Hi All - I recently bought a Harman Karon ST-8. It worked for a little while, long enough for me to start to really like it, and then the motor - a Papst GS 38.09 - conked out. I asked a tech look at it, and he diagnosed it with a bad hall effect sensor, a photo of which is attached.
Apparently, dual output hall effect sensors with leads (as opposed to SMT) can not be found. Also, replacement motors also can't be found - I have an eBay search saved just in case one pops up, but so far, nothin'.
So, I'm wondering if anyone has any ideas on how to make the current motor go, or barring that, any ideas on how to replace the motor all together? I don't mind it being a little kludgey.
Thanks!
Apparently, dual output hall effect sensors with leads (as opposed to SMT) can not be found. Also, replacement motors also can't be found - I have an eBay search saved just in case one pops up, but so far, nothin'.
So, I'm wondering if anyone has any ideas on how to make the current motor go, or barring that, any ideas on how to replace the motor all together? I don't mind it being a little kludgey.
Thanks!
Attachments
The Source Turntable: Papst GS 38-09 Data Sheet with Motor Board Circuit Diagram
Modern versions of hall effect dual output sensors are available-
Dual Hall Sensor IC with Speed and Direction Detection (MLX92251) #Melexis
a3423.indd - 77708.pdf
Modern versions of hall effect dual output sensors are available-
Dual Hall Sensor IC with Speed and Direction Detection (MLX92251) #Melexis
a3423.indd - 77708.pdf
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Thanks for the suggestions. Unfortunately, the ones you referred to don't have the right pins in the right positions to put in place of the existing sensor. I need something with a pin out something like...
Vcc Out2
Out1 Gnd
And the outputs both need to switch with polarity.
Vcc Out2
Out1 Gnd
And the outputs both need to switch with polarity.
Keep an eye out for either Dual 701 or 721 motors, they're VERY similar, and use the same SBV556 hall effect sensors. Another source might be motors from the Revox 790 range.
All these motors are Papst or Papst derived.
All these motors are Papst or Papst derived.
Thanks for those pointers. There is actually a Revox b790 motor for sale on eBay in the US right now. It is a Papst motor, but definitely not identical to the one from my machine - see attached image.
Do you think I might be able to swipe the hall effect sensor from this motor?
Update: I found a couple photos of the EDS1000 - which I think is the motor from the Dual models you mentioned. I attached those as well.
Do you think I might be able to swipe the hall effect sensor from this motor?
Update: I found a couple photos of the EDS1000 - which I think is the motor from the Dual models you mentioned. I attached those as well.
Attachments
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I have a Dual 721 motor and it uses the same hall effect sensors, as does the Dual 701.
Both of these should be a more easily available than the motor fitted to the HK.
Good Luck
Both of these should be a more easily available than the motor fitted to the HK.
Good Luck
Thanks - I'll keep my eyes peeled. Unfortunately the Revox motor on eBay was sold about an hour ago.
I'm not sure how he diagnosed the bad sensor - I would guess he used a scope and saw it wasn't outputting a signal when a magnet went by, but that is honestly a complete guess.
I also agree that it would be a shame to destroy a motor just for a part, but it might be the only option available. I did find a couple of part suppliers that indicate on their web sites that they have the SBV556 part that ralphcooke mentioned, and I found other posts here and there suggesting it as the right replacement. I have asked for a quote - I'll report back if I hear from them.
I also agree that it would be a shame to destroy a motor just for a part, but it might be the only option available. I did find a couple of part suppliers that indicate on their web sites that they have the SBV556 part that ralphcooke mentioned, and I found other posts here and there suggesting it as the right replacement. I have asked for a quote - I'll report back if I hear from them.
Please ask him for future reference.
This motor was used in many different turntables.
Sensor access is not possible if the motor is still closed and running.
This motor was used in many different turntables.
Sensor access is not possible if the motor is still closed and running.
Sensors are available at Mouser...see if suitable.
But it is simply a semiconductor device, so the circuit must be checked.
Very common in car ignition systems, ABS systems in cars, and seat belt systems.
But it is simply a semiconductor device, so the circuit must be checked.
Very common in car ignition systems, ABS systems in cars, and seat belt systems.
Oh I've looked at the ones on mouser - none supply the needed signals on the needed pins to fit in the space allotted.
My memory is unfortunately shot but as I own the above mentioned turntable and both Oracle Delphi and Alexandria I can guarantee the following.
I have repaired at least 2 of these papst motors where disassembly was required and fault was coil wire open between the solder point and the wound part.
I have also repaired others that did not require disassembly but cannot remember the details.
I have not come across a faulty hall sensor so would recommend looking for a damaged motor with hopefully good hall sensor to try and build up a working motor.
Good luck,
sp.
I have repaired at least 2 of these papst motors where disassembly was required and fault was coil wire open between the solder point and the wound part.
I have also repaired others that did not require disassembly but cannot remember the details.
I have not come across a faulty hall sensor so would recommend looking for a damaged motor with hopefully good hall sensor to try and build up a working motor.
Good luck,
sp.
Thanks for that pointer. I think I found there that has the correct signals, however, my tech says that a SIP package will physically not work. I think it needs to be something like a SOT-24 package, with the two outputs at the corners, and Vcc and ground at the other two corners.
From Unisonic, I learned that what I think what I need is a hall sensor that has "complementary outputs" - that at least gives me another term to use in google.
From Unisonic, I learned that what I think what I need is a hall sensor that has "complementary outputs" - that at least gives me another term to use in google.
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Can you post a photo of the faulty sensor?
With a measuring ruler / tape alongside, so that some idea can be had of its size...
With a measuring ruler / tape alongside, so that some idea can be had of its size...