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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.
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).
if 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.
if 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.
befor replacing any components on the board I suggest doing the following . From the picture in post #18 this is my understanding of the connections to the board. Counting from the bottom. I think the fists connection is the positive supply to the IR emitter. The next one up is the positive supply to the sensor. the third connection is ground and the top connection is the sensor output signal. Can you get a positive voltage with respect to ground on the bottom two connections . (An post the value of these voltages.) Connect you meter between ground and the top connection. With nothing reflective in front of the sensor the voltage reading should be a bit less than the reading you measured on the next to bottom connection. Now if you place something reflective (White paper or reflective metal.) a few mm from the sensor the reading should drop to close to zero. If this happens the board is working. You could then do this test with the sensor in it's original position and note the readings when the white part of the encoder disk is in front of the sensor and when the black part of the encoder disk is in front of the sensor. post the voltage readings. The function of the sensor is to detect the wite and black positions of the disk.
I think at this stage I'm pretty certain that this sensor board is faulty but just not certain which component on the board is to blame.
The reason I'm pretty certain is the the wee sensor isn't emitting an IR light. The cradle has three such sensors and this one is the only one not showing any IR light.
It might be a very valid test in other circumstances, perhaps worth knowing anyway that the pins are as you have described.
I need to go get a 9V battery and carry out that other test that was described just before yours.
Thanks a million though, I'll get to bottom of this yet will all this great advice!!
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.
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.
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.
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.
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 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.
What could make it die, is if the battery is 9V, it's possible to connect a 9V battery briefly backwards.
A diode with a low voltage drop in the main power or even one in series with the emitter portion of the sensor.
You could remove the 820 ohm resistor and use wires to an 820 ohm resistor in series with a diode. We can also resize that resistor to compensate for the voltage drop.
(9-0.6)/10e-3 = 840; 10 mA
So R=(9-2*0.6)/10E-3 <= 780 ohms (normal diode e.g. 1n4001)
Whatever us the closest 5% value; 1/4 W should work
The band on the diode should face the same way as the schematic symbol. Toward (-).
if 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.
I'm not sure I did the checks correctly after reading this again
I had the battery+ connected to the 9v on your diagram, the battery - to pin 2. I then had the multimeter red to pin 1 and multimeter black to pin 2. For this I was getting 9.6v.
I'm not sure what you suggested for the second part, red 2 to the cathode? I'm not sure which is the cathode pin?
Cathode is minus, or the direction the arrow points to. If youbcan think of current flows from (+) to (-) in the direction of the arrow.
It is the band side of the diode.
If you have a multimeter with a "diode test" which will basically read a voltage drop and beep when it's low..
no power
- of multimeter on pin 3
+ of multimeter on pin 4
It should indicate OL or something out of range.
then shine a bright light like an incadesent flashlight the voltage drop indicated would get lower.
If you have a multimeter with a "diode test" which will basically read a voltage drop and beep when it's low..
no power
- of multimeter on pin 3
+ of multimeter on pin 4
It should indicate OL or something out of range.
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