Faulting batch of sensors?
Only after that post your thoughts feelings of my $750 paper weight. Not melting any PLA so as not to void warranty!
RE: Faulting batch of sensors?
do you have a multimeter? i would unscrew the sensor from the extruder body and test it. measure the dc voltage on each pin to the power supply ground. they are labeled on the board. the outer pins should be 0 and 5 v and the middle pin should be 5 with nothing between the jaws of the sensor. the put something opaque between the jaws and the middle pin should go to 0 V
RE: Faulting batch of sensors?
I have 5 vdc to ground at the sensor, nothing at signal when field is interupted.
RE: Faulting batch of sensors?
IR sensor can be verified very easily. Unscrew it from the head. Measure the voltage between Ground and Sensor pin. Watch the voltage change while you're placing something between the IR gate.
Check also between 5V and Ground pins that you have +5V, not -5V and not 0V
I can also see there is no cap on the IR sensor but there should be a plastic cap. Is the screw shorting something?
Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram
RE: Faulting batch of sensors?
Positive 5 vdc to ground and never checked signal . Sensor state as you can see is a 1 with power and 0 (zero) when deenergized (by unplugging connector). Placing a black object in gap did not change the state of the sensor so my conclusion is the firmware looks for 2 signals of different values, one to verify gap is clear during self test and another value when gap is blocked. I looked at the code in Arduino IDE (took some work in the platform.txt and preferences) but it is fairly simple for what it is intended to do. It is more of a perk then a safety feature but if Prusa designed it as is I would like the feature to work, especially with replacement sensor.
I am printing with no other bugs and continue to work with the developers on a fix/solution.
RE: Faulting batch of sensors?
The typical IR sensor is OC so there won't be anything at the output unless a pull-up is added.
RE: Faulting batch of sensors?
Getting old sucks ... why do I see TWO rows of pins in this image? Shouldn't the connector be plugged into ONE of them?
RE: Faulting batch of sensors?
top row - base printer
bottom row MMU2 interface cable
RE: Faulting batch of sensors?
top row - base printer
bottom row MMU2 interface cable
This is too funny - it is so obvious what the problem is and no one is seeing it. That is NOT a three row connector, there are only two rows, and we can see them both. That means the plug is NOT plugging on to anything. It's just jammed in and wedged. Of course it won't pass diags.
Place the cable on the row of pins and it might just work as expected.
ps: I'll give it a small chance the plastic of the connector housing is really shiny and that second row of pins is just a reflection ...
RE: Faulting batch of sensors?
The typical IR sensor is OC so there won't be anything at the output unless a pull-up is added.
So if there is 5 vdc at the sensor why is the Wizard/selftest erroring?
RE: Faulting batch of sensors?
John, I can't say why things are erroring out. Not there to do a hands on. So much of my input is theory. But is it likely there is a batch of sensors out there that are defective from the factory? Sure, there are many places a build can go bad; but Prusa claims they test every part, and they show a video that implies they really do (it may even have been the opto being tested).
There are pullups on the board, so a person should see the output pin toggle low-hi as something is inserted (should be a metal something to ensure it is opaque to IR). I've not verified the open state - could be hi or could be low. But typical OC operation would be low until gap is blocked.
Did you happen to verify the EINSY side cable plug is indeed ON the pins, not beside the pins?
RE: Faulting batch of sensors?
Getting old sucks ... why do I see TWO rows of pins in this image? Shouldn't the connector be plugged into ONE of them?
RE: Faulting batch of sensors?
The typical IR sensor is OC so there won't be anything at the output unless a pull-up is added.
RE: Faulting batch of sensors?
Getting old sucks ... why do I see TWO rows of pins in this image? Shouldn't the connector be plugged into ONE of them?
RE: Faulting batch of sensors?
Three parts at play here: any of which can cause the symptoms. So looking at it systematically to eliminate them one at a time... Not trying to talk down to you, I'm just attempting to be thorough.
If you have measured values at the IR board itself, and see +5v across the GND/5V pins, what is the voltage at the OUT pin? If I read the thread right, seems you have not measured it, and have relied on the LCD value. So it'd be worth popping the sensor cover, and measuring OUT. Also, important to remove the sensor to access the gap (don't trust the flag to work, there are known issues with the flag). Tape the thing down so it doesn't become a four hand operation, and while measuring the OUT pin, insert a screwdriver tip or piece of aluminum foil into the gap (many plastics are translucent to IR). If that has zero effect, e.g., pin stays at 5v, it could be a bad sensor or a short in the cable. If you measure a toggle, then check the LCD for a similar transition.
You can pop the center wire out of the connector jacket by carefully depressing the metal tab/clip mid connector and pulling the wire out of the housing. Then repeat the test sensor test. If the OUT pin is still stuck, then you have high confidence the sensor is not working.
If the sensor now toggles, move on to the cable or EINSY. Pull the cable loose from both ends, ohm for continuity between wires at one end of the cable: GND to +5, GND to OUT, OUT to +5. If those pass (all open), then check continuity down the cable: GND to GND, OUT to OUT, +5 to +5 (all 0 ohms).
If all the cable continuity conditions above pass, then the EINSY is suspect.
A thorough and methodical list of things you've verified might help Prusa not waste your time on the next phone call.
ps: I have not deduced the circuitry on the sensor board, but I have found a few AliExpress replacements that look similar:
