[TechAssist] Re: VS4551 mitsubishi ,no power up when cold: only thump-thump. still not fixed
- From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Sat, 05 Mar 2005 11:36:57 -0500
yes.Used spray.
This I think is several possibilities:
One, a weak part(probably a cap) is actually /discharging over night/
being unplugged (rather than coolingdown.)
Once it has been tried the next morning, it gets charged up and will
soon work all day.Cooling sprays would be no help here.
Second possibility is temperature of a borderline part /cooling overnight./
Third: a /hairline crack/ in a trace,solder connection,etc, thru
/expansion/contraction overnight/ affects it.
I flex, tap,etc while on and get no reaction. I have freeze sprayed
while on the caps and some reg ICs to no avail. The real test is always
overnight unplugged. I was thinking of /leaving it plugged in/ but
turned off this weekend to test my charge-up/discharge cap theory: Is a
part discharging, or cooling off.
Phil
al m wrote:
>Phil did you try to use freeze spray?
>Al Marquardt
>ampm@xxxxxxx
>Al Marquardt Electronic Repair
>206 W Main
>Girardville Pa. 17935
>----- Original Message -----
>From: "Phil Bader" <tjanphyl@xxxxxxxxxxxxxxx>
>To: <techassist@xxxxxxxxxxxxx>
>Sent: Saturday, March 05, 2005 10:54 AM
>Subject: [TechAssist] VS4551 mitsubishi ,no power up when cold: only
>thump-thump. still not fixed
>
>
>
>
>>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
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>--
>>
>>Philip Bader
>>Jan Phyl TV Inc. (estab. 1976)
>>3420 Recker Hwy. Winter Haven, Fl. 33880
>>Fax (863) 299-8821
>>email: tjanphyl@xxxxxxxxxxxxxxx
>>
>>
>>
>>
>>--
>>
>>Philip Bader
>>Jan Phyl TV Inc. (estab. 1976)
>>3420 Recker Hwy. Winter Haven, Fl. 33880
>>Fax (863) 299-8821
>>email: tjanphyl@xxxxxxxxxxxxxxx
>>
>>
>>
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--
Philip Bader
Jan Phyl TV Inc. (estab. 1976)
3420 Recker Hwy. Winter Haven, Fl. 33880
Fax (863) 299-8821
email: tjanphyl@xxxxxxxxxxxxxxx
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