tv2/daryls_tv
> --
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