# SIEG C6 Board photo



## ProfessorBean (Jun 11, 2020)

Hi guys, first post here.
I’ve just got my first lathe. I got it cheap because there was a problem with the motor not spinning. After a few hours of investigation I’ve found that the problem is on the board. The middle chip on the back is damaged. In order to replace the chip I need to know what the number on the back is. Since it’s damaged, I can’t see the number. Only partially

Does anybody happen to have a photo of the board? Or know the number. The board number is XMT-2380.

Thanks for any help. 


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## markba633csi (Jun 11, 2020)

Is the chip burned/exploded or damaged some other way, like physically smashed?  If the former, there may be more wrong than just the one chip-
The power supply should be checked before replacing it, if you can id the chip and buy it (AliExpress?)
Check online you might be able to find a schematic diagram with part #s
-Mark
If you are versed in reverse engineering it may be possible to deduce the type of chip by studying the surrounding circuitry
It may help if you can post some close up views of the board-  I might be able to point out some clues for you
Is this a dc brush type motor or brushless dc?


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## ProfessorBean (Jun 11, 2020)

markba633csi said:


> Is the chip burned/exploded or damaged some other way, like smashed? If the former, there may be more wrong than just the one chip-
> The power supply should be checked before replacing it, if you can id the chip and buy it (AliExpress?)
> Check online you might be able to find a schematic diagram with part #s
> -Mark
> If you are versed in reverse engineering it may be possible to deduce the type of chip by the surrounding circuitry



Hi mark, thanks for the reply.
It’s hard to say what has happened as it doesn’t look exploded/burnt, but there is a square of plastic missing off the back, in the centre. The square is around 2mm. 
I’d doubt it could have been impacted by anything, as it is quite hidden, as you’d imagine. 

I won’t lie, electronics aren’t my thing so I am open to anything you may suggest. Once I determined the board was faulty I took it to a local specialist who discovered the damaged chip. If I get the required number, he is going to order and replace for me. 

The only schematic I could find online was for a smaller lathe and the numbers on that didn’t correspond to the last remaining digits that I could make out on my chip. 

I would post a photo but I’m not allowed, because I’m new I believe. 

Thanks again. 


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## ProfessorBean (Jun 11, 2020)

To answer your edited part, the motor is DC brushed. The motor is fine as I have powered it, independent of the board.

Also, I can’t post photos 


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## ProfessorBean (Jun 11, 2020)

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## ProfessorBean (Jun 11, 2020)

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## JRaut (Jun 11, 2020)

Are you referring to one of those chips directly attached to an aluminum heat sink?

If this is the main power supply board, perhaps it's a rectifier diode. If it's some sort of motor driver board, perhaps a mosfet.

Either way, if you are talking about one of the heat-sinked chips, the other chips similarly heat-sinked are probably identical, and you could pull a number off one of them.


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## JRaut (Jun 11, 2020)

(Ah, I sent my previous post as you were in the process of uploading more photos. I see the damaged chip now.)

As @markba633csi suggests, replacing that chip probably won't cure what ails ya. That chip likely exploded due to a malfunction in some other portion of the board. Probably on the power delivery side of things.

If I were you, I'd be searching eBay and the like for a complete replacement board, rather than trying to fix this one. Sure, it probably _could_ be fixed, but sourcing a full replacement will probably be cheaper (if you're paying someone else to figure out what's wrong), easier, and faster.


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## ProfessorBean (Jun 11, 2020)

If you look at the photos on the back of the side with the heat sinks, you can see the damage to one of the black chips


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## ProfessorBean (Jun 11, 2020)

Thanks JRaut,

It’s not what I want to hear but you’re probably right. 

The cost for the guy to put me a new chip on £30. The cost for a new board, £200.

But if you think there may be another problem that caused it, it would be £30 wasted if it pops again 


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## markba633csi (Jun 11, 2020)

OK, what I believe you have there is an SCR controller similar to the KB electronics designs.  Probably several solid state components are damaged. The chip in question is most likely a LM324 quad op amp, but something else failing on the board blew it up.  You would need to check all the power devices and the power rectifiers D16 thru D19.  You might be better off trying to find a replacement controller (like the aforementioned KB brand) You can often find them on Ebay for less than 100$ US
-M


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## ProfessorBean (Jun 11, 2020)

Thanks a lot for taking the time to help me on this.

You obviously know what you are talking about so I’ll give up on this board now. It’s worrying that the “specialist” didn’t make the same points as you. He basically said we can change the chip and all would be good. 

Do you happen to know if the controllers you mentioned would be a relatively straight swap?

Also, while I have you expert eyes on the job, I came across another way to do it without the board.

What do you think of getting it running by using a simple rectifier and a voltage regulator as below? Could this be bad for the motor?


