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Spindle Motor PCB F1A112000 not working correctly


christoph.nissl@...
 

Dear all,
I've got a Emco F1 CNC Woodworker. It runs well so far, but the spindle motor controler makes some trouble. The spindle is turning and its also responding to the speed potentiometer, but there is almost no Power. The Spindle is turning higher than expected, but will lose speed immediately if there is any load applyed. I suggest, that the current should rise to apply more power, but this is not working any more. I still have a second F1A112000 PCB which is working like expected, but I would like to repear the broken one for spare.
Does anyone of you have had such a phenomen already? Does maybee anyone have the circuit diagram of the spindle motor controlerboard? This would help me a lot to find the error.

Thank you very much!

BR
Chris


Dieter
 

Hello Chris,

A diagram is in the Files section: Emco5cnc Original circuits 2 files Retraced circuits for the spindle motor drive and speed readout.

Dieter


christoph.nissl@...
 

Hello Dieter,
thank you very much for your reply. I found the document. It's a bit confusing for me. I'm only doing a bit of electronics for my hobby. I'm not a professional and really far far away from what you are doing here ;-). But I've got one working electronic for spare, so I can make measurements on the good one to compare values.
 
I thought I would try this way:
1. re check both fuses.
2. I suggest the failure could be in the current and/ or voltage sensing part, because the spindle does stall fast on low torque. With the good pcb the spindle speed stays stable on different loads. Also it looks like the spindle turns faster at all speed settings (speed knob) with the broken pcb compared to the working one. So I try to measure the spindle supply voltage with the oszi. I'd like to know the exact supply voltage at low and high speed and also the voltage profile. I guess, there could be any difference which could show the next steps.
3. If step 2 shows nothing, I would try to change all capacitors and maybee the two LM324. I guess capacitors are the only parts on this pcb which will break after a long time.
 
That's the plan for now. I hope It's not the totally wrong way. I show my results as soon as I had time to measure.
 
BR
Chris


Dave Leer
 

Chris, I have an EMCO F1 Woodworker also. I am going retro. As far as I know, the only thing that is wrong with the controller is that the #1 button on the key
pad has come off. I plan to get rid of the controller. I am in Cincinnati,OH, USA.
Dave


On 11/22/2020 4:41 PM, christoph.nissl@... wrote:
Dear all,
I've got a Emco F1 CNC Woodworker. It runs well so far, but the spindle motor controler makes some trouble. The spindle is turning and its also responding to the speed potentiometer, but there is almost no Power. The Spindle is turning higher than expected, but will lose speed immediately if there is any load applyed. I suggest, that the current should rise to apply more power, but this is not working any more. I still have a second F1A112000 PCB which is working like expected, but I would like to repear the broken one for spare.
Does anyone of you have had such a phenomen already? Does maybee anyone have the circuit diagram of the spindle motor controlerboard? This would help me a lot to find the error.

Thank you very much!

BR
Chris


Dieter
 

Hi Chris,

Did you checked the RV2 and RV3 trimmers, I made some tests on my machine to check for your problem and they have great influence on behavior of the motor.
The RV2 has greatest effect, if wrong trimmed the motor became unstable when loaded. RV3 changed the speed a little.
Turn both trimmers in midst position to start.
Perhaps the previous owner had moved them or the they makes "bad contact", verify with an Ohmmeter if you reach the specified values when turning in each extremity.
When turning slowly the value must increase/decrease linear without "tremble", for this it's bests to use an analog instrument.
The sliders may be oxidized, turn them back and forth multiple times to "revitalize" them. Damp storing from previous owners is often a problem, I had bad connectors
and rusty surfaces.
Save the trimmer positions of your good board with a marker in case of accidentally moving them.

Has your machine 1 or 2 index plates? If 2 your controller has an NE555 and some more parts, a trimmer and optocoupler which could make problems.

The values for some parts certainly differ from the circuit diagram, it's retraced from a 230 V controller for Europe without the NE555.
The 115 V motor draws double current as the 230V type, so the current control circuit must use different values.

Dieter


christoph.nissl@...
 

Hi Dieter,
sorry for my late answer and thank you very much for your effort! I was not able to work on the emco before now.
 
Yesterday I had time to have a look at it:
Your hint with the poti was good. I do not have an analog multimeter, but tryed to check them with the digital one. For me they seemed to be ok. Attachted there is a picture of the pcb. I marked the pots. Actually there are four pots on the pcb. Two normal ones (1/ 2), one fine trimmer (4) and the one to set the speed. I think the fine trimmer is not in the curcuit diagram isn't it?
As I had a closer look to the pcb I saw, that the pot 2 was already resoldered because there was some flux on the backside. Also LM324 No. 2 was resoldered. There were two different types of LM324 in it. One LM324J and one LM324N.


I decided to desolder both LM324. I soldered sockets and ordered new LM324. I will try LM324AN type. Seems to be the one with closer tolerances.
 
