Re: 50pg20 Power Cycling When Power Applied
I've tried using a small hair drier.. to locate the problem.. nothing seems to change.. although its pretty hot in here.. I live in Florida.. would be nice if I could bring the Tv outside in the cold, but that's not going to happen right now.. Next will be to break out a can of cold spray and start chasing components..
Vladas
Member
Last Activity: 02-24-2013, 05:12 PM
Joined: 12-30-2012
Location: Sarasota, Fl
-
Re: 50pg20 Power Cycling When Power Applied
I would be concerned about my meter if I was using my analog meter.. I'm using a pretty good true RMS meter that has pretty good input protection..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
Television has been on all afternoon with no problems... checked most inputs, HD etc.. all seems fine.. If I turn it off via the remote or the main power switch it will begin to cycle.. if I unplug it when its working and then plug it back later in it turns on immediately (no standby, comes right on)..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
I've read that this precision voltage regulator can be used as a great replacement for a zenor diode.. I may have caused a disruption in biasing..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
Hi, All I did was try to measure the voltage to ground on the 19V primary side of this voltage regulator.. I had the DMM in ohms measurement by mistake instead of DC voltage and the TV went into standby..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
I'm not shorting this voltage regulator when I turn on the TV.. only causing it to go into standby mode so I can turn the TV on at its main power switch.. now, if I turn off this main switch the TV cycles again and wont go into standby.. I can operate the TV after I short it into standby and then turn the TV on.. Then I can turn the TV on and off by unplugging from the AC input..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
OK, Getting somewhere... Now the OK signal from the main board feeds this circuit I believe .. Could this capacitor actually be on this main board or would it still be on the main power supply board? I do have a small 47uf cap near the sub-micon controller chip, Page 38 of start up sequence says "The 5V (standby) voltage is routed to the Sub Micon (U701) on the SMPS and through P803 (The connection between these two boards) to the Main Board for Micon operation ( IC100). AC detect Pin 18 of P803 is generated on the SMPS by monitoring...Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
I replaced the 10uf , 63 volt cap on the primary side of an adjustable high accuracy voltage regulator on this plasma. The cycling problem still continued. I went through the 5 volt standby circuit and when I ohm out the input (19v) side of this regulator (a KA431) when its on, the main board goes into standby and the TV then turns on with the main power switch.. I have to order this regulator from China, very inexpensive.... Is it possible that there is a capacitor in this circuit that is causing this voltage regulator not to bleed down...Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
OK Thanks.. I will pull board and see if I can chase one down... Thanks for all the help once again! VladasLeave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
I will have to pull the board out and look at the traces (NO Schematic) to find primary side of regulator at cap... I know its @19V coming in and 5V coming out..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
Replace four caps in middle of picture (3300uf) and one to right hand side (680uf)... NOT the one on left side (470uf)....Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
I did replace the four 3300uf caps and one 680uf cap on this board the other day... near this voltage regulator circuit... There is a 470uf, 25V near this connector I DID NOT replace...Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
There is a smaller power resistor (.150 at 5W) on the top side of the board I didn't check.. only the three that you mentioned the other day..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
Oh OK... I actually just tried heating up Power supply board near 5V regulator.. Still Cycling..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
12V and 16V is cycling on and off but seem OK , 12.2V and 16.3V... (with warm Control/Main board)Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
I jumped before measuring 12 and 16V... M5V doesn't seem to change upon heating of main board..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
That's a great idea... Now am I looking for 5V on M5V (Board plugged in) with heating of the board?.. Its 3.2V and cycling when plugged in..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
M5V measures 0V with control board (main) unplugged.. Cycling 3.2 volts when plugged in..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
On page 50 #3 of the manual it says that M5V vcc is shorted when cycling is present.. There is no short that I can find..Leave a comment:
-
Re: 50pg20 Power Cycling When Power Applied
No power cycling when Main board is unplugged, though no power to other circuits, other then led on small green control board... When just small green control board is unplugged and main board is connected -still cycles..Leave a comment:
No activity results to display
Leave a comment: