LYNX 2 On/Off Problems Need Help

[sub2001zero]

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!

[+-^CrossBow^-]

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.

[sub2001zero]

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.

[Iwantgames:)]

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

[Krip316]

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

[HunterZero]

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 November 12, 2018 by HunterZero

[+karri]

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.

[+Stephen Moss]

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?

 

[allthingsanalogue]

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

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?

[+-^CrossBow^-]

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.

[Iwantgames:)]

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:)

[sub2001zero]

Hi everyone I still need help i had been busy and just to to look back at it today. I did more test. The buttons do seem to work but when i push the off button I get a black screen still hear music of game but when released come back on. So it does not want to turn off completely. Also when I plug in today and push the on button it came on so I think the cables is fine. so can it be that part 14069u I know that control the power.

[sub2001zero]

i add a picture of the board how do you test u6 too see if that the problem thanks!

[+Stephen Moss]

Hi everyone I still need help i had been busy and just to to look back at it today. I did more test. The buttons do seem to work but when i push the off button I get a black screen still hear music of game but when released come back on.

 

Sounds more like the Backlight button is being operated rather then the Off button. I cannot think/see the screen would go Black and the game keep playing as a result of pressing the off button, but that is exactly what you would expect from pressing the Backlight button. Sounds more like a fault/button-pad alignment issue with the flex circuit to me but the U6 test I mentioned previously will hopefully go some way to confirming that.

 

i add a picture of the board how do you test u6 too see if that the problem thanks!

 

Pin 1 of U6 is the top Left corner (you can see the track linking it to R73), as with all IC's the pin numbering is sequential in an anti-clockwise direction, so pins 8 & 9 are the bottom Left & Right corners respectively & 14 is top Right corner. And as you can see C38 is immediately to the Right of U6/below R70.

 

There are two tests you can do without access to a multi-meter which are a little fiddly and require a reasonable steady hand..

1) As mentioned in my previous post, with the Lynx on Short out C38 (or connect pin 11 of IC 6 to pin 7 of IC 6) with a piece of wire (i.e. a bare metal paper clip). Does the Lynx turn off with the wire in place or remain on? If it does turn off does it immediately turn on again when the wire is removed or remain off?

2) With the flex button circuit disconnected use a piece of wire and connect one (fixed) end to the top end (nearest R70) of C38, then connect the other (free) end to Pin 14 of U6 (turn On) and either Pin 7 of U6 or the other end of C38 (turn Off).

You do not need to hold the wire in place just a brief 1 second touch should be enough to turn the Lynx On/Off and it should remain in its On/Off state until you reconnect connect the free of the wire to applicable turn On/Off points. It may be difficult to see the screen while doing this but you should hear the usual power on click if you have the speaker attached/see the LCD back light go on/off as the Lynx goes on/off.

 

If you do have access to a multi-meter then measure the voltage on all pins of U6 when the Lynx is its on/off states.

[sub2001zero]

so you are saying if i short out c38 it should turn off?

[+Stephen Moss]

Yes, if you short C38 that will put the logic states of the power On/Off latch into the off condition and thus the Lynx should turn off and remain off with the short removed provided the latch and other items relating to the power circuit are operating correctly.

This is only a temporary short to assess if the main power components are working as they should and thus where the problem may lie, not a solution, if you short C38 permanently the Lynx should never turn on.

 

You may find this worth reading, although it refers the the Lynx 1 and thus some of the component references (i.e. Q13) are different from those of the Lynx 2 the circuit itself is the same in both units so you may find it useful.

Edited December 5, 2018 by Stephen Moss

[sub2001zero]

hi where am i contact the wire to see this voltage

I know where u6 is on the board and pin and are on the right side of chip so when i connect with pin 13 to what?

U6 (4069) Pins 13, 12, 11 and 10.

With the Lynx off I would expect to see approximately 5V, 0V, 0V & 5V respectively, once the on button is pressed I would expect those voltages to be reversed

[sub2001zero]

ok i play with today i plug the wall adapter and it turn right on and on 12 and 11 are 8.32 and 8.24 and power light flickers off and on or not at all. Is it the flex board i have no clue i am so confused also I do get a ohm reading on the carbon traces for the off and on

Edited December 6, 2018 by sub2001zero

[+Stephen Moss]

Let go back to basics....

