Hello. I'm looking for help diagnosing a Lenovo Flex 3-1480 (80R3000TCF).
I replaced the display/touchscreen assembly last week. I was not able to power it on prior to the display replacement, but I didn't have the AC adapter, and assumed it was simply dead. Since replacing the display, the owner of the laptop has brought me the adapter, but the device is still completely non-responsive.
In my experience, laptops with user-removable batteries will power on just fine with the battery removed (and the AC adapter connected, of course). This laptop does not have a user-removable battery, and I'm not sure if it should power on without it when functioning normally or not. The one I have here doesn't, but I don't know if that by itself indicates a problem.
At this point, I'd be satisfied to know simply whether the problem lies with the battery or the board - however, if it is a board issue, I'd much prefer to repair rather than replace it, if possible.
I'd greatly appreciate any help - diagnoses, tips, more things to try. Anything at all.
Symptoms:
-No activity from LEDs/fan/display, with or without the AC adapter plugged in
-Pressing the power button produces no response
Things I've tried:
-Pressing the power button with the AC adapter connected and battery disconnected - no response
-Disconnecting the battery and AC adapter, removing the coin cell, then pressing and holding the power button for upwards of 60 seconds - no change
-Removing RAM/HDD/Wifi module, individually and in various combinations - no change
-Replacing RAM with a known working module - no change
-Charging/discharging the battery cells (with an external charger) - no change
Observations:
-Visual inspection of the board revealed nothing
-AC adapter measured at 19V
-19V measured at the AC adapter connector on the board
-When the battery is disconnected, or the AC adapter is not plugged in, I read 0.3V to 0.4V at the positive and negative pins of the battery connector
-When both the battery and AC adapter are connected, I read 220mV at the positive and negative pins of the battery connector - regardless of the state of charge of the battery
-Direct measurement of the battery cells seems normal - 3.7V
-When power is supplied to the board (from either the battery or the AC adapter), I read no voltage across the terminals of the power button, pressed or unpressed
-With no power to the board, measured ~9kOhm across the power button unpressed, no resistance when pressed
-Was able to find 3.3V and 12V on the board, but not 5V (by measuring voltages more or less randomly - I don't really know what to look for here) with the AC adapter connected
-Coin cell voltage is 3.0V
-I have been able to find two fuses - both seem okay (<1Ohm)
-Attempting to measure the frequency of any clock using my multimeter yields nothing - admittedly, I may be doing it wrong.
Motherboard PN: 5B20K37656
Battery: L14M3P21
I have a reasonable DMM, but no access to an oscilloscope/logic analyzer/function generator (for the moment, at least).
Thanks.
-Roger
I replaced the display/touchscreen assembly last week. I was not able to power it on prior to the display replacement, but I didn't have the AC adapter, and assumed it was simply dead. Since replacing the display, the owner of the laptop has brought me the adapter, but the device is still completely non-responsive.
In my experience, laptops with user-removable batteries will power on just fine with the battery removed (and the AC adapter connected, of course). This laptop does not have a user-removable battery, and I'm not sure if it should power on without it when functioning normally or not. The one I have here doesn't, but I don't know if that by itself indicates a problem.
At this point, I'd be satisfied to know simply whether the problem lies with the battery or the board - however, if it is a board issue, I'd much prefer to repair rather than replace it, if possible.
I'd greatly appreciate any help - diagnoses, tips, more things to try. Anything at all.
Symptoms:
-No activity from LEDs/fan/display, with or without the AC adapter plugged in
-Pressing the power button produces no response
Things I've tried:
-Pressing the power button with the AC adapter connected and battery disconnected - no response
-Disconnecting the battery and AC adapter, removing the coin cell, then pressing and holding the power button for upwards of 60 seconds - no change
-Removing RAM/HDD/Wifi module, individually and in various combinations - no change
-Replacing RAM with a known working module - no change
-Charging/discharging the battery cells (with an external charger) - no change
Observations:
-Visual inspection of the board revealed nothing
-AC adapter measured at 19V
-19V measured at the AC adapter connector on the board
-When the battery is disconnected, or the AC adapter is not plugged in, I read 0.3V to 0.4V at the positive and negative pins of the battery connector
-When both the battery and AC adapter are connected, I read 220mV at the positive and negative pins of the battery connector - regardless of the state of charge of the battery
-Direct measurement of the battery cells seems normal - 3.7V
-When power is supplied to the board (from either the battery or the AC adapter), I read no voltage across the terminals of the power button, pressed or unpressed
-With no power to the board, measured ~9kOhm across the power button unpressed, no resistance when pressed
-Was able to find 3.3V and 12V on the board, but not 5V (by measuring voltages more or less randomly - I don't really know what to look for here) with the AC adapter connected
-Coin cell voltage is 3.0V
-I have been able to find two fuses - both seem okay (<1Ohm)
-Attempting to measure the frequency of any clock using my multimeter yields nothing - admittedly, I may be doing it wrong.
Motherboard PN: 5B20K37656
Battery: L14M3P21
I have a reasonable DMM, but no access to an oscilloscope/logic analyzer/function generator (for the moment, at least).
Thanks.
-Roger