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  1. #21
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    the circuit wouldn't work the way you drew it, here is something that would if I understood your intention correctly - I don't recognize the element in the green circle, that is a capacitor symbol, and it doesn't make sense there

    dscf1068.jpg

    my idea being that the AC coming to the rectifier goes through the switches, if they are all closed, then the rectifier will have DC- on the F- and DC+ on the 47, probably around 24V or so, that will power the element between the F+ and F-, if that is indeed a solenoid coil, will have resistance of 50 to 100 ohms probably, the value of the fuse might provide a clue, if you can't measure anything on the F+ and F- leads going to the mystery component in the unreachable space, then that might be the reason why this circuit was disabled

    if there is 28V AC coming to the rectifier (on the "1" and the other red wire, where there is a clipped stub left), you should be able to measure DC on the F- and 47 to check if it actually works

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  3. #22
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    I'm guessing a little bit, but it seems to me that if there's no DC voltage between F- and 47 the rectifier isn't working properly.

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    I wonder if it powers a motor to drive the carrage?

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    Quote Originally Posted by jz79 View Post
    the circuit wouldn't work the way you drew it, here is something that would if I understood your intention correctly - I don't recognize the element in the green circle, that is a capacitor symbol, and it doesn't make sense there

    dscf1068.jpg

    my idea being that the AC coming to the rectifier goes through the switches, if they are all closed, then the rectifier will have DC- on the F- and DC+ on the 47, probably around 24V or so, that will power the element between the F+ and F-, if that is indeed a solenoid coil, will have resistance of 50 to 100 ohms probably, the value of the fuse might provide a clue, if you can't measure anything on the F+ and F- leads going to the mystery component in the unreachable space, then that might be the reason why this circuit was disabled

    if there is 28V AC coming to the rectifier (on the "1" and the other red wire, where there is a clipped stub left), you should be able to measure DC on the F- and 47 to check if it actually works
    Voltage between 47 and F--- is .506vdc at rectifier. Same voltage at F+ and F-- as close to mystery device as I can get.

    Green circle: Normally open contacts in a relay.. 28vac terminal is actually 30.32. output. Fuse is 10amp.

    FWIW, 12.74vdc between 1 and 47 at rectifier.

    The circuit as drawn is what is on the machine. Took nearly a whole day to trace down each wire.

    What is your take on what the circuit should be?

    BT.

    This circuit has nothing to do with the rapid carriage motor.

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    inputs to the rectifier are "1" and "28V" in your drawing (the red wires in the picture, and note one of the red wires went somewhere and was cut), measure the AC between those, not against common ground, if there is 28~30V AC between those 2 pins, then there should be DC on the "F-" (negative) and "47" (positive), if the DC isn't there - the rectifier isn't working

    I suspect there is also a mistake in your drawing around the pin "1" (or the drawing isn't 100% complete), it is a loop and there can't be any input to rectifier, that is why I put the red cross that might indicate where the error might be and the blue represents the AC coming into the rectifier through those switches/relays

    that being said - that normally open relay (that I couldn't understand in the green circle) - look at what is activating that, if it doesn't close, the circuit again makes little sense

    if the fuse on the DC side is 10amp, and we assume 2-3amps current going there under normal circumstances, then the solenoid (we assume it is a solenoid there) coil should measure around 10ohms, more if the current under normal conditions is lower, but there should be resistance there, if it is completely open or resistance is over lets say 200 ohms, then I doubt it can do much work, at 2 amps that circuit will consume 50W, which seems more or less reasonable

    and if the resistance is lower than 2-3ohm (which may read as a short on a multimeter), then there might also be something wrong with that device there, since it would indicate that it would pass current close to the fuse max rating which usually isn't by design

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  8. #26
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    Quote Originally Posted by jz79 View Post
    inputs to the rectifier are "1" and "28V" in your drawing (the red wires in the picture, and note one of the red wires went somewhere and was cut), measure the AC between those, not against common ground, if there is 28~30V AC between those 2 pins, then there should be DC on the "F-" (negative) and "47" (positive), if the DC isn't there - the rectifier isn't working
    30.34vac between #1 and 28vac same as 28vac and 0v on transformer.

    Quote Originally Posted by jz79 View Post
    I suspect there is also a mistake in your drawing around the pin "1" (or the drawing isn't 100% complete), it is a loop and there can't be any input to rectifier, that is why I put the red cross that might indicate where the error might be and the blue represents the AC coming into the rectifier through those switches/relays
    No mistake in my drawing. Circuit may no be correct, but that is what Is there. Who knows what has been fucked with in the last 40 years..

    Quote Originally Posted by jz79 View Post
    that being said - that normally open relay (that I couldn't understand in the green circle) - look at what is activating that, if it doesn't close, the circuit again makes little sense
    The normally open relay is closed when power is applied to main/motor relay. Motor runs all the time; clutches determine spindle direction.

    Quote Originally Posted by jz79 View Post
    if the fuse on the DC side is 10amp, and we assume 2-3amps current going there under normal circumstances, then the solenoid (we assume it is a solenoid there) coil should measure around 10ohms, more if the current under normal conditions is lower, but there should be resistance there, if it is completely open or resistance is over lets say 200 ohms, then I doubt it can do much work, at 2 amps that circuit will consume 50W, which seems more or less reasonable

    and if the resistance is lower than 2-3ohm (which may read as a short on a multimeter), then there might also be something wrong with that device there, since it would indicate that it would pass current close to the fuse max rating which usually isn't by design
    Just measured resistance F+ to F-- at terminal nearest to device, disconnected from terminal: 12.2 to 12.0 ohms. Maybe device is okay. My wild ass guess would be that it wants about 24vdc. Or possibly 24vac like a rapid feed clutch on another machine(Leblond tracer T lathe)

    There is a copy of a work order from 2013 in the literature that came with machine: "replaced bridge rectifier" "40 amp bridge rectifier."

