Seig C3 CNC spindle problem

[Leadhead]

Need help please, with my Seig CNC. This is an early conversion from Arc. Had problems for some time with the front guard micro switch. So took out the switch and coupled the wires together. Solved the problem and all was well until I accidentally dropped the wires and shorted the main fuse. I can now hear the relay clicking in and out as normal but no spindle movement. If you have any inclination towards a possible solution, I would be extremely grateful.

[Chaz]

There might be a main power fuse blown that feeds the spindle (as well as a fuse in line near the spindle's drive). Are you getting power to the spindle drive?

[Leadhead]

Chaz - No just getting the normal audible click on and click off. This is the model with the separate 12v power supply at the back of the column. Having my sparkbuddy check it out in the morning.

[john swift]

have you asked Ketan @arc eurtrade

Photos of the speed control board and CNC interface will be useful

my mini lathe for example has a seig FC250 PWM speed control board with 2 FET's as the control devices
the board has has two relays that form a no-volt release and interlock that forces you to start at minimum speed

later machines have a XMT2325 speed control that uses two thyristors as the control devices that are part of a controlled bridge rectifier

once the various boards have been identified it will be easier to fault find

John

[Leadhead]

John - Thanks for help. I will take some photo`s this morning,

Rod

[Leadhead]

John - Here is photo of board. The two blue wires next to the central small white box are the ones I shorted. The card is marked SEIG MACHINE zz0070201A 24671

[john swift]

I have not found an exact match but this PDF wiring diagram for a
110V mini lathe gives you a basic wiring diagram
PDF diagram
24672

for the CNC conversion
the speed control potentiometer that is normally connected to terminals p1 to p3 has been replaced by
a DC control voltage connected to p1 & p2



without the circuit diagram of the speed control board
I can not guess what the blue wires are connected to and
what possible damage to the board could of happened to the board

24673

if the under side of the PCB looks OK with no blown tracks
it will be possible to bench test the board using a 100W bulb as a dummy load in place of the motor and a potentiometer connected to P1 to P3
NOTE - all the board & the wiring to the potentiometer will be live !!!

repairing my CL300m lathes speed control board
https://www.model-engineer.co.uk/forums/postings.asp?th=38809&p=1

John

PS
found it
the board is a XMT-2360

24674

[Leadhead]

John - Thanks, the board is XMT 2360. The two blue wires are connected to the green chuck guard switch you have indicated. There are currently 3.6V across the terminals.

[john swift]

Les has details of the XMT-2360 on his web site
http://lesjhobbies.weebly.com/uploads/2/8/3/1/28311931/pcb_speed.pdf

if your lucky R17 on page 2 has gone high resistance when terminal K3 shorted to earth

terminal K4 shorting to earth will be of a problem

John

[Leadhead]

John - If the R17 has gone high. Is there anything I can do?
Rod

[john swift]

looking at the circuit diagram I linked to

this a simplified diagram of the low voltage supplies to the control circuit

24675

R17 is the large resistor on the board

its value is 15 K (15000 ohms)
in parallel with a 100K resistor that gives you a total of 13K

if you get more than 13K then R17 will need replacing
has R17 changed colour ?

24676

the resistors drops the rectified mains down to 22V at terminal K4 is linked to K3

with K3 & K4 open circuit I would of expected you to have 200V DC

if terminal K4 was shorted to earth
a number of semiconductors will need checking
starting with Z1 the 22V zenner and the 78L12 regulator IC

John

[Leadhead]

The machine in question is in fact my X3 mill and not the C3 lathe.