Implementing some kind of feedback would help, although you would need to implement it yourself, the original TM fed the belt or motor sensor back to the console where it was processed, IOW, the MC2100 motor control board does not process it.

My current lathe controller does have encoder feedback, so I'll have to look into it's settings to figure out the low rpm fluctuations. I always just assumed it was the mc2100 causing it. Thank you

 

What are you using for the PWM input control?

 

What are you using for the PWM input control?

I'm using the acorn cnc's own pwm output.

 

Is it right on 20Hz?

 

Yes I have the frequency set to 20hz on the acorn controller and haven't had any problems, as long as I stay under about 90% of max rpm or else the mc2100 just stops. Haven't found a setting in the acorn that limits duty cycle yet. Waiting on some relays to add reverse and maybe braking for tapping.

 

You could use two relays, one for reverse and the other for dynamic braking to shunt the motor when power removed.
I assume you have the motor flywheel removed?

 

I'm using the original DC motor that came with the lathe (PM1127 lathe) so no flywheel, but the chuck does have some weight to it. have the treadmill motor as a back up. I was thinking two DPDT relays for fwd/rev and one DPDT relay in between those and the motor for the braking. I remember seeing a delay setting in acorn for reversing, just hoping the mc2100 doesn't error out when relays disconnect the motor for that brief period. Because if i remember correctly the mc21 has a motor sensing circuit built in.

 

You only need two relays, one DPDT for reverse and one SPDT for OFF & Braking.

 

I am reading around on this board for the MC2100 boards. I have a REV B its problem is that my console will die after 30 to 40 min of use, the Motor will stop a second later. I have checked the Pin1 & 2 on HD2 that go to the console and it will work fine, but flicker and the voltage will drop to 0.2v dc until I unplug and plug back in to the mains. I have replaced the 10,000 caps with no change. I assume there is something failing with the LV system, but I don't know what component to replace next. or if I could wire the console independently to a power supply to reduce the load on what is failing. any advise would be appreciated.

 

The best way to test the board is to isolate it from the console, IOW, just feed 120vac and use a 20hz PWM signal into HD2 1&4.
Also looks like you have the model that has the outboard LV transformer for the 12vdc supply. which you will need.
Most are on board.

 

Good night to you all I am a bit troubled; I have an MC2100LTS-50B Rev main board when power is applied to it on HD2 pins 1 and 2 there is 12vdc output but when a load of 1 amp is supplied to it the output voltage is not constant is it normal for this circuit to behave like that.

 

It is normally unregulated, so it depends on the load and the type of supply yours has, 1amp is around the limit for the normal supply fitted, what is the nature of the load? The console itself?

 

It is normally unregulated, so it depends on the load and the type of supply yours has, 1amp is around the limit for the normal supply fitted, what is the nature of the load? The console itself?

Okay

 

Okay

Yes, it is the console.

 

I am reading around on this board for the MC2100 boards. I have a REV B its problem is that my console will die after 30 to 40 min of use, the Motor will stop a second later. I have checked the Pin1 & 2 on HD2 that go to the console and it will work fine, but flicker and the voltage will drop to 0.2v dc until I unplug and plug back in to the mains. I have replaced the 10,000 caps with no change. I assume there is something failing with the LV system, but I don't know what component to replace next. or if I could wire the console independently to a power supply to reduce the load on what is failing. any advise would be appreciated.

The pics show a MC2100 using an external bias transformer, which is responsible for console power. I am confused as to why a console is connected if you are supplying a PWM externally? The return speed signal lives on the "hot" side of the board, and watches a reed switch at the front roller for timing checks. This then goes into the Cypress IC (CPU) and back out thru an opto to the console board via the console connector. The console is usually responsible for regulations and calibrations although I have seen controllers with CPU libraries programmed for regulations. Some consoles also default to cool-down or shut off after "xx" minutes, but they usually will not go dark or lose all console power. Sounds like source supply possibly? Good Luck....

 

he

Details of MC2100ELS-18W repair
To maintain this excellent knowledgebase of MC2100 information here's my contribution on fault-finding and repairing an MC2100ELS-18W pcb (230Vac version).
Firstly, thanks to JohnnyBeGood who posted an excellent reverse-engineered schematic of this version of the MC2100 here. There were some minor updates subsequent to his initial post. During my fault-finding and repair efforts I came across some discrepancies between my version of pcb and his original schematic - see my separate post.
To the details of my faulty board: the fault symptoms on this board were that the LED blinked 8 times then a pause then 8 blinks again soon after I applied a PWM signal. I had removed the PCB from the TM and powered it up on the bench using 230Vac. I also supplied the 20Hz PWM signal using a function generator into the PWM pin HD2/pin4.
(NOTE: if you use a function gen for the PWM input make sure it has sufficient drive capability to source about 20mA. Also ENSURE that you are not over-driving the PWM optocoupler LED - there is only a 22ohm resistor in series with the LED on the board. Limit the function gen output square wave to approx 3V peak, alternatively add a 680ohm resistor in series with your generator's output. Also make sure the DC offset is set so the square wave minimum does not go lower than 0V).
I used a 230Vac 20W bulb across the motor connections - there was no power going to the bulb, only the LED 8 blinks. After quite some fault-finding I found the following problems:

