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Sanyo DP32746 Sudden loss of picture    
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retengr



Joined: 16 Feb 2014
Posts: 3
Location: America's Dairyland

PostPosted: Sun Feb 16, 2014 11:55 am    Post subject: Sanyo DP32746 Sudden loss of picture Reply with quote

Research and reading led me to believe this was a mainboard issue, alas, installed a reman mainboard and issue persists. Tv turns on but after about 15 seconds, the picture disappears vey quickly, right to left. Image at left side of screen takes about 4-5 seconds to completely go to black. Happens on all inputs, every time tv is turned on. Backlights NEVER so much as flicker, they always stay on when power is on.. Is this an issue of the power supply not supplying to the mainboard? Mainboard looks fine, no blown caps or burnt spots. Or is it the t-con?
Thanks
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JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Sun Feb 16, 2014 12:12 pm    Post subject: Reply with quote

I'll vote ... Tcon (or panel).
retengr



Joined: 16 Feb 2014
Posts: 3
Location: America's Dairyland

PostPosted: Sun Feb 16, 2014 12:40 pm    Post subject: Sanyo DP32746 Reply with quote

JTS1957 wrote:
I'll vote ... Tcon (or panel).


Picture is fine (when it's on), what's your reasoning for voting Tcon?
JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Sun Feb 16, 2014 1:30 pm    Post subject: Reply with quote

You've already swapped mainboard and eliminated (at least in your own mind) inverter/CCFL bulbs, so when you mention 'no blown caps or burn spots' I have to presume you are talking about on the PS. I also presume you've measured the PS voltages and checked R678/joints.

IF with either motherboard the unit exhibits the same symptom, I would assume that both are O.K., which would tend to point towards tcon or panel (that board that is attached between TFT and tcon and is non-removable/replaceable).

You didn't mention if OSD is affected.
retengr



Joined: 16 Feb 2014
Posts: 3
Location: America's Dairyland

PostPosted: Sun Feb 16, 2014 5:50 pm    Post subject: sanyo DP32746 Reply with quote

OSD does not display after picture is lost. Are the backlight inverters a possible cause? R678/joints? Google was no help. I have not yet checked the PS output.
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JTS1957



Joined: 21 Jan 2009
Posts: 2286
Location: Far, Far Away

PostPosted: Sun Feb 16, 2014 6:18 pm    Post subject: Reply with quote

retengr wrote:
Tv turns on but after about 15 seconds, the picture disappears vey quickly, right to left. Image at left side of screen takes about 4-5 seconds to completely go to black.

You have between 5 and 15 seconds to find out about OSD each time you turn set on.

retengr wrote:
Backlights NEVER so much as flicker, they always stay on when power is on..

Monitor backlight enable - as it changes, lights should go on/off.

R678 can either fail itself or develop bad solder joint(s), usually symptom is 'tv dead', so probably is not the cause of your failure.
Check voltage(s) and see if they come & go as picture does.
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