ninsei Posted January 11, 2019 Share Posted January 11, 2019 Hi. I have a Lynx 2 with the McWill screen mod. worked great until I dropped it now it won't power on. Any help with trouble shooting is appreciated. I get no voltage to VCC/Ground as in step 3 here: https://cdn.shopify.com/s/files/1/1309/0597/files/Quick_Guide_LYNX-II_REV2_0.pdf?2720491075025779069 I guess I'm supposed to see about 5 volts there even if I don't press the "On" button? I don't with either batteries in or power adapter. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 11, 2019 Share Posted January 11, 2019 No you still need to have a cart plugged into it in order to test for Vcc. the Lynx doesn't attempt to turn on without a cart in or unless you short some pins to trick it into thinking there is a cart plugged in. That isn't stated in the instructions, but yeah...still need to plug everything up while still having it open to test this. I ran into that snag myself the first time I did it and was slightly freaking out about it thinking I had hosed up something in the process. Quote Link to comment Share on other sites More sharing options...
ninsei Posted January 11, 2019 Author Share Posted January 11, 2019 Thanks. Yes I have a cart in and have the ribbon cable connected. no power to VCC/ground. Quote Link to comment Share on other sites More sharing options...
+-^CrossBow^- Posted January 11, 2019 Share Posted January 11, 2019 And you have power at the power jack? I don't have a Lynx board in front of me, but you would also need to check if you get anything at the zener diode as well I think. We know it to be a power issue and if you get nothing, then just have to start at the AC jack and start working component to component. Quote Link to comment Share on other sites More sharing options...
ninsei Posted January 11, 2019 Author Share Posted January 11, 2019 Ah: if I put 5v directly to capacitor C41 it powers on nicely. I assume that means the mosfet is faulty. I just ordered a new mosfet. 1 Quote Link to comment Share on other sites More sharing options...
+Stephen Moss Posted January 14, 2019 Share Posted January 14, 2019 (edited) I guess I'm supposed to see about 5 volts there even if I don't press the "On" button? I don't with either batteries in or power adapter. No, as the Lynx is off there is no current flow and thus not voltage drop so I would expect you to see the raw in comming voltage (around 12V with power unit and 9V with batteries). Ah: if I put 5v directly to capacitor C41 it powers on nicely. I assume that means the mosfet is faulty. I just ordered a new mosfet. The MOSFET maybe faulty, however a drop is highly unlikely to damage the MOSFET, but it may crack a solder joint. I would suggest applying power and measuring the voltage across the supply pins of U6 (pins 7 & 14), if you cannot measure the supply voltage there then one of your power rails is open circuit and you will have to trace it back from there to the battery connectors/power socket. Edited January 14, 2019 by Stephen Moss Quote Link to comment Share on other sites More sharing options...
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