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#1 |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 9
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![]() I am trying to fix my Dynex tv. The PSB is new and so is the Control Board, but when I turn it on, I get "please wait..." on screen, then it quickly goes black. I have the back of it off and checking voltages shows 5v standby and 2.5v supply comes on going away/into PSB/Control Board, 24v is present on PSB (getting .4v on most, if not all, backlight lines, 5v to backlight is there also), the control board's heatsink staying hot to the touch, plus the 2.5v going away/into the PSB/Control Board, gives me the impression it is on. What else should I check for?
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#2 |
Badcaps Veteran
Join Date: Jan 2013
City & State: midwest
My Country: U.S.
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![]() post good clear straight on pictures of each board and one of the whole back as to see how everything is connected, use the go advanced to post pics.
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#3 |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 9
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![]() Got it, will do.
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#4 |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
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Posts: 9
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![]() Pics of the connections and boards. I can check specific voltages if asked to. I have also checked for the voltages I get on the top two backlight lines when I power on and it reads about 12v for each before the backlight turns off. I know that it technically works other than it saying "please wait..." before the screen just goes black with no more backlight while everything stays in the "powered on" state.
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#5 |
Badcaps Veteran
Join Date: Jan 2013
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![]() ok start with connector x508, put your black probe on chassis ground, red probe on each pin, just probe the top to touch the metal, check each pin in standby (tv plugged in power off) take note of voltage, keep the probe where it is power tv on take note, report results, like pin 1 power-on, standby 0 volts powered on 3.3 volts, need pin label and condition in both standby and powered. Do that for each pin.
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#6 |
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![]() good example of testing there: https://www.youtube.com/watch?v=XH9GfkGQX1I
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#7 | |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
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![]() Quote:
Standby mode plugged in and powered off: pin 1: 0.000v pin 2: 0.033v pin 3: 0.033v pin 4: 0.000v pin 5: 0.000v pin 6: 0.020v pin 7: 0.002v pin 8: 5.079v pin 9: 0.001v pin 10: 0.005v Powered on mode: pin 1: -0.005v pin 2: 11.78v pin 3: 11.78v pin 4: -0.007v pin 5: -0.007v pin 6: 2.482v pin 7: 5.000v pin 8: 5.057v pin 9: 2.535v pin 10: 4.570v |
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#8 | |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
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![]() Quote:
pin 2: Labeled "12v" pin 3: Labeled "12v" pin 4: Labeled "GND" pin 5: Labeled "GND" pin 6: Labeled "PON" pin 7: Labeled "5v-1" pin 8: Labeled "5v-5" pin 9: Labeled "PWM" pin 10: Labeled "BON" |
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#9 |
Leaking Member
Join Date: Dec 2014
City & State: Atlantic Canada
My Country: Canada
Line Voltage: Ground, 0Hz
I'm a: Hobbyist Tech
Posts: 5,218
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![]() So BLon is 5v but the backlights are off? That means you got bad backlights!
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#10 | |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
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![]() Quote:
Bad caps, possibly? ((I also noted that this is a "new-probably refurbished or taken from partly good tvs respectively" PSB and Control Board. So, I am not sure that is what the issue is. Unless there is a bad cap on another pcb behind the metal housing that everything is attached to (which I doubt, but who knows), maybe in between the metal and backlight panel where the wires go into it)) |
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#11 | |
New Member
Join Date: Dec 2018
City & State: Rosamond
My Country: United States
Line Voltage: 120VAC 60Hz
I'm a: Knowledge Seeker
Posts: 9
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![]() Quote:
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#12 |
Badcaps Veteran
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![]() ok, so you didn't waste any time and stripped it down, shows you're not lazy,
![]() https://www.youtube.com/watch?v=vNIWtrEHYsc |
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#13 | |
New Member
Join Date: Dec 2018
City & State: Rosamond
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![]() Quote:
![]() ![]() I still checked the coils and they seemed ok, all reading about 0.1-0.2 ohms. However, it looks like this repair is a bust, as I don't think I will be able to find a bulb like the one that is needed. I am curious to see if the bulbs could just be replaced with LED's instead, but I am not sure if that would be a viable option, at least not without figuring out a way to drive them... |
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#14 |
Badcaps Veteran
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![]() it can be converted to led pretty cheaply, aliexpress sells kits for not much, probably ebay too.
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#15 |
Badcaps Veteran
Join Date: Jan 2013
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![]() I meant to say ebay has them too but not as much to choose from as aliexpess.
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