Re: 2N7002 Questions
Sorry I have not been around for the last few days. Ill follow up with explaining everything this evening. Thanks for the input.
dodadew
Member
Last Activity: 09-05-2021, 04:10 AM
Joined: 04-27-2014
Location: Wisconsin
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Re: 2N7002 Questions
I'm actually using them to signal another device. Both are on separate circuits but they need to signal +12 and -12. In a nutshell this circuit powers up, waits 6 seconds, goes high on pb1, waits 500ms, goes high on pb0, waits 1s, goes low on pb0, waits 1s, goes high on pb0, waits 500ms and goes low on pb1.
Since I need 12v signal I am switching the fet to to get this. No motor drive. . Pb0 is signaling -12 and pb1 needs to signal +12. The -12 side works perfectly. I just need a way to signal +12 from a sot-23 package. That's where I'm stumped....Last edited by dodadew; 02-20-2015, 04:47 AM.Leave a comment:
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Re: 2N7002 Questions
This circuit basically sends a few pulses quick (~ 5 seconds of off and on) then shuts down (~10 microamps). I was going to use some sort of 5v regulator, but to keep cost down and mainly size (final product is less than .5in x .5in) but with the tiny current pull, the resistor kept the ATTINY within operating voltage. The q1 side works perfect. Right after I posted I noticed q2 was not doing what I wanted. I don't know where my brain was. I think what I need to use is a P channel instead to get the functionality that I want. Does that sound like English, because...Last edited by dodadew; 02-19-2015, 11:57 PM.Leave a comment:
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2N7002 Questions
I have a dilemma. I am building a circuit to switch 2 separate "loads"...one with a switched ground and one with a switched positive. I am using an ATTINY to switch a pair of 2n7002 Mosfets. I have attached a schematic. I am using a resistor to step down the voltage from +12 to ~ 4v to run the ATTINY. The question I have is if Q2 would run consistently in this setup or if you have a better idea of what to run? I am using the 2n7002 to sink < 1 amp in both directions. Ultimately I have another circuit monitoring the output of these pins checking for -12 on one and +12 on the other....Last edited by dodadew; 02-19-2015, 11:42 PM. -
Re: Insignia NS-P501Q-10A Power/Clicking Issues
Forgot to answer this before... I used my Fluke 177 set to capacitance....Leave a comment:
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Re: Insignia NS-P501Q-10A Power/Clicking Issues
Here is another picture. The whole screen is distorted just like above....Leave a comment:
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Re: Insignia NS-P501Q-10A Power/Clicking Issues
Well I finally got around to replacing the shorted RJP30E2 transistors. Now the set turns on...sound works (no startup sound but I don't know if this model has that)... so that is progress. Now I move on to...what causes the problems shown in the attached picture I rechecked my VS and VA and both are correctly in range. When I disconnect LVDS and jumper on the control board...i get test screens but the picture still does the same thing. Has anyone seen anything like this before?...Last edited by dodadew; 02-03-2015, 12:58 AM.Leave a comment:
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Re: Insignia NS-P501Q-10A Power/Clicking Issues
I would just replace the board, but I can't seem to track one down anywhere. I saw that a few of them popped up on ebay over the last few months. Now I just have to wait for another one to show. And hope it's not already fried. That's why I'm going through the trouble of repairing this one. Or trying to.
I don't have any more shorts on the board... So maybe I'll just replace them and hope for the best. Before that I'll check everywhere else for shorts.Leave a comment:
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Re: Insignia NS-P501Q-10A Power/Clicking Issues
Well I pulled a few transistors from the shorted X-Main and tested them out of circuit...dead short on 4 of 4 of them. Part RJP30E2. No more shorts on the board with them out. As I can not find this board anywhere now, I guess I will the parts to my cap order and hope I don't toast the new ones putting them back in. Is there anything I could test to see what caused them to die...or do you think it's just the heat / old age that got them.Leave a comment:
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Re: Insignia NS-P501Q-10A Power/Clicking Issues
I understand what bad caps do. I intend to replace all those bloody samwha caps. I am glad that I was able to at least test the power supply with nothing connected to get the readings seeing that the voltages were correct. Now I can cross that one off the list. (other than replacing the caps).Leave a comment:
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Re: Insignia NS-P501Q-10A Power/Clicking Issues
I pulled the X-Main and metered some of it. I do have a short somewhere on the right hand side of the board. Any tips on how to pinpoint it rather than desolder until I find it? If I meter across any of the transistors or the 4 large caps I get a dead short.