ICQUANZX AC 220V 4000W High Power SCR Electronic Voltage Regulator Governor Dimmer Thermostat Speed Controller 





						ARCELI AC 220V 4000W High Power SCR Electronic Voltage Regulator Governor Dimmer Thermostat Speed Controller: Amazon.co.uk: DIY & Tools
					

ARCELI AC 220V 4000W High Power SCR Electronic Voltage Regulator Governor Dimmer Thermostat Speed Controller: Amazon.co.uk: DIY & Tools



					www.amazon.co.uk
				




Thanks again


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## DAT510 (Jun 11, 2020)

This person repairs the boards for a flat rate of $50 USD.  States he will ship international First Class for an additional fee.









						MINI LATHE - MILL BOARD REPAIR SERVICE
					

Check out this GoDaddy hosted webpage! http://olduhfguy.com.




					olduhfguy.com


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## ProfessorBean (Jun 11, 2020)

Thanks for that. That looks like the guy I need! I’ll keep him in mind when I decide what do do. I wonder how long postage will take with the world the way it is at the moment...


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## markba633csi (Jun 11, 2020)

Hi Professor: Yes you could run the machine from a simple dimmer circuit + bridge rectifier but you would not have good speed regulation under varying loads, which a feedback style SCR controller gives you.  You could also use a variac + bridge
I was going to suggest olduhfguy.com but the shipping could be prohibitive.  I'd offer to fix it for less than 50$ if you were willing to pay the postage to and from the US.  The turnaround time might be an issue because of the pandemic.
The KB brand controllers would be compatible, except for the physical size. Actually they are a little smaller I think.
KBIC-125 is one model I have used- You would need a KBIC-225 for 240 volt mains if I remember correctly
You might contact olduhfguy and ask if he has any extra Seig boards for sale-?  Just a thought


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## ProfessorBean (Jun 11, 2020)

markba633csi said:


> Hi Professor: Yes you could run the machine from a simple dimmer circuit + bridge rectifier but you would not have good speed regulation under varying loads, which a feedback style SCR controller gives you. You could also use a variac + bridge
> I was going to suggest olduhfguy.com but the shipping could be prohibitive. I'd offer to fix it for less than 50$ if you were willing to pay the postage to and from the US. The turnaround time might be an issue because of the pandemic.
> The KB brand controllers would be compatible, except for the physical size. Actually they are a little smaller I think.
> KBIC-125 is one model I have used- You would need a KBIC-225 for 240 volt mains if I remember correctly
> You might contact olduhfguy and ask if he has any extra Seig boards for sale-? Just a thought



I am humbled by the support I’ve received. Thanks so much.

I was just about to take you up on your offer to repair but I believe I have found the board I need on eBay, thanks to you. Would you mind having a look over it and confirming it’s right?
Also, 240v is what I’m on, on this side of the pond. 










						KB Electronics KBIC-225 SCR Chassis Drive, 9432L, 1/50-3HP @ 230VAC 50/60Hz In  | eBay
					

Find many great new & used options and get the best deals for KB Electronics KBIC-225 SCR Chassis Drive, 9432L, 1/50-3HP @ 230VAC 50/60Hz In at the best online prices at eBay! Free delivery for many products!



					www.ebay.co.uk
				





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## markba633csi (Jun 11, 2020)

Yes indeed that would fit the bill, notice the orange tag on the board: there is an additional item you need which is a "horsepower resistor", it is a current sensing resistor that plugs into the board.  KB sells them, I added a link. The ohm value of the resistor depends on the horsepower rating of the motor you use with the controller.  KB has/had a chart online listing those resistors- I'll post it if I can find it
You might want to put a 3AG style fuse holder and fuses on your shopping list as well, not expensive and good insurance- for a 1/3HP 240 volt motor something like 3 amp would be appropriate, between the mains and the controller.
-M
The vendor might/might not provide the HP resistor with purchase of a controller- they should provide a panel-mount potentiometer and some fast-on terminals to connect the unit- ask what is in the package when ordering








						KB Electronics Plug-In Horsepower Resistors, KBIC KBMM KBPB KBCC KBWM KBMD  | eBay
					

KB Electronics Plug-In Horsepower Resistor Selection Chart Motor Horsepower Range. 1/12 – 1/8 1/6 – ¼ 0.7 – 1 0.18 9837 ¼ ½ 1/3 ¾ 2.5. 1/30 – 1/20 1/15 – 1/10 0.3 – 0.5 0.35 9835 - - - - -. 1/50 – 1/30 1/25 – 1/15 0.2 – 0.3 0.51 9834 1/15 – 1/10 1/6 – 1/5 1/12 – 1/8 1/6 – ¼ 0.7 – 1.



					www.ebay.co.uk


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## ProfessorBean (Jun 11, 2020)

markba633csi said:


> Yes that would work, notice the orange tag on the board: there is an additional item you need which is a "horsepower resistor", it is a current sensing resistor that plugs into the board. KB sells them or you can wind your own. The ohm value of the resistor depends on the horsepower rating of the motor you use with the controller. KB has/had a chart online listing those resistors- I'll post it if I can find it
> -M



