Originally Posted by
john-100
photos of all the EzRouter electronic hardware would be usefull (showing the BOB , power supplies and stepper drivers )
any voltage on the 25pin printer port connector should be between 0V and +5V
to test Pins 1,14,16,17 and measure 64.3 DCV could indicate a regulator powering the output side of the breakout board has failed
it is not a good sign and you may have a damaged printer port
a photo of the "red" BOB will help to decide if the regulator is on the BOB or its a separate power supply thats failed
assuming the stepperdrivers have opto-isolated inputs then
I would expect the BOB will have 5 optoisolators connected to the printerport inputs
may use a 74LS14 to buffer the BOB inputs
the 12 printerport outputs are very often buffered by two 74HCT245 octal buffers
all the IC's will be powered by a 5V supply with the negative terminal connected to the printerport ground
John