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LYNX 2 On/Off Problems Need Help


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#1 sub2001zero OFFLINE  

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Posted Thu Nov 8, 2018 10:47 AM

Hi everyone. I replace the mosfet and it work but I can't get it to turn off. The Lynx stay on with plug and try it battery it does the same thing. All the other button work but the off and on do not. I read the part U6   14069u could be the problem but not sure. This my friends system he like a child ask me if it fix yet lol! I need some help thanks! 



#2 -^CrožBow^- OFFLINE  

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Posted Thu Nov 8, 2018 3:26 PM

Are you sure the issue isn't a worn out dome switch on the actual on/off button itself? I just finished modding up another AA user's Lynx II that I discovered would power on itself as soon as I plugged in the AC cord. But I could power it off, but not power it back on. Finally discovered that once I disconnected the ribbon cable from the main board that attaches to the flex circuit for the front panel controls, that it wouldn't turn on when plugged in. So I knew the issue had to be the flex circuit. I was able to clean it up a tiny bit and get it to work most of the time, but advised the client to look into replacing it out. They emailed me yesterday to advised me they had replaced the flex circuit with a new one from Best Electronics and the power on/off and all other buttons were working much better now.

 

So, yeah... see if you can figure out if the dome button on the flex might not be at fault here.



#3 sub2001zero OFFLINE  

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Posted Thu Nov 8, 2018 3:48 PM

ok I will have to look into that but this near mint so I don't see why there will be a problem with them.



#4 Iwantgames:) OFFLINE  

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Posted Thu Nov 8, 2018 5:23 PM

Yea that was my system and the new flex circuit from Best Electronics fixed it up :) and its really easy to fix. But Best does have a minimum order size so youll need to find other items you want on their site as the Flex Circut is only $12 and some change so doesnt meet the minimum on its own

#5 Krip316 OFFLINE  

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Posted Fri Nov 9, 2018 11:51 AM

If it looks similar to this, try cutting about 2mm off the end of the flex circuit.589417ed46575c92f1c81e4fc5e50510.jpg

#6 HunterZero OFFLINE  

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Posted Sun Nov 11, 2018 10:43 PM

If the mylar button matrix can be ruled out (eg, by shorting the appropriate pins on the mylar connector), is there a list of discrete parts on the Lynx 2 motherboard power circuit that commonly go bad, with associated symptoms, and ways to diagnose? Eg, test points? Any Lynx experts compiled information like this?

 

- J


Edited by HunterZero, Sun Nov 11, 2018 10:44 PM.


#7 karri OFFLINE  

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Posted Mon Nov 12, 2018 12:53 AM

I have a faint memory that a long time ago I fixed some power on/off problem by changing the transistor that was in front of the inverters and also the capacitor between the inverters. But without measuring what actually goes on with the power on/off circuitry there is not much you can do.



#8 Stephen Moss OFFLINE  

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Posted Mon Nov 12, 2018 3:16 AM

If you have access to a multi-meter you will have a better chance of finding the fault as you can measure actual verses expected voltages at various points in the circuit.

 

Without that there is not much you can try, if I understand the issue correctly it is that the Lynx turns on as soon as a power source is attached and does not turn of until it is removed. Of the top of my head there are a few of primary things I would look at...

1) A short circuit of flex circuit/stuck power On button

2) A short (or bypassed) Q12

3) A problem with the On/Off power latch comprised of U6, R70, C38 and the Power On/Off buttons 

 

Things you can try without access to a Multimeter...

1) If you press the Off button when a game is running does the game restart as though the reset button had been pressed? If so that my suggest that the lynx is powering off, just powering back on again too quickly for you to see it, possibly due to a stuck/shorted power On button .  

2) Short out C38 (or connect pin 11 of IC 6 to pin 7 of IC 6) with a piece of wire. Does the Lynx turn off with the wire in place or remain on? If it does turn off off does it immediately turn on again when the wire is removed?

     



#9 allthingsanalogue OFFLINE  

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Posted Mon Nov 12, 2018 8:19 AM

If it looks similar to this, try cutting about 2mm off the end of the flex circuit.589417ed46575c92f1c81e4fc5e50510.jpg


I just bought two ribbons from Bradley at Best!

I noticed on my machine that as soo as you remove the ribbon from the connector even once they tend to look like this. I’m undoing the connector properly but they still get scratched off for some reason?

#10 -^CrožBow^- OFFLINE  

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Posted Mon Nov 12, 2018 12:25 PM

The issue that Iwantgames lynx II was doing was that it would power on as soon as you plugged in power to it with a game inserted. You could press the off button and it would turn off and stay turned off. But if I fiddled with the power button it would turn back on again. So it was definitely an issue with the actual dome switch being stuck down somehow but not enough to cause the system to power back on immediately when turning it off. I also confimed it was the button because the Lynx would NOT power on automatically with the front panel ribbon cable detached.



#11 Iwantgames:) OFFLINE  

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Posted Mon Nov 12, 2018 3:18 PM

The issue that Iwantgames lynx II was doing was that it would power on as soon as you plugged in power to it with a game inserted. You could press the off button and it would turn off and stay turned off. But if I fiddled with the power button it would turn back on again. So it was definitely an issue with the actual dome switch being stuck down somehow but not enough to cause the system to power back on immediately when turning it off. I also confimed it was the button because the Lynx would NOT power on automatically with the front panel ribbon cable detached.


Yep and after I got it back the Option 1 button started flaking out and sometimes not registering. Then the Off button stopped working altogether. But with the new parts from Best, it now works perfectly:)




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