Before disassembling I did some measurements with the oszi for refference with the good and bad pcb. I assumed there would be more difference between them. I used a 1:100 probe. I had to use it on +-20V setting, because there were extremly high voltage pulses of more than 1000V on both pcbs. Thats the reason why the resolution is not as good as it should be.
 
Attachted you'll see the good PCB working at lowest speed without load. I connected the probe at the back of the maschine, at the closest screw terminal to the motor. The frequency is 100Hz which I assumed comes from the double net frequency by using rectifyers. First the Voltage jumps up to ~120V, is falling down to ~16V and then rising a bit at half period time:



And here comes the broken one:
The machine setup was the same like above, lowest speed, no load on the spindle. The mayor differences are the higher voltage level, peak at ~190V compared to ~120V and also drop to ~50V compared to ~16V.
Also what's hard to describe is, the good pcb produces a clear view on the scope. The voltage on the bad one is much more volatile, as you can see a bit on the pictures.


Whats the result so far?
- The higher voltage of the broken pcb corelates with the higher rpm at low speed what I assumed.
- I hoped of a more significant difference between both pcbs on the scope.
 
I do not really know how to continue, but my next step will be the exchange of the LM324 like I described above.
I will give you the result of the LM324 as soon I received them.
 
Thank you very much.
 
BR
Chris


Chile Bike
 

Sadly Chris, unless the 324's were faulty it won't make any difference. The point of an opamp is that it's key characteristics - gain, offset- make its performance a function of the surrounding components. I changed them on the board I gave to Jim purely as that was easier than testing them after I'd zapped the thing, and put in some random quad parts that I had in stock, and they were fine. The quality of the pcb is such that you are more likely to get a solder fault than a component failure. For the record, the times I zapped the board were:
Only runs at min speed - The cap across the speed pot went s/c - changed , all good.
No workee at all - Reversed the motor direction too quickly - exit the thyristors. I shoved some 1200v8a parts in there , checked the diodes, all good.
More no workee - Finally, the -12v zener died the death, replaced with 7912. Zeners go s/c. I don't use them in my designs. You should find +-12v on those fat boy caps in the middles, as well as +20 or thereabouts on the fat Spaniard, Large Juan. I see yours does not have very fat boy caps. Budget.
Fixed all that, changed it to 120v operation & gave it to Jim. Beer and medals all round.
One of those presets sets the motor torque control, too high, the speed will sag with torque, too low, the motor speed will hunt.
I would council, however, to bin that thing and use the DC motor controllers on eBay. They are a million times better. The Emco thing uses a bridge rectifier arrangement with SCR's on half the limb, consequently, the motor is getting 100hz 'DC' The ebay thing uses a much higher frequency PWM. Result, much quieter, motor goes to 0 RPM, all the limits are settable, all the inputs are isolated. And the build quality, for 45 quid, is exemplary. If I'd designed & made that, I'd be proud of it. You can cut the speed display off the board & still run that, it is entirely seperate. If you want to know which one I used, ask. POP to use.
Don't electrocute yourself with that thing. It's not worth it.
sdk

On Monday, 28 December 2020, 21:29:32 GMT, <christoph.nissl@...> wrote:


Hi Dieter,
sorry for my late answer and thank you very much for your effort! I was not able to work on the emco before now.
 
Yesterday I had time to have a look at it:
Your hint with the poti was good. I do not have an analog multimeter, but tryed to check them with the digital one. For me they seemed to be ok. Attachted there is a picture of the pcb. I marked the pots. Actually there are four pots on the pcb. Two normal ones (1/ 2), one fine trimmer (4) and the one to set the speed. I think the fine trimmer is not in the curcuit diagram isn't it?
As I had a closer look to the pcb I saw, that the pot 2 was already resoldered because there was some flux on the backside. Also LM324 No. 2 was resoldered. There were two different types of LM324 in it. One LM324J and one LM324N.


I decided to desolder both LM324. I soldered sockets and ordered new LM324. I will try LM324AN type. Seems to be the one with closer tolerances.
 
Before disassembling I did some measurements with the oszi for refference with the good and bad pcb. I assumed there would be more difference between them. I used a 1:100 probe. I had to use it on +-20V setting, because there were extremly high voltage pulses of more than 1000V on both pcbs. Thats the reason why the resolution is not as good as it should be.
 
Attachted you'll see the good PCB working at lowest speed without load. I connected the probe at the back of the maschine, at the closest screw terminal to the motor. The frequency is 100Hz which I assumed comes from the double net frequency by using rectifyers. First the Voltage jumps up to ~120V, is falling down to ~16V and then rising a bit at half period time:



And here comes the broken one:
The machine setup was the same like above, lowest speed, no load on the spindle. The mayor differences are the higher voltage level, peak at ~190V compared to ~120V and also drop to ~50V compared to ~16V.
Also what's hard to describe is, the good pcb produces a clear view on the scope. The voltage on the bad one is much more volatile, as you can see a bit on the pictures.


Whats the result so far?
- The higher voltage of the broken pcb corelates with the higher rpm at low speed what I assumed.
- I hoped of a more significant difference between both pcbs on the scope.
 
