Got this unit in today totally dead but when i removed connector (cn701)the lamps came on momentarily and if you put it half on lamps all come on.Power supply seems to work fine.All 24vdc present on cn903 and all on cn902 except on/off .43vdc and dim 0vdc.The trouble points towards main board as the metal cover/heat sink in middle of board is quite hot to touch.All voltages on cn701 except pwr and bl_on and bl_br.Voltages present to ir sensor and buttons.
Insignia 32" NS-32E740A12
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by cajoegHello, I'm new to the group and to trying to repair a LCD TV. During the past few years, I've been collecting/repairing/restoring vintage personal computers (Commodore, Apple II, Atari, TRS-80, Texas Instruments, and Timex Sinclair). This has been my retirement hobby. Now I've gotten interested in trying to repair a LCD TV that I have and used regularly when working on vintage computers.
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by valvashonHaving a new problem with the 19" Insignia that I modified with one of my automatic turn on circuits. That is now completely disconnected so that is not the issue. I was doing some modifications on that circuitry and managed to short something out on the underside of the power board.
Actually found and bought the service manual (who knew it was even available?!) which brought me to the High Voltage Startup Circuit controller chip.
Looking up that chip number- LD7575APS brought me to the attached datasheet. I have marked my voltage readings on the schematic sheet (open in new... -
by howardc64Eventually discovered a burn mark near lower corner of LCD. Here is a summary
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07-11-2025, 04:04 PM -
by angelosHi Guys,
It's been a while that i have been active on the forum, sorry for that. My primary job has been keeping me quite busy.
The above set starts up with sound working just fine but the CCFL lamps (Inverter) runs for one second and switches off.
My 24V supply is steady and the ON/OFF pin to the inverter is at +5V.
The only thing i see is the PWM signal pin is at +5V without any square wave being emitted. Is this normal? as far as i can remember there needs to be a square wave pulse there. Am i right?
I will now measure with my oscilloscope probe on... -
by arnardI have a weird backlight issue on the above Insignia Plasma that I am coming up empty on researching.
The display is darker on the left than on the right side of the screen. It uses 4 U shaped plasma tubes. I have had it apart deep enough to tell you that the tubes are bright as they should be at the electrode ends but dim as they get to and go around the bend.
Since it is all 4 tubes it seems like it would be an inverter/backlight board but obviously can't be a blown up component as it does still somewhat work. I'm thinking low voltage but no idea where to go beyond...06-10-2023, 01:36 AM - Loading...
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