[TechAssist] Re: VS4551 mitsubishi ,no power up when cold: only thump-thump. still not fixed
- From: Jim Myers <jr.myers@xxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Sat, 05 Mar 2005 11:53:01 -0500
Sent a PDF to your email Phil, sounds like the fix you need.
********************************
Since 1972 *
Jim Myers *
Telrad Electronics *
Fort Wayne Indiana *
********************************
Phil Bader wrote:
> ARRRRG! I watched this set an hour last night, unplugged it, went home.
> This morning, again, plugged it in cold, pushed power: "Thump-Thump..."
> Same crappola.
> I immediately unplugged it, removed back, removed two screws holding the
> chassis frame in. Plugged it in, powered it up perfectly.Then I flexed,
> tapped,etc.No effect. I am still not sure if this is a borderline cap
> discharging overnight and cooling(bad ESR) or some bad connection. I'm
> stumped. I KNOW the cap i replaced last night was bad (see thread below).
> Phil Bader
>
>
> FIX?
> I may have fixed the start up problem. I first replaced IC9A1 , an SE130
> regulator.
> But I then ESRd caps all over. I came across one cap soldered to the
> bottom of the board to 5 pin regulator,IC9A2 (looked like soldered to
> pins 1,2) It was a 4.7mfd@50V. It was totally open.
> I replaced it.
> Unit came right up with good picture.. Tomorrow morning will be the test
> for the cold start.
> Phil Bader
>
> Phil Bader wrote:
>
>
>>The fix for the "arcing" vertical distortion was not the yoke
>>connection, but many cold solder joints on main board, especially the
>>board yoke plugs. Can't believe I missed them all. Resoldered, fixed.
>>I came in this morning, and the TV being cold and unplugged all night,
>>pushed power and I only heard a once per second "thump-thump-thump"
>>noise. We feel this may be one of the PS electrolytics with hi ESR, and
>>when cold, does this but if warms up, runs OK.
>>Anyone have any specific tech tip on this model for this???
>>This will be #3 repair to get this out the door!
>>Phil Bader
>>
>>This played two days OK. Then the vertical distorted like arcing,
>>pull-up, lines stretched,bowed etc.
>>I did resolder the vert output IC. If I hit the side of the setwhile
>>happening it cleared.
>>I saw somewhere in a fix email,was to solder the yoke pin.Sounded like
>>they meant actually at the yoke (as opposed to on the board) I quote:
>>
>>"Cure: Found bad solder connection at connector on red yoke. Reason for no
>>deflection is these connector run in seres to the other two CRT's."
>>Anyone care to clarify this?
>>Phil Bader
>>
>>
>>
>>
>>
>
>
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