 

Insert a cartridge into the Lynx and connect the power unit and the both the display and button flex circuits and make sure the lynx on not placed on a conducive surface, i.e. wood, rubber, the non printed side of a cerial box.

 

1) When you switch on the power supply the Lynx should be off and with the COM lead of your multi-meter on either pin 7 of U6 or the end of D11 without the black line (furthest from C39/C41) you should measure approximately the following voltages on U6...

 

Pin 1 = 12V

Pin 2 = 0V

Pin 3 = 0V

Pin 4 = 12V

Pin 5 = 12V

Pin 6 = 0V

Pin 7 = 0V (Supply)

Pin 8 = 0V

Pin 9 = 12V

Pin 10 = 12V

Pin 11 = 0V

Pin 12 = 0V

Pin 13 = 12V

Pin 14 = 12V (Supply)

 

You will get 12V instead of 9 because you are not taking current from power from the power unit and thus there are no losses (voltage drop) in the transformer.

If this is correct then proceed to step 2 otherwise what voltages are you measuring on those pins?

NOTE: The pins of U6 are quite close together, try not to sort them out with your meter probe, it can potentially damage and output.

 

2) Use a piece of wire (or anything else conductive) to connect the top end (nearest to R70) of C38 to pin 14 of U6 for a second, the Lynx should switch on and with the COM lead of your multi-meter on either pin 7 of U6 or the end of D11 without the black line (furthest from C39/C41) you should measure approximately the following voltages on U6...

 

Pin 1 = 4 - 6V

Pin 2 = 4 - 6V

Pin 3 = 4 - 6V

Pin 4 = 4 - 6V

Pin 5 = 4 - 6V

Pin 6 = 4 - 6V

Pin 7 = 0V (Supply)

Pin 8 = 4 - 6V

Pin 9 = 4 - 6V

Pin 10 = 0V

Pin 11 = 9V

Pin 12 = 9V

Pin 13 = 0V

Pin 14 = 9V (Supply)

 

You get a reading of 4 - 6 volts on some pins as they form part of a ocsillator running at around 170KHz and your multi-meter cannot react fast enough so it averages out the voltage which are constantly switches between 0 and 9.

If this is correct then proceed to step 3 otherwise what are the voltages on these pins?

NOTE: Keep everything away from T1, it is the 2000 volt transformer for the LCD backlight, if you touch it (or the backlight itself) you can get a nasty nip, if you short it to another part of the Lynx you could fry the entire Lynx.

 

3) Use a piece of wire (or anything else conductive) to connect the top end (nearest to R70) of C38 to the other end of C38 (or pin 7 of U6) for a second, this should turn the Lynx off and the voltages on U6 should revert back to those in step 1 above.

Is this correct? If not what are the voltages on these pins?

 

 

[+-^CrossBow^-]

Curious what became of this. I've got a Lynx sent to me that appears to turn on when it should and turn off with the power button as it should. But it also turns off when you press the backlight button instead of just powering off the backlight. I've tried 2 different flex circuit replacements and both do this. I'm inclined to think that U6 is the problem..but just not sure. I've not checked the voltages from U6 because again it does turn on and off with the right buttons. Just also turns off when you press the backlight and that makes no sense.

 

[bdoi]

Does anyone know  U6 part number and where I can buy it because I have a couple of lynxes with power issue ( which not comes from mosfet or zener diode);)

[+-^CrossBow^-]

Well to update the one I'm working on...

 

The backlight will turn off, provided you give that button a light touch. If you press it hard, then it will actually power off the lynx. Again, I've never seen anything like this and two different flex circuits produce the same results so it has to be something in the logic. But then why does it only turn off if you hard press the backlight button? I did noticed that both of the flexes have a bit of a bow to them when installed as the holes for them to line up with the pegs on the plastic tray...don't seem to quite line up correctly. It might be the left half with the power on/off and backlight button is bowing up too much or something under the shell and as a result, a hard press is causing it to also short the power on/off as well somehow?

 

 

[Nop90]

Check if dirty or something else makes a short circuit near the connector or near the inverter. If there is a short with high impedance, the current flowing in it can be low and can take some time to trigger the inverter off.

 

You can check with a multimeter if there is an high, but not infinite, impedance between the two lines.

 

For testing the lynx did you swapped only the flex or all the top of the lynx. Because the problem could have a mechanical cause: pressing too much the button could push the cable to the  off contact if it's not correctly assembled.

