Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
The trouble is where jt was originally when I first posted. I'm getting 6v at the 13v, 11v at 21v when forced on. I know its confusing because of getting the higher voltages, but it was temporary. I don't understand why it started working, and then why it stopped.
Hazen
Member
Last Activity: 06-15-2020, 07:00 PM
Joined: 11-11-2016
Location: Tulsa, ok
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
Only during that one occurance. After I checked the voltages and state change of Q653 from post #24, I then started to notice the second click when I forced PS-ON. I started checking the voltages and found I was getting +13V and +21V, but again, only during that one instance. The 13v and 21v are no longer there when PS-ON, and I haven't been able to recreate the scenario to get them back....Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
yes I am forcing it with the 1k resistor, but it was the first time seeing it switch to the higher voltages.Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
Yes, they are stable at the lower voltages, other than the 3.3v, it is at 3v.
That was the first time that I have seen it switch, and now I haven't been able to get it to do it again.
Where is the standby voltage produced? Since it's 3.3v, does it go through a switch? Once I connected the ps board to the tv, I got the standby light. Also, when I power on the ps I hear one slight click, when I was getting the correct voltages, I would...Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
Ok, well something unexpected happened. After I posted about checking Q653 and toggling ps-on about 10 times to see the state change, I started checking other areas for voltages, and for some reason, I started getting the voltages I expect. I saw 21v at p-on+21v, and 12.8 volts at amp+13v. I connected everything back to the tv and my standby light came on, but would blink. I pressed the power button but it did not power on. But now it has went back to the state that was/is my original issue.
...Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
I do see a state change with ps-on and when it is removed....Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
On Q1704 drain, I have 164v, on Q601 source I have 0v checked when on. I also checked D1603/D1605 and have 164v at that junction.Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
On Q602 the voltages to ground are
pin 1 (gate) 12.7 on/ 11.3 off
pin 2 (drain) 12.5 on/11.1 off
pin 3(source) 11.7 on/10.7 off
voltage g-s 1.8v, d-s 1.7vLast edited by Hazen; 12-04-2016, 03:51 PM.Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
I've removed all the larger components and checked them, and they check ok. The smaller components I've checked in the circuit, and didn't find any shorts. I'm not sure how to check the IC's other that checking voltage readings, and the same with the T601, other than checking the resistence on the differant windings.
I'm getting 11v on IC601 VCC...Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
I have 10v across c616 when its not forced on, and 9v when it is forced on.
Thanks for all the help you are giving me!!Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
I'm getting 8v at IC1601 vcc. Should I be getting around 15.6v?Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
Both D1603 and D1605 have 1.3M with neg on cathode, and 2.2M with pos on cathode. They were tested in the circuit, although I had previously removed them and they checked good. Should I remove them and check the resistance again?Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
With the 1k resistor across P-ON-H2 and AL3.3V I have 160vdc at C605 and C1621. I've checked both mosfets Q1601, and Q1602 out of circuit and both check ok. I get 160vdc at the drain on both also.Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
I've read through the other post and here are my findings so far. I've put a 1k resistor across the 3.3v and p-on-h2, with 2.5v on p-on-h2. I still have only 11v at the p-on+21v, and 6v at the amp+13v. I've jumpered across the 3.3v to the j106/bl-sw with a 1k resistor and the display did not come on. I've checked the voltage at the protect 1 and protect 3 and get <1v on each.
Thanks!Leave a comment:
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Re: Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
Any Ideas?Leave a comment:
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Emerson LF501EM4 s/n ds4 no standby light, and won't power on.
Hello,
I have been troubleshooting this tv for a little while, and now I need some expert help. It was working fine for about 10 minutes one morning and then just went dead, with no standby light. After doing some research, I replaced the main board, which didn't help. I then ordered a replacement ps board, but was shipped a different version than I ordered. I couldn't see any difference between my ps board and the replacement, so I tried it in the tv. The standby light came on, and it would try to turn on, but then the red light would flash a few times. I tried the ps with both... -
Re: New Members - please post your introductions here
Hello,
I can't believe I just now found this forum. Looks like it has many knowledgeable people that can hopefully help me.Leave a comment:
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