Home Switch Problem

[Kev2960]

Ok I'll get a photo, thanks for your help

[Kev2960]

Good morning, here is a photo of the underside of my bob;
Kev

[m_c]

So if the 24V LED is lighting up, and you've got no voltage at the top left pin on the opto's, then looking at that, the fault can only be the throughhole/via.

If you connect 24V to the board, looking at the front of the board, follow the track from the 24V LED to the via at the T-junction in the track. You should get 24V there?
If you do, then flip the board over and see if you still get 24V on the opposite side of the via.
If you do, then follow the track up and check to see if you get 24V at the optos.

If it is a faulty via, applying pressure when you probe could be enough to re-connect it. If that is the problem, the easy option is to put a little bit wire through it (drill it out slightly if needed), and solder it on both sides, and that should reconnect both sides of the PCB.

[Kev2960]

WOW i have no idea what you've just said !
This is a bit out of my depth, what's the via. if I was to send you the board could you repair it ? all costs paid by me

[john swift]

Hi Kev

using the photo's from post 3 and post 32

I have traced part of the supply circuit powering the opto-isolators




the track from the opto-isolators starts of on the underside of the board
then near to the 24V LED passes through a "via" (a plated through hole)and

then another "via" next to the missing B axis connector

the track ends at the + connector of the capacitor next to the LM317 regulator
the photo is not clear enough but I expect the capacitor + terminal is connected to the metal tab on the LM317 which is connected to the regulator output

the 1800 ohm and two 300 ohm resistors set the LM317 output to 10V

looking closer at the LM2576 switching regulator it has -5.0 at the end of its part number indicating its the 5V version
( LM2576S-5.0 = 5v ouput )

if a Via is open circuit the copper pads can be cleaned and a copper wire passed through and soldered to remak the connection

since the "24V LED" lights the only Via to check is lext to the LED

John

PS

check there is continuity from the limit switches 5 pin connector common terminal and the DC power in negative

[Kev2960]

Hi John the meter readings are all zero on that side switches open or closed

[john swift]

Hi Kev

I think a simple tester would prove if the breakout board is working




John

[Kev2960]

John can I send you the board ?
You know way much more than I do about this kind of stuff

[john swift]

Hi Kev
OK
PM sent

[m_c]

John, I suspect you've got the optos in the wrong order.

If you look at the traces on the top side, I'd say the top opto is P10, and it's track runs down the outside of the limit switch connector to the E-Stop connector. The tracks of the other 4 optos seem to match up nicely with the Limit Switch connector, and I wouldn't expect the bottom opto track to run the way it does if it was going to the E-stop connector.