I do not really know how to continue, but my next step will be the exchange of the LM324 like I described above.
I will give you the result of the LM324 as soon I received them.
 
Thank you very much.
 
BR
Chris


christoph.nissl@...
 

Hi Bike,
thank you very much for your meassage. I'm a fan of using the original Emco stuff as far as possible. If It's not possible, it is so. I hope that one of the 324 is broken, but in case it's not I would prefer the ebay DC Controller you mentioned. Can you please give me a hint which one would work best for the emco f1. I've got the Woodworker which has a 180V Motor.

BR
Chris


Chile Bike
 

Helo Chris,
Yes, I have noted in this space the determination to 'keep things original'. I'm a little baffled by this, as the strength of a machine tool is in it's mechanical implementation. Given I was designing electronics with 6800's nearly 30 years ago, the idea of the merit of ancient electronics having a value to the machine being greater than replacing them by the massive advantages of modern electronics I find bemusing. Coding in machine code - I started with that all those years ago - won't get you far with an Arm Cortex, but the Arm part will take you far further than 1980's electonics. And for a lot less money. Let's not even think about EMC. Look at that motor control board - Bridge control, shunt zener regulators, FR2 PCB, bead tants, no solder mask,oh my. And it doesn't even go to zero RPM and goes bang if it gets an external problem. There won't be an Antiques Roadshow with a celebrity dealer saying 'Hmmm, a genuine Emco, using the original control circuitry, worth a fortune'. There's much more chance of it being in the scrap because the electronics have failed. The results, the work it does, the things it makes validate the machine. The thing I have, a C5, is a toy, certainly compared to the other machines I have, but it can do things they can't, despite their 20x weight. If it gives me the finish and the repeatability I need, it lives. Else, it's toast. I clatter around on truly ancient British motorcycles, but they have new Mikuni carbs, precision electronic ignition, revised charging systems and hydraulic clutches. Because they have to work, not be a 'concours' museum piece at the side of the road.
Enough of that.
https://www.ebay.co.uk/itm/AC180V-260V-Input-DC220V-Output-8A-adjust-PWM-DC-Motor-Speed-Controller-Driver/112212401393
is the animal I bought, there's a bunch of them out there. They are available in 110v input as well, and the max motor voltage is settable, as is the current. This was listed as 220v output but the setting to 180v is simple. I managed to get the instruction manual to tell how, press a few buttons. Who actually makes these things heaven only knows, but 'GoldenBrightSunnyDay' or whoever seem to sell the same thing. The inputs are isolated, so the pot isn't live, nor are the start/stop and direction switches. And the motor is quiet, and goes to zero. Fourty Five quid? Enough to make an electronics manufacturing man weep.
sdk



On Wednesday, 30 December 2020, 08:28:19 GMT, <christoph.nissl@...> wrote:


Hi Bike,
thank you very much for your meassage. I'm a fan of using the original Emco stuff as far as possible. If It's not possible, it is so. I hope that one of the 324 is broken, but in case it's not I would prefer the ebay DC Controller you mentioned. Can you please give me a hint which one would work best for the emco f1. I've got the Woodworker which has a 180V Motor.

BR
Chris


Chile Bike
 

I forgot to say - you get rid of that wretched choke, too.
sdk


On Wednesday, 30 December 2020, 08:28:19 GMT, <christoph.nissl@...> wrote:


Hi Bike,
thank you very much for your meassage. I'm a fan of using the original Emco stuff as far as possible. If It's not possible, it is so. I hope that one of the 324 is broken, but in case it's not I would prefer the ebay DC Controller you mentioned. Can you please give me a hint which one would work best for the emco f1. I've got the Woodworker which has a 180V Motor.

BR
Chris


Richard Engbersen
 

Hi @administrator of this EMCO group.

Could you please be so kind nd add to the subscriptions: Cattanello@...

This is my friend Marco Cattaneo from Switzerland.
He has bought two CNC machines EMCO PC mill 50 / EMCO PC lathe 50) from another friend of me Mr. Giuseppe Morvillo in Napoli in may 2019.
He is very much interested to do a retrofit on his machines.
Can you please help me to add him to this group, because i have no idea how it works after we migrated from the Yahoo group.

Last but not least: Happy New Year 2021 for all global EMCO users in this nice group !!

Thanks you very much (on behalf of Marco) & best regards,
Richard

Virusvrij. www.avg.com

Op do 31 dec. 2020 om 14:45 schreef Chile Bike via groups.io <chile_bike=yahoo.com@groups.io>:

I forgot to say - you get rid of that wretched choke, too.
sdk


On Wednesday, 30 December 2020, 08:28:19 GMT, <christoph.nissl@...> wrote:


Hi Bike,
thank you very much for your meassage. I'm a fan of using the original Emco stuff as far as possible. If It's not possible, it is so. I hope that one of the 324 is broken, but in case it's not I would prefer the ebay DC Controller you mentioned. Can you please give me a hint which one would work best for the emco f1. I've got the Woodworker which has a 180V Motor.

BR
Chris