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Help! Repairing water damaged PCB from Massage chair.
- Thread starter Jonawald
- Start date
Here's what I have been able to find out so far. Changing the jumpers does not change voltage between GND and UP or DW. The voltage at UP DW reads as shown in image. Just because I know you will ask, I had to replace the 103*8 resistor array beside the IC with a DIY resistor array because the original array had two pins corroded off. Hope it passes inspection. I will post a current CS and PS of the control board here. 
from #264 : "jumpers from Pin 32 to 27/28"
It should be 32 to 28/29 !
I'm re-posting the test procedure:
remember to plug in all the connectors( CN1,CN2 can be left open when testing the control board without the motor).
I added some more test points(see pic below) a total of 10 points.
Please measure them in all 3 combinations (we don't plug in two jumpers in!) of pins 28,29
,a table would be best.
1. We should connect the main and controller boards with CN28.
2. On the main board connect CN1,CN2.
3. On the control board connect CN35 and MgDetect (the opto circuits).
4. In order to activate and set direction of the AC motor.
Use a short wire in the IC socket pins 28,29 to 5v (pin 32)
(one at a time! see pic below)
5. Start by blocking both limit optos(up and down) simultaneously.
No movement should occur with a short in the IC socket at either pin 28 or 29.
6. Now remove the block from both optos.
We should get movement with the shorts(one at a time) in both directions up and down.
At this stage don't get to the limit points yet, just check both directions of movement.
7. If stage 6 is o.k,
Test that the opto limits indeed stop the movement when reached (on both up and down).
"Long " operation in one direction.
Take care, and remove the short jumper immediately ,
if while testing you see it doesn't stop- so no damage will occur.
It should be 32 to 28/29 !
I'm re-posting the test procedure:
remember to plug in all the connectors( CN1,CN2 can be left open when testing the control board without the motor).
I added some more test points(see pic below) a total of 10 points.
Please measure them in all 3 combinations (we don't plug in two jumpers in!) of pins 28,29
,a table would be best.
1. We should connect the main and controller boards with CN28.
2. On the main board connect CN1,CN2.
3. On the control board connect CN35 and MgDetect (the opto circuits).
4. In order to activate and set direction of the AC motor.
Use a short wire in the IC socket pins 28,29 to 5v (pin 32)
(one at a time! see pic below)
5. Start by blocking both limit optos(up and down) simultaneously.
No movement should occur with a short in the IC socket at either pin 28 or 29.
6. Now remove the block from both optos.
We should get movement with the shorts(one at a time) in both directions up and down.
At this stage don't get to the limit points yet, just check both directions of movement.
7. If stage 6 is o.k,
Test that the opto limits indeed stop the movement when reached (on both up and down).
"Long " operation in one direction.
Take care, and remove the short jumper immediately ,
if while testing you see it doesn't stop- so no damage will occur.
yes
It looks like the 74LS00 is o.k.
but the table of #272 and #270 have some mismatches.
Could you please re-check and post table #270 in the following conditions :
1. both Opto devices are not blocked.
In the IC socket connect like this(careful not to short,isolated wires if possible)
2.connect (29 to 32) and ( 28 to 31).
3. remove both wires,then connect (28 to 32) and ( 29 to 31).
The table only has 2 columns (for #2 and #3).
but the table of #272 and #270 have some mismatches.
Could you please re-check and post table #270 in the following conditions :
1. both Opto devices are not blocked.
In the IC socket connect like this(careful not to short,isolated wires if possible)
2.connect (29 to 32) and ( 28 to 31).
3. remove both wires,then connect (28 to 32) and ( 29 to 31).
The table only has 2 columns (for #2 and #3).
That produced some interesting results. Measuring the first portion of this section was boring, but when I swapped the wires to check the second column and turned on power the carriage moved up. I let it go with my finger on the switch. It went clean up to the opto sensor and stopped on it's own accord. Comparing the numbers on the up and down columns. It seems to me, that the control side is doing its thing. So, at least from what I can read from this the problem lies on the other side. The Mains board. I should be able to compare the two circuits and find a problem in there somewhere. Is that right?
Ok. took me a while there. One one hand I have been very busy but also I haven't had much rush with this for right now. I ordered a bunch of components to replace the known bad and under valued ones. Also I am waiting for iRest to get back to me on the IC they said to wait till after Chinese New Year. I still don't have anything but found myself with some time to run this test. The voltages are as indicated in the picture. I also changed the jumpers to move the carriage down and checked the voltages there with the motor unplugged so that conditions would be quite similar. The voltages from the working side were much lower everything in the mv area. I'm guessing right now it is the 8050 transistor that is the problem. I have a bunch on order if that is the case. Let me know if I'm wrong and I'll look for something else.
Jonathan
Jonathan
"The voltages from the working side were much lower everything in the mv area" ?
That is very strange !
Just to be clear:
1.The opto is MOC3020,correct?
2.The working side is the UP.the DW doesn't work ,correct?
3.The readings in post #278 are of the not working DW.
4.The reading of 1.09V (in post #27) is suspicious-too high.
Can you please fill in the the voltages and
resistors values(pink circles) in the following :
That is very strange !
Just to be clear:
1.The opto is MOC3020,correct?
2.The working side is the UP.the DW doesn't work ,correct?
3.The readings in post #278 are of the not working DW.
4.The reading of 1.09V (in post #27) is suspicious-too high.
Can you please fill in the the voltages and
resistors values(pink circles) in the following :
I'm still alive and don't want this thread to die yet. I'll get more time to look at this thing again after this week. Spring break for us. I also have a little challenge i need to work out with getting the IC from iRest. They need a bank transfer for that part and I don't have an account with a bank. I asked if I could pay wiht paypal but that was a no-go.
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