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So, measuring the resistance between pins 1 & 2 give me 820 ohms so does that mean the resistor is fine?if you have a multimeter, measure in ohms by touching solder pads 1 and 2 and hopefully you'll measure 820 ohms. If not, measure 1 to 3 (I cannot be sure where which pad (2 or 3) the copper trace connects below the proximity sensor).
if you get infinite resistance both ways, either the resistor or the solderjoints on the resistor are bad.
also, double check that the solder under pad 1 in my photo is a good solder joint.
View attachment 127746
Yes, the resistor is ok unless something strange is happening with heat causing it to disconnect when it gets warm (unlikely so let's move on).So, measuring the resistance between pins 1 & 2 give me 820 ohms so does that mean it's fine?
Anything else to check?
From this diagram or the previous one?
Hi Les,If this happens the board is working.
Hi Les,After seeing the suggestion that you use a digital camera to check the emitter I just scanned through the following posts when I saw the pictures showing the infra red emitter working. I did not read the text so assumed it was the suspect sensor board. Before replacing the 820 ohm resistor I suggest checking the voltage on the bottom pin of the board and between the two bottom pins on the sensor chip.
I hope you didn't hold the battery across pins one and two. It should be from the 9v (positive) to pin 2 (negative battery terminal). Then measure with your volt meter the voltage across pin one and pin 2 while the battery is connected. You can damage the IR led if you connect it directly.Hi there,
Sorry for the delay but I had to pop to the shops for a battery to to test this and only back now.
From pins 1 to 2 the 9v (9.6v to be precise...) carries across fine. If I go from pins 1 to 4 then the output at pin 4 is roughly 3v by time it passes the sensor.
Anything else to try with this approach?
Hi there,Then you can plug in the unit,
I hope you didn't hold the battery across pins one and two. It should be from the 9v (positive) to pin 2 (negative battery terminal). Then measure with your volt meter the voltage across pin one and pin 2 while the battery is connected. You can damage the IR led if you connect it directly.
I could get someone to give me a hand tomorrow if you were able to instruct me?Finally, if you can get someone to help you, we can check the detector side - you'll definitely need one or two extra pairs of hands to do that.
I'm not sure I did the checks correctly after reading this againif you have a 9v battery, connect positive to my red 1, and negative (black wire) to the cathode (across the part form red 2. Then measure voltage from red 2 to the cathode and report back. Hopefully it is between 0.8 and 1.8v.
Cathode is minus, or the direction the arrow points to. If youbcan think of current flows from (+) to (-) in the direction of the arrow.I'm not sure which is the cathode pin?
This would indicate an open circuit.red to pin 1 and multimeter black to pin 2. For this I was getting 9.6v.
Hi there,If you have a multimeter with a "diode test" which will basically read a voltage drop and beep when it's low..
- of multimeter on pin 3
+ of multimeter on pin 4
It should indicate OL or something out of range.