Since I've got to fix a bunch of power adaptors, I will try to make life a bit easier for myself. Instead of storing a few laptops just for testing purposes, I will try to make a universal tester instead.
It will have different DC input sockets from different laptops, for some of the main laptops.
Some are 2 pin so they just need voltage reading and dummy load.
Some are 3 pin, for example HP, Dell and Lenovo. HP will need voltage reading from middle pin, Lenovo will need resistance reading from middle pin and Dell will need a onewire reading from middle pin (got this part done already).
First it will need to see if it even has a reading from the middle pin. If it does, it will show adaptor data on LCD based on that reading.
I can compare it to the data written on the adaptor. If all is OK, I will connect dummy load.
Dummy load would probably consist of 30x 120R 5W resistors, grouped as 12+2+6+6+2+1+1 or something similar, all in parallel and every group has its own switch or relay. This seems like a cheap way to get a load which I can switch as needed, from around 40W to 90W supplies. Or is there any better method? Lightbulbs, heating elements?
When applying the load, voltage should stay between certain range. How much should the maximum error be?
Maybe voltage ripple reading would be useful. What could be an okay ripple voltage on these things?
Any other ideas about this before I start doing anything?
Data about HP middle pin voltages based on wattage? I have my data but would like to see some semi-official data to back it up
It will have different DC input sockets from different laptops, for some of the main laptops.
Some are 2 pin so they just need voltage reading and dummy load.
Some are 3 pin, for example HP, Dell and Lenovo. HP will need voltage reading from middle pin, Lenovo will need resistance reading from middle pin and Dell will need a onewire reading from middle pin (got this part done already).
First it will need to see if it even has a reading from the middle pin. If it does, it will show adaptor data on LCD based on that reading.
I can compare it to the data written on the adaptor. If all is OK, I will connect dummy load.
Dummy load would probably consist of 30x 120R 5W resistors, grouped as 12+2+6+6+2+1+1 or something similar, all in parallel and every group has its own switch or relay. This seems like a cheap way to get a load which I can switch as needed, from around 40W to 90W supplies. Or is there any better method? Lightbulbs, heating elements?
When applying the load, voltage should stay between certain range. How much should the maximum error be?
Maybe voltage ripple reading would be useful. What could be an okay ripple voltage on these things?
Any other ideas about this before I start doing anything?
Data about HP middle pin voltages based on wattage? I have my data but would like to see some semi-official data to back it up
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