[TechAssist] Re: PTV835 multiple problems
- From: "Tiberio Moreira" <tibstv@xxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Sat, 11 Dec 2004 21:28:32 -0500
some notes i found
bad Opto-Coupler 7412 and Controller 7402. They regulate B+ voltage.
Symptoms range from dead set to picture shrinking to a blob of a picture on
the screen.
phillips ptv835 set projo convergence problem and pincushion
Tiberio Moreira
412 Lancaster St.
Leominster Ma. (978) 5375973
#9176
>From: "Robert Father" <rfather@xxxxxxxxxxxx>
>Reply-To: techassist@xxxxxxxxxxxxx
>To: "techassist@xxxxxxxxxxxxx" <techassist@xxxxxxxxxxxxx>
>Subject: [TechAssist] PTV835 multiple problems
>Date: Sat, 11 Dec 2004 16:42:39 -0500 (Eastern Standard Time)
>
>HI Techs,
> I've been working on a Phillips/Magnavox projection TV. I hope that
>someone has seen one of these problems. The screen has a four-way
>pincushion. The screen shrinks into the middle then back for a second. This
>repeats continuously. Is this possibly caused by the opto coupler (7412
>location) and or the controller (7402 location)?
>
> Problem 2 may be directly related to problem 1. The blue does not
>converge. I replaced the 2 stk392-110 chips. That did not help. I located a
>open protector (1007) on the convergence board. I replaced caps 2052 and
>2055 (.1mf mylar caps). The protector keeps blowing.
>
>I would appreciate any guidance on this matter. Thanks in advance.
>
>Bob Father
>Electronics Specialist
>Albany, New York
>rfather@xxxxxxxxxxxx
>robert@xxxxxxxxxxxxx
>
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