[TechAssist] Re: GE 31GT658 chassis CTC187CK regulation

Leonard, If you used a generic STK, then that would be suspect. If OEM, I
would look elsewhere.

There are a couple of filter capacitors in the power supply that will affect
regulation. They are small, I would suggest that you just change them.

Paul W
C&W Electronics
Azle Texas


----- Original Message -----
From: "Leonard G. Caillouet" <lcaillo@xxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, February 27, 2003 10:25 AM
Subject: [TechAssist] GE 31GT658 chassis CTC187CK regulation


>
> Replaced the HOT, CR4106P (B+ rectifier Part # 243636), U4101V
(STK730-030)
> and line fuse.  Now the set runs but regulated B+ is 145.5 Vdc.  It
appears
> to have a little trouble regulating on scene changes.  Have checked all
> components related to the regulator and found only R4105 was off by a
couple
> of ohms, so I replaced it with no effect.  I am thinking that I have a bad
> regulator IC but just want to check to see if anyone has run into this
> before or is anyone is more  familiar with this circuit than I am (which
I'm
> sure is the case).  I am working with Bob Rose's book and do not have the
> Thompson service literature on this chassis, so if anyone can fill in the
> blanks I'd appreciate it.
>
> Pin 1 is -40.7 Vdc which is within the range it should be.  This means
that
> the error amp in the chip is keeping the voltage at the reference level,
so
> I assume the chip is just bad.  Am I missing something or is the voltage
at
> pin 2 too far off?
> Pin 2 is -30.5 Vdc, I am not sure what it should be.
> Ground is good at pin 3
> Pin 7 is -.5 Vdc  I thought this should be more negative but not sure.
> Pins 11&12 are 145.5 Vdc
>
> The HOT does not seem to be getting very hot but I am not running it for
> very long before shutting it down.
>
> Thanks
>
> Leonard G. Caillouet
> Service Manager
> Electronics World
> Gainesville, FL
> 352-332-5608
> 352-332-5668 (fax)
>
>
>
****************************************************************************
*
> Submit A Repair Tip Here, or Change/Remove your Email Address:
>         http://www.tech-assist.org/secure/tip/main.html
>
****************************************************************************
*
> For automatic password retrieval 24 hours a day, go to:
> http://www.tech-assist.org  and select "Lost your Login Info?".
>
****************************************************************************
*
>
*****************************************************************************
Submit A Repair Tip Here, or Change/Remove your Email Address:
        http://www.tech-assist.org/secure/tip/main.html
*****************************************************************************
For automatic password retrieval 24 hours a day, go to:
http://www.tech-assist.org  and select "Lost your Login Info?".
*****************************************************************************

Other related posts: