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

Mark,
I used the following guidance from your tutorial:
" Slide the carrier through the slot of the NPIS with the leading edge at the interface of the input rollers. Holding the Carrier against the Carrier Guide, mark the carrier 2.5 inches from the center of the NPIS. Now drill a small hole 4mm from the edge of the Carrier. I used a .026 inch drill, but anything in that range or a bit larger should work just as well. See [Photos]."
This puts the hole 0.90" before the CL of the NPIS after the initial X pull-in. At that point, the green ready light is on with no jam light, so this seems to be OK, and ready for a print command from the PC. am I correct?
Roger

 

Roger,

One other thing that could cause this is the position of the hole when you start the print. The timing is rather loose, but the hole cannot be too far from the sensor when you start, probably 1.5 inches would be the max. Haven't measured it.

Mark



At 07:41 AM 4/8/2015, you wrote:

Roger,

About the only other thing I can think of is some sort of slippage, where the carrier doesn't advance quickly enough and it "times out". One thing we could try, if you want. Send me your board and I'll try it in one of my machines. I think you have my address.

Mark

At 06:12 PM 4/6/2015, you wrote:

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


On 4/6/2015 5:31 AM, Mark Lerman mlerman@... [Homebrew_PCBs] wrote:

 

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

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