 

[+-^CrossBow^-]

I actually tested it with the cover off initially and it seemed to work correctly. It only does this with the top cover re-installed. The lynx was originally sent to me because if you pressed on the Option 1 or Pause, it would cause the current game to actually reset each time as if you had pressed both buttons. That flex did have issues and the original problem went away once I replaced out the flex. BTW that is how you get them from Best..just the flex so you have to pop the A/B buttons and D-pad off to change that. There are small holes on that plastic tray the flex sits on to line it up and those are a bit off on these replacements it seems. The top has a nasty bow especially but aside from the backlight turning off the lynx if you press it down too hard, it works 100% otherwise now.

 

Noticed that even after replacing the caps, this LCD and sound is still ...ugh... Not that I expected new caps to fix the LCD streaks and bleeding, but I had hoped the sound would be louder and less distorted but I think this Lynx just has a poor speaker on it compared to my own personal ones and others I've serviced.

 

[Jaybezeone]

On 12/7/2018 at 10:34 AM, Stephen Moss said:

Let go back to basics....

 

Insert a cartridge into the Lynx and connect the power unit and the both the display and button flex circuits and make sure the lynx on not placed on a conducive surface, i.e. wood, rubber, the non printed side of a cerial box.

 

1) When you switch on the power supply the Lynx should be off and with the COM lead of your multi-meter on either pin 7 of U6 or the end of D11 without the black line (furthest from C39/C41) you should measure approximately the following voltages on U6...

 

Pin 1 = 12V

Pin 2 = 0V

Pin 3 = 0V

Pin 4 = 12V

Pin 5 = 12V

Pin 6 = 0V

Pin 7 = 0V (Supply)

Pin 8 = 0V

Pin 9 = 12V

Pin 10 = 12V

Pin 11 = 0V

Pin 12 = 0V

Pin 13 = 12V

Pin 14 = 12V (Supply)

 

You will get 12V instead of 9 because you are not taking current from power from the power unit and thus there are no losses (voltage drop) in the transformer.

If this is correct then proceed to step 2 otherwise what voltages are you measuring on those pins?

NOTE: The pins of U6 are quite close together, try not to sort them out with your meter probe, it can potentially damage and output.

 

2) Use a piece of wire (or anything else conductive) to connect the top end (nearest to R70) of C38 to pin 14 of U6 for a second, the Lynx should switch on and with the COM lead of your multi-meter on either pin 7 of U6 or the end of D11 without the black line (furthest from C39/C41) you should measure approximately the following voltages on U6...

 

Pin 1 = 4 - 6V

Pin 2 = 4 - 6V

Pin 3 = 4 - 6V

Pin 4 = 4 - 6V

Pin 5 = 4 - 6V

Pin 6 = 4 - 6V

Pin 7 = 0V (Supply)

Pin 8 = 4 - 6V

Pin 9 = 4 - 6V

Pin 10 = 0V

Pin 11 = 9V

Pin 12 = 9V

Pin 13 = 0V

Pin 14 = 9V (Supply)

 

You get a reading of 4 - 6 volts on some pins as they form part of a ocsillator running at around 170KHz and your multi-meter cannot react fast enough so it averages out the voltage which are constantly switches between 0 and 9.

If this is correct then proceed to step 3 otherwise what are the voltages on these pins?

NOTE: Keep everything away from T1, it is the 2000 volt transformer for the LCD backlight, if you touch it (or the backlight itself) you can get a nasty nip, if you short it to another part of the Lynx you could fry the entire Lynx.

 

3) Use a piece of wire (or anything else conductive) to connect the top end (nearest to R70) of C38 to the other end of C38 (or pin 7 of U6) for a second, this should turn the Lynx off and the voltages on U6 should revert back to those in step 1 above.

Is this correct? If not what are the voltages on these pins?

 

 

Hello,

 

PAssing there and found my case in there

 

My case:

Lynk 2 with no power on.

Screen works;

Flex is new;

 

Step 1 ) all good (12v /0v)

Step 2 ) Fail as nothing turns on the machine. Running same voltage as step 1

I tried to short C38. No changes.

 

Only extra, I shaked a bit and touch 2 places that I wasnt supposed to... and backlight and screen went on.... ?

I wont to that again but it gave me hopes.

 

Any idea to emulate my latch ON position ?