• the IGBT IRG4PC40K had gate shorted to emitter - I replaced with an STGW20NC60VD
• as a precaution I replaced the IGBT driver U10, an IRS2127
• I also replaced the SCR S8025L with a 2N6509G as well as its driver MOC3052

None of the above solved the problem, the LED still blinked 8 times repeatedly. Further debugging finally revealed another problem. Resistor R52 (1Mohm just below the right hand big cap in the photo) was open circuit and prevented the uC from detecting the HV bus voltage at the cathode of SCR Q3. View attachment 242509
This was the root cause of the 8 blinks - no information that I could find on the interweb pointed to this fault code or its cause. So this is the fault code for absence of HV bus voltage or faulty HV detector circuit. Replacing R52 as well as the IGBT fixed the pcb. The bulb brightness now varies as I adjust the PWM on the function gen.
Next - re-install and connect to motor and upper control pcb, and calibrate the speed pot. I will report any further findings here.
Hopefully this will be of use to others down the line.

Details of MC2100ELS-18W repair
To maintain this excellent knowledgebase of MC2100 information here's my contribution on fault-finding and repairing an MC2100ELS-18W pcb (230Vac version).
Firstly, thanks to JohnnyBeGood who posted an excellent reverse-engineered schematic of this version of the MC2100 here. There were some minor updates subsequent to his initial post. During my fault-finding and repair efforts I came across some discrepancies between my version of pcb and his original schematic - see my separate post.
To the details of my faulty board: the fault symptoms on this board were that the LED blinked 8 times then a pause then 8 blinks again soon after I applied a PWM signal. I had removed the PCB from the TM and powered it up on the bench using 230Vac. I also supplied the 20Hz PWM signal using a function generator into the PWM pin HD2/pin4.
(NOTE: if you use a function gen for the PWM input make sure it has sufficient drive capability to source about 20mA. Also ENSURE that you are not over-driving the PWM optocoupler LED - there is only a 22ohm resistor in series with the LED on the board. Limit the function gen output square wave to approx 3V peak, alternatively add a 680ohm resistor in series with your generator's output. Also make sure the DC offset is set so the square wave minimum does not go lower than 0V).
I used a 230Vac 20W bulb across the motor connections - there was no power going to the bulb, only the LED 8 blinks. After quite some fault-finding I found the following problems:

• the IGBT IRG4PC40K had gate shorted to emitter - I replaced with an STGW20NC60VD
• as a precaution I replaced the IGBT driver U10, an IRS2127
• I also replaced the SCR S8025L with a 2N6509G as well as its driver MOC3052

None of the above solved the problem, the LED still blinked 8 times repeatedly. Further debugging finally revealed another problem. Resistor R52 (1Mohm just below the right hand big cap in the photo) was open circuit and prevented the uC from detecting the HV bus voltage at the cathode of SCR Q3. View attachment 242509
This was the root cause of the 8 blinks - no information that I could find on the interweb pointed to this fault code or its cause. So this is the fault code for absence of HV bus voltage or faulty HV detector circuit. Replacing R52 as well as the IGBT fixed the pcb. The bulb brightness now varies as I adjust the PWM on the function gen.
Next - re-install and connect to motor and upper control pcb, and calibrate the speed pot. I will report any further findings here.
Hopefully this will be of use to others down the line.

thank you for the contribution;
i have the same issue, motor won't run and led 8 times blinking
i changed IGBT, SCR and it's driver MOC3052 but no voltage in pin 4 of the optocoupler going to SCR gate
all resistors and capacitors are ok
i need starting sequence if somebody have
i'm looking for advices

 

Hello everyone, to start a big thank you to this Forum and to all those who give their help. I uploaded the MC2100ELS schematics and really thanks for that. Mine broke down for the second time and it's the same breakdown. Resistor R24 is again hs. Before the resistor burns, my socket fuse (20A) cuts a few times. There is, for me, too much current consumption. I checked capacitor C7 (visually and with an ohm-meter), diode D5 and fuse F1, everything seems OK. If anyone could advise me that would be great. Thank you so much.

 

If it is the R24 511k 1%, on my schematics, which are the one posted here in the forum, it is just a sensing resistor for the micro and does not normally carry any significant current?

 

Hello, no it's 56 ohms on the schematic. I join him here. THANKS.

 

…an example photo (it's not my MC2100 but it's the resistor at the end of the red arrow) THANKS.