[TechAssist] Re: Panasonic CT32G5B Squealing power supply
- From: MDileo0000@xxxxxxx
- To: techassist@xxxxxxxxxxxxx
- Date: Fri, 16 May 2003 18:25:36 EDT
After installing the correct regulator for IC803, I still had a squealing
power supply that would not come up to 130VDC nominal. Disconnecting
secondary supplies, one at a time, isolated the last problem to a shorted to
ground D830, 1/2wt 27 volt zener on the 19 volt line which supplies voltage
for the audio circuit. This set had been hit by overvoltage caused by the
power company line crew working the neighborhood. Thanks to all for their
professional input.
Dominic Di Leo
Atlantic TV
Freeport, Maine
__________________________________________________
Panasonic CT32G5B, ABP331 chassis.
This set came in with a shorted avalanche diode D525, damaged power
regulator IC803 (STR58041) and open resister R828 (47@3wt). It squeals as if
there is a secondary short. Scoping the regulator circuit shows good initial
peak-to-peak ringing that dies off as if the circuit is starving from
insufficient current. I would like to know if anyone has a method to run this
circuit fully decoupled from the chassis? I already tried disconnecting all
of the secondary loads and using a 50 watt lightbulb as a dummy load for the
130 volt supply. I have a factory manual and it lists the regulator as being
a STR58041A but there was a STR58041 installed as original factory and it has
better operating specs than does the "A" version. Any ideas or past
experiences appreciated.
Dominic DiLeo
Atlantic TV
Freeport, Maine
_____________________________________________________________
In my experience with Panasonic sets the STR58041 will not work in place of
the original STR58041A. The STR58041A is identified by a white dot after the
STR and does not have the letter A at all. The white dot is where the * is
in this example, STR*58041. The Panasonic P/N is C5HABZZ00062. There is a
very good article in "The Speaker" if you can find it. The article gives the
different resistance readings pin to pin of the two versions and explains
why they are not interchangeable.
**************************************************
Jim Myers
Since 1972
Telrad Electronic Services Co.
Fort Wayne, IN 46815
*************************************************
You MUST us the "A" version if that is what it calls for, there is a
difference, the plain version will not work for an "A" version, I don't
know about the other way around. The "A" is not at the end of the
number as you would suspect (that would be too easy). It is at the end
of the next line of numbers under the part number and may be smaller
print than the part number but it is important. John.
John Mielke
Main TV
Longmont, Co
maintv@xxxxxxxxxxx
*****************************************************************************
The Tech Address Book:
http://www.tech-assist.org/secure/tip/contact.html
Add a Repair Tip Here, or Change/Remove your Email Address:
http://www.tech-assist.org/secure/tip/main.html
Lost Password:
http://www.tech-assist.org and select "Lost your Login Info?".
Email Archives:
//www.freelists.org/archives/techassist/
Other related posts:
