Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 147
Default RCA TV model 20541, chassis CTC203J2 with Excessive Reg B+

Hi,

I have a 20" screen RCA TV model J20541, chassis CTC203J2
(mfg 10/00) in my service shop (no SM).

TV tries to go on, but turns right off due to excessive HV. The
regulated B+ measured +154V which is too high.

I tested some parts in the voltage regulator circuit, but without a
schematic, I am "handicapped".

Did anyone fix a similar problem with this or similar chassis TV?

Thanks in advance, Brad

Before you type your password, credit card number, etc.,
be sure there is no active keystroke logger (spyware) in your PC.

  #2   Report Post  
Posted to sci.electronics.repair
external usenet poster
 
Posts: 1,569
Default RCA TV model 20541, chassis CTC203J2 with Excessive Reg B+

On Tue, 07 Oct 2008 14:11:55 GMT, (Brad) put
finger to keyboard and composed:

Hi,

I have a 20" screen RCA TV model J20541, chassis CTC203J2
(mfg 10/00) in my service shop (no SM).

TV tries to go on, but turns right off due to excessive HV. The
regulated B+ measured +154V which is too high.

I tested some parts in the voltage regulator circuit, but without a
schematic, I am "handicapped".

Did anyone fix a similar problem with this or similar chassis TV?

Thanks in advance, Brad


There is this old thread in the Google Groups archives:
http://groups.google.com/group/sci.e...1d1f36e403d846

It suggests that the fault may be in the feedback circuit on the
secondary side.

There is also the following manual at eserviceinfo.com.

148 page Thompson Consumer Electronics (RCA & GE) technical training
manual for RCA ProScan color TV model # CTC203:
http://www.eserviceinfo.com/download...CA_CTC203.html

I don't know how relevant the above manual is to your chassis, but I
notice that the manual does not specify a value for B+, which suggests
to me that it may vary between versions. Anyway, it looks to me from
the values of R14115 (143K), R14116 (2K), and R14126 (37.4K) that the
B+ in standby mode should be about 190V. In run mode the B+ is about
5% less, ie 181V (= 2.5V x 145K/2K). Your chassis, if it is similar,
may use different resistor values, and a different B+.

If you are seeing a B+ voltage which is about 10V too high in run
mode, then I'd check the +13Vr and +16Vs supply rails. Have you
checked C14101 (2.2uF)?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
32" Sony tv model:KV-32S22,chassis:SCC-K97D-A,chassis:AA-2D [email protected] Electronics Repair 2 February 8th 06 01:55 PM
27" JVC tv model:AV-27BP6,chassis:A47 [email protected] Electronics Repair 0 August 18th 05 02:52 AM
RCA CTC 177BH2, model 27GT613, excessive width and apparent pincushion problem [email protected] Electronics Repair 6 July 27th 05 09:05 PM
JVC TV Model AV-27920 chassis A67 Zarf Electronics Repair 3 July 5th 05 02:38 AM


All times are GMT +1. The time now is 01:53 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"