    I assume that refers to the rectifier on the right. Haven't traced the wires yet, but suspect they are for the rapid controls/pilot light on the carriage.
    dscf1069.jpg

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    ok, let's ignore the schematic for now, when you measure 30V AC is on the input side of the rectifier (red wires - "1" and "28V") is there something on the DC output ("F-" and "47")? If there isn't - it is shot, you can disconnect it and try to test the diodes individually, but I doubt it's worth the effort, there is no way fixing it, just replace it

    the one on the right is a typical silicone bridge rectifier, the brackets are gone, the mark left by the bottom bracket is still visible, so there probably was a selenium one before the repair

    if the rectifier is indeed bad, and you decide to replace it, I'd first give it a manual test - rig up a push button to activate it to see what the effect is before wiring it like it is now, who knows, maybe there was a good reason to disable it...

    oh, and it looks like the violet wire mentioned before is there to replace the cut stub that used to be soldered to the old rec on the right side, but the cut was too short to reach the new rec

    dscf1069.jpg

    it is so relaxing to play detective on someone else's machines on the internet when this happens to one of mine - all I think is - why now dammit!

  10. #28
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    Quote Originally Posted by jz79 View Post
    ok, let's ignore the schematic for now, when you measure 30V AC is on the input side of the rectifier (red wires - "1" and "28V") is there something on the DC output ("F-" and "47")? If there isn't - it is shot, you can disconnect it and try to test the diodes individually, but I doubt it's worth the effort, there is no way fixing it, just replace it

    the one on the right is a typical silicone bridge rectifier, the brackets are gone, the mark left by the bottom bracket is still visible, so there probably was a selenium one before the repair

    if the rectifier is indeed bad, and you decide to replace it, I'd first give it a manual test - rig up a push button to activate it to see what the effect is before wiring it like it is now, who knows, maybe there was a good reason to disable it...

    oh, and it looks like the violet wire mentioned before is there to replace the cut stub that used to be soldered to the old rec on the right side, but the cut was too short to reach the new rec

    dscf1069.jpg

    it is so relaxing to play detective on someone else's machines on the internet when this happens to one of mine - all I think is - why now dammit!

    You are probably right about the former wiring(yellow arrows).

    47 to F-- =.4 to .5 vdc., so I think the rectifier is shot. Suggestion as to a silicon bridge rectifier replacement/substitution???

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    that 12ohm resistance means that the circuit will draw 2-3 amps, so basically any rectifier that looks like the one on the right will work, in that size they usually start at 25-30A and 200V minimum

    here might be a decent candidate - NTE Electronics NTE53016 BRIDGE RECTIFIER FULL WAVE SINGLE PHASE 200V 50AMP 768249550716 | eBay

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    I'll give that a shot. Thanks.

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    Quote Originally Posted by alphonso View Post
    I'll give that a shot. Thanks.
    I get that type from Digi-Key. Always keep a few stashed in the Hell box.

    Same shape but loominum tub/heat-sink.

    ...and 1000 PIV, not 200.

    That way I can use them nearly anywhere, even where spikes exist.

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    Quote Originally Posted by jz79 View Post
    ok, let's ignore the schematic for now, when you measure 30V AC is on the input side of the rectifier (red wires - "1" and "28V") is there something on the DC output ("F-" and "47")? If there isn't - it is shot, you can disconnect it and try to test the diodes individually, but I doubt it's worth the effort, there is no way fixing it, just replace it
    !
    I do not want to say the obvious but when checking make sure the meter is in AC mode when on inputs and set to DC when checking the output.
    Seems simple but I have seen people miss this and in fact have done it myself.

    Normally when these fail they show physical signs which I do not see,
    Anyhoo, easy hockey puck replacement. As said above big PIV is nice to have or other concerns show up during shut off depending on what is out there as these "kick back" power and it has to go somewhere.
    Solenoids are bad enough, big clutches and brakes worse.

    Checked resistance across that device/brake? Is anybody out there?
    The box on line 47 is that a current limiter resistor?

    Perhaps some here are machine control guys and some more electronic circuit guys so views different but the working all the same. (sort of)
    Bob

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    Quote Originally Posted by CarbideBob View Post
    I do not want to say the obvious but when checking make sure the meter is in AC mode when on inputs and set to DC when checking the output.
    Seems simple but I have seen people miss this and in fact have done it myself.

    Normally when these fail they show physical signs which I do not see,
    Anyhoo, easy hockey puck replacement. As said above big PIV is nice to have or other concerns show up during shut off depending on what is out there as these "kick back" power and it has to go somewhere.
    Solenoids are bad enough, big clutches and brakes worse.

    Checked resistance across that device/brake? Is anybody out there?
    The box on line 47 is that a current limiter resistor?

    Perhaps some here are machine control guys and some more electronic circuit guys so views different but the working all the same. (sort of)
    Bob

    Did forget to change meter a few times. Also meter is flakey at times.

    Brake has about 12 ohms resistance. Manual from manufacturer arrived Friday and verifies that the mystery device is indeed an electromagnetic brake.

    Fuse on 47 line.

  16. #34
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    Finally got the rectifier (that jz79 suggested) installed and lo and behold, the spindle brake functions!!!

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