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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.http://www.cnczone.com/forums/attach...d=362358&stc=1
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
Attachment 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
Attachment 362414
Quote:
Originally Posted by john-100
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.Quote:
Originally Posted by Snakips
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.
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
http://www.cnczone.com/forums/attach...d=363232&stc=1New 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.http://www.cnczone.com/forums/attach...d=363228&stc=1
Hi Snakips.
Could you share those images in a better resolution?
Maybe a pdf file?
Regards,
Márcio Ribeiro
Here you are a small circuit diagram taken from a JP382A I'm using.