I cant find the board to just replace it and would rather fix it than replace it.
I did test the power supply with PS to GND and VS to 5 thru a resistor and it turned on and the voltages stayed up and were right where they needed to be. Also with the X-Main unplugged...Leave a comment:
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Insignia NS-P501Q-10A Power/Clicking Issues
Well I am at it again. Got a new one that I am looking for some insight into. I have read a few other threads but reallly dont want to throw money at this set replacing random boards when I just cant seem to figure out which one it is. Heres what I have
When plugged in, I hear a relay click (turn on), then 4 lighter clicks, then another louder click (shutting off). During this time, the LED on the logic board lights up, blinks off and then stays on until the final loud click of the relay.
Voltages with everything plugged in are:
Va (should be 55) is @ 27 (pulsing with...Last edited by dodadew; 01-12-2015, 02:40 AM. -
Re: Samsung LN52A530P1FXZA Tab bonding repair
I did not pay anything for those 3. They were free... Other than gas to get them. I "fixed" both Samsungs. Had tab issues on each. Sold off real cheap to a friend and let him know it's not a real fix but they work for now and maybe a long time. I figured worst case if I could not fix tab I had a good tcon /main / PS in each to eBay.Leave a comment:
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Re: Samsung LN52A530P1FXZA Tab bonding repair
Just picked up a Samsung LN40A630M1F with the same problems. Found out it was the left most tab @ the chip. Put on a pad I pulled from a cracked screen plasma. All is well now. We'll give it the kid test and see if it lasts a weekend.
Thanks for the insight budm. That's 2 sets you helped me save from the trash.
Actually, I picked up 3 LCDs from a guy that tried to fix them all. He thought this one was a bad T-Con and put a new one in, but had same problems. My new problem is he lost virtually every screw and...Leave a comment:
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Re: Vizio VO420E - No Video But Has Backlight,Sound.
Thanks to you too... It was not getting power....Leave a comment:
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Re: Vizio VO420E - No Video But Has Backlight,Sound.
That's how I found out about the site... Hopefully Google quickly indexes it. I checked my other TV... Same model and same board... So when that one breaks down I can fix it too. Hopefully it won't.Leave a comment:
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Re: Vizio VO420E - No Video But Has Backlight,Sound.
Well, I have a new problem...I put it all back together and started a movie in it...this was on the kitchen counter. Now the problem is that I cant peel my kids away from it. Dont see any noise in the picture...and I am also glad it was not an LCD problem. This fix was much cheaper than a new mainboard, and for the $30 I have into it I think it was a great find....Leave a comment:
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Re: Vizio VO420E - No Video But Has Backlight,Sound.
I will just jump it and give it a few days of use to see if I get any noise in the picture...if I do at the point...I will grab a few different beads and give them each a try. They sure don't make it easy to find a value on them.
Thanks so much for your help...I am positive I would not have been able to single out one little SMD bead in this whole board without your guidance. At least I can say I do know how to solder SMD parts so you wont be hearing from me if I had accidentally lifted a trace or pulled off a...Leave a comment:
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Re: Vizio VO420E - No Video But Has Backlight,Sound.
I was off on my numbers...I guess I read them upside down or am dislexic or something...but Backlight on 0.33a and VIzio logo / blue screen .57aLeave a comment:
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Re: Vizio VO420E - No Video But Has Backlight,Sound.
Progress. I get 0.52amps immediatley after the backlight turns on ...displaying the vizio logo!!!...and I when it goes to the cherished blue screen, I get 0.78a. When I remove the probe from L57 with the set on...I lose video, and I assume the processor resets as the backlight turns off then back on. Should I get a reading with a video source / white screen as well?Leave a comment:
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