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  1. #1
    Join Date
    May 2017
    Posts
    17

    JP-382A schematic.

    Hi Guys, I have a problem with the 5v rail on a JP-382a board, it's reading 1.1v which is way off. if i remove the LPT plug it drops to 0 volts Does any one have a spare board or a schematic for it.

  2. #2
    Join Date
    Mar 2007
    Posts
    2083

    Re: JP-382A schematic.

    Hi Snakips

    the 1.1V must be from the printer port

    it would help to have photos showing all of the two sides of the PCB
    if the photos are clear enough it may be possible to reverse engineer the board as I've done a few times

    it looks like there is a fuse holder on the board

    Attachment 362404

    if a fuse has blown , I'd check for short circuits

    I'd expect a switch mode regulator has been used like the LM2576S used on the this TX14175 board

    Attachment 362406

    Click image for larger version. 

Name:	tx14175 switching 5v  regulator.jpg 
Views:	60 
Size:	93.6 KB 
ID:	362408

    John

    PS

    another board I reverse engineered to see why it didn't work as expected
    another classic Chinese board with design errors

    Attachment 362410
    Click image for larger version. 

Name:	chinese breakout board.jpg 
Views:	89 
Size:	161.4 KB 
ID:	362414
    Attached Thumbnails Attached Thumbnails Chinese - Schematic.pdf  

  3. #3
    Join Date
    May 2017
    Posts
    17

    Re: JP-382A schematic.

    Quote Originally Posted by john-100 View Post
    Hi Snakips

    the 1.1V must be from the printer port

    it would help to have photos showing all of the two sides of the PCB
    if the photos are clear enough it may be possible to reverse engineer the board as I've done a few times

    it looks like there is a fuse holder on the board



    if a fuse has blown , I'd check for short circuits

    I'd expect a switch mode regulator has been used like the LM2576S used on the this TX14175 board





    John

    PS

    another board I reverse engineered to see why it didn't work as expected
    another classic Chinese board with design errors




    Hi john, Thanks for the response.
    The fuse holder is on the 24v line, I've checked all of them they are ok. The Spindle board is working ok turns spindle on and speed works (sort of not controlled by soft ware) all limit switches are working right back to the pc software. X,Y,Z steppers not responding, controlled by port pins X,step 2,dir 3. Y, step 4, dir 5, Z,step 6,dir 7. I've confirmed pins 3 and 5 are active and working but can't see any activity on the step pins 2 and 4
    Pin 1 on the lpt port seems to enable the controller. off to buy a lpt port pci card in case mine has been damaged, and going to reinstall mach3. failing that i'll take some more pics
    There is a reg on the back TD1507-5L which has an on/off on it's pin 5, which i suspect is going to lpt pin 1.

  4. #4
    Join Date
    May 2017
    Posts
    17

    Re: JP-382A schematic.

    Quote Originally Posted by Snakips View Post
    Hi john, Thanks for the response.
    The fuse holder is on the 24v line, I've checked all of them they are ok. The Spindle board is working ok turns spindle on and speed works (sort of not controlled by soft ware) all limit switches are working right back to the pc software. X,Y,Z steppers not responding, controlled by port pins X,step 2,dir 3. Y, step 4, dir 5, Z,step 6,dir 7. I've confirmed pins 3 and 5 are active and working but can't see any activity on the step pins 2 and 4
    Pin 1 on the lpt port seems to enable the controller. off to buy a lpt port pci card in case mine has been damaged, and going to reinstall mach3. failing that i'll take some more pics
    There is a reg on the back TD1507-5L which has an on/off on it's pin 5, which i suspect is going to lpt pin 1.
    AH Progress, The JP-382A board is out, Have fitted a new pci parallel port card in pc and reinstalled mach3 , still had a problem. now resolved. Back to the JP board, have plugged it in on my work shop pc, and running on a 24v current limited supply no heat sink or load, The TD1507 reg is working ok it's on/off pin is gnd not switched, o/p bang on 5 volts, found a 5volt DC to DC isolation converter near the in put port which has 5 volts going in and 0.8 going out. Just about to remove it and test on it's own.

  5. #5
    Join Date
    May 2017
    Posts
    17

    Re: JP-382A schematic.

    Thanks John, you were dead right, the dc to dc converter had blown, I took it out and bench tested it, no output the voltage was coming from the pc's port. The JP-382A port is powered by the dc to dc 5volt, the pins connect to a 4k7 sil pull up then into a 7407 hex inverter, which pulls down the cathodes of the 6 4N26 opto's, two for each axis, step and direction. I've found an RS replacement TMA0505S which i can get tomorrow. Will post a schematic of what i've traced out so far it might help some one else.

  6. #6
    Join Date
    Mar 2007
    Posts
    2083

    Re: JP-382A schematic.

    Hi Snakips

    thats good news
    you have found the fault and can buy the replacement parts to repair your board
    the breakout board is one I've not seen for sale

    John

  7. #7
    Join Date
    May 2017
    Posts
    17

    Re: JP-382A schematic.

    New DC DC converter fitted, still have a problem with output control. but all seems to be working on bare board bench test using a different pc, schematic so far just the output driver stages to go.
    Attached Thumbnails Attached Thumbnails main 1.jpg  

  8. #8
    Join Date
    May 2017
    Posts
    17

    Re: JP-382A schematic.

    Click image for larger version. 

Name:	main 1.jpg 
Views:	41 
Size:	68.0 KB 
ID:	363230

  9. #9
    Join Date
    Jan 2023
    Posts
    2

    Cool Re: JP-382A schematic.

    Hi Snakips.

    Could you share those images in a better resolution?
    Maybe a pdf file?

    Regards,

    Márcio Ribeiro

  10. #10
    Join Date
    Jan 2023
    Posts
    2

    Re: JP-382A schematic.

    Here you are a small circuit diagram taken from a JP382A I'm using.
    Attached Files Attached Files

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