Deleted
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Post by Deleted on Oct 22, 2013 22:42:36 GMT -5
Remove the cap from the circuit and test it. Should read around 10 ohms.
Test the impedance (ohms) between the metal heat sink, and metal transistor, with the transistor unplugged from the circuit board. Should be very high.
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Post by John Shelley on Oct 22, 2013 22:50:47 GMT -5
the transistor is held on to the heat sink with 2 bolts, they are insinuated by thin Bakelite tubes and washers, should those have cracked there could be leakage between the transistor and the heat sink, which is grounded, effectively partially shorting it out, the best fix in that case is use nylon bolts.
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Post by Adam D. on Oct 23, 2013 1:42:13 GMT -5
Remove the cap from the circuit and test it. Should read around 10 ohms. Test the impedance (ohms) between the metal heat sink, and metal transistor, with the transistor unplugged from the circuit board. Should be very high. I did that and there isn't continuity, as John said there shouldn't.. I tested the cap using resistance and there isn't continuity.. Though it tests fine with capacitance.. If that tells anyone anything..
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Deleted
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Post by Deleted on Oct 23, 2013 9:56:58 GMT -5
It tests in spec? 10uf?
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Post by Adam D. on Oct 23, 2013 14:08:45 GMT -5
It's one of the first things I did.. It tests around 10.5uf, slightly high, but within tolerance..
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Deleted
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Post by Deleted on Oct 23, 2013 20:42:01 GMT -5
Should be fine.
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Post by Adam D. on Oct 23, 2013 20:55:37 GMT -5
I'm going to my friends house tomorrow, he's got a bunch of those same type of transistors lying around.. I'm going to try that too and see if there is any difference..
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Post by Adam D. on Oct 26, 2013 21:42:17 GMT -5
I brought it back to my friends house complete, and we did some tests on it with equipment I don't have.. The fan's wattage while running and pot at maximum (5K) resistance reads .18 watts while running, the MOV chip is good, the transistor is good, the resistors are all good, and the capacitor is fine as we determined.. Even my theory about a motor winding being dead is most likely not the case either.. Soo either Casablanca had somebody make these pot switches custom out of material that's able to dissipate heat and not burn up.. or something else.. Either way, chances are this thing will have to be modified, for it to work correctly.. He also did some tests bypassing the transistor, and some other things and he seems to think the transistor is fine.. I personally would just change out the transistor and see if there is any difference. I even thought that maybe transistor is not working correctly or giving issues.. he says transistors either work or not.. So any thoughts anyone?
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Deleted
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Post by Deleted on Oct 26, 2013 21:48:59 GMT -5
0.18 watts is not accurate for the motor current draw. Maybe you meant something else?
Casa's pots are standard 1/2 watt pots.
What your friend says about transistors makes sense, I've never heard of one failing partially.
It's just a crappy design. There's a reason why more than half of them failed, and why Casablanca stopped offering replacement parts and started selling 3 speed conversion kits instead.
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Post by Adam D. on Oct 26, 2013 21:57:44 GMT -5
We tested the current going though the pot while in operation and that's what we got.. It's less than a watt running through the pot.. 5k 5watt pot and it's getting hot.. There's gonna be a way to get it to work correctly, but most likely it's gonna have to be modified.. either with an extra resistor, or pot..
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Deleted
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Post by Deleted on Oct 26, 2013 22:33:12 GMT -5
I thought you meant the motor current draw.
If you figure out a way to modify it let me know.
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Post by Adam D. on Oct 26, 2013 22:53:17 GMT -5
Ok.. Will do, I'll keep this updated..
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Jared H.
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Trying to get bi
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Post by Jared H. on Oct 27, 2013 17:04:02 GMT -5
good luck to you. you'll need it. :/
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Post by Adam D. on Oct 31, 2013 15:04:29 GMT -5
Update:
Replaced the 39 ohm resistor with a 100 ohm, and the pot stays mildly warm.. Same pot with the original 39 ohm resistor was getting hot.. Now that there is a 100 ohm resistor in place, I will need a 15k pot or higher seeing how fan slows down to more of a mediumish slow speed, like a normal 3 speed fan.. So far it looks good as far as a fix..
I've measured it down to a 15k pot for a good slow speed
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Post by Adam D. on Nov 3, 2013 14:36:37 GMT -5
Lets keep this subject over here.. You mean it wasn't getting warm as in staying cold? If the pot you were using was staying cold and still burning out, that would be a bit difficult to believe.. What ever the case may be.. I'll run this one on and off for several months and see how it holds up.. I don't know if this will be a fix for every fan, but time will tell with this particular fan and I'm going to look into the Victorian I have and see what the problem is with it whether if it's the same issue or something else..
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