Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Mark,
I am still unable to get a print started... With the carrier removed the Pin (Pad) 5 to GND values are 5.02V and 80mV. in passing the hole, it switches between 5.02 and 126mV, only if perfectly centered (both X & Y) on the led. This implies that the hole is too small. so I re-drilled the 0.026" hole to 0.030" and shimmed the sensor to exactly center the X dimension. I now have 5.02V & 90.2mV. which I expect to be good... Nevertheless, I paralleled a 5600 ohm discreet across the 30k resistor, with a resulting resistance reading of 4.76k.
After pressing X with a good pull-in (no jam indicated) and then executing a  print command, I still get a paper jam, with the carrier stopping with the trigger hole 0.55" to 0.65"  past the CL of the sensor. I can then block the sensor and press continue to have the machine eject the carrier. Recycling power will restore the normal state. Any ideas?
Perhaps I should replace the board... I don't have means to re-program.
Thanks,
Roger

 

Roger,

Sorry about the resistor. The 30K was used in a previous version that used a reflective sensor - It should be about 5K. The higher resistor should work (I think), but it will be more susceptible to noise. If you send it back I will be happy to replace the resistor. If you prefer I can just send you a new resistor and you can replace it yourself.

To see if it is the resistor,  turn the machine on and put a voltmeter from ground to the sensor's collector (the end of the resistor NOT connected to the 5 volt supply). With the carrier  blocking the sensor, it should read 5 volts. When the hole reaches the sensor it should drop to near 0 volts, then go back up after the hole passes through. Do this by manually moving the carrier because it might be hard to see without a scope in real time.

Mark