Ok I will place the order now.
Thanks


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## ProfessorBean (Jun 11, 2020)

markba633csi said:


> The vendor might provide the HP resistor with purchase of a controller- they should also provide a panel-mount potentiometer and some fast-on terminals to connect the unit- ask what is in the package when ordering



I have purchased the unit now, a bargain I think at £38. There appears to be a resistor with it, as on the photo. Not sure what size though, I will ask. My motor is 1hp







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## ProfessorBean (Jun 11, 2020)

800watts is what is on the front of the lathe which I believe is 1hp


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## markba633csi (Jun 11, 2020)

746 watts/ HP at 100% efficiency, but nothing is 100% efficient.  Your motor is probably more like 1/2 to 2/3 HP.  Could even be less, these machinery companies are known for exorbitant exaggeration.
Looks like a potentiometer and terminals are included.  You'll have to purchase the HP resistor separately.  Pick a HP resistor somewhere between
1/3 and 3/4 HP and you should be fine. There is some latitude there. Expect to touch up the adjustments for torque compensation and start-up speed when you get the unit running.
-M


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## Mitch Alsup (Jun 11, 2020)

markba633csi said:


> OK, what I believe you have there is an SCR controller similar to the KB electronics designs.  Probably several solid state components are damaged. The chip in question is most likely a LM324 quad op amp, but something else failing on the board blew it up.  You would need to check all the power devices and the power rectifiers D16 thru D19.  You might be better off trying to find a replacement controller (like the aforementioned KB brand) You can often find them on Ebay for less than 100$ US
> -M



Quad Op Amps blow up because their output got shorted to Ground or to Vdd. There is something else wrong on that board.


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## ProfessorBean (Jun 12, 2020)

markba633csi said:


> 746 watts/ HP at 100% efficiency, but nothing is 100% efficient. Your motor is probably more like 1/2 to 2/3 HP. Could even be less, these machinery companies are known for exorbitant exaggeration.
> Looks like a potentiometer and terminals are included. You'll have to purchase the HP resistor separately. Pick a HP resistor somewhere between
> 1/3 and 3/4 HP and you should be fine. There is some latitude there. Expect to touch up the adjustments for torque compensation and start-up speed when you get the unit running.
> -M



Mark, you’re a legend, can’t thank you enough. I’m confident I know what I need to, to get this machine running now. Hopefully the board will be here around Wednesday. I’ll update the thread once the board is on. Don’t know what I’d of done without the help on here.


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## markba633csi (Jun 12, 2020)

Great news,  glad to help.  
-M


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## ProfessorBean (Jun 12, 2020)

markba633csi said:


> Great news, glad to help.
> -M



Hi Mark, sorry to be a pain but I just wanted to run something by you. I have found a local supplier for the horsepower resistor. From the advice you have given, I believe I need part number: 9836 which is for 1/3-1/2hp at 200v.

I intend to buy resistors on either side of that one, so that I can choose the optimum one.

My question is, what would be the symptoms of an incorrect resistor? 




			https://acim.nidec.com/drives/kbelectronics/-/media/kbelectronics/documents/dc-drives/data-sheets/plug-in-hp-resistor-and-fuse-selection-chart.ashx?la=es-es
		



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## markba633csi (Jun 12, 2020)

I think the 9836 sounds like a good fit.  The symptoms of an incorrect one would be that the torque compensation would not work properly; motor speed would change under varying loads.  The adjustment pot on the board may be at the end of it's range.  You want it to be sort of in the middle, optimally.  The speed control would still work, but the controller should be able to hold the speed pretty constant under load if the feedback is working properly.
I looked online to try to pin down the exact HP rating of the DC brushed Seig C6 but I only found references to the fixed speed single phase AC motor (0.75HP) and the brushless version.  Best I can figure is somewhere between 1/3 and 3/4 HP
I'm fairly certain you only need one resistor size.  There is some latitude, like I mentioned earlier.  Try the 9836 first.


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## ProfessorBean (Jun 12, 2020)

markba633csi said:


> I think the 9836 sounds like a good fit. The symptoms of an incorrect one would be that the torque compensation would not work properly; motor speed would change under varying loads. The adjustment pot on the board may be at the end of it's range. You want it to be sort of in the middle, optimally. The speed control would still work, but the controller should be able to hold the speed pretty constant under load if the feedback is working properly.
> I looked online to try to pin down the exact HP rating of the DC brushed Seig C6 but I only found references to the fixed speed single phase AC motor (0.75HP) and the brushless version. Best I can figure is somewhere between 1/3 and 3/4 HP



Many thanks once again. All makes perfect sense now. The cost of the resistors is just £4.50 and the supplier is only 30 mins away from me so it’s not a problem for me if I need to change it for any reason 


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## markba633csi (Jun 12, 2020)

I've been using a KBIC-125 for a few years now with a surplus servo motor of unknown horsepower, with great results.  Not affiliated with KB, just a satisfied user


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## ProfessorBean (Jun 13, 2020)

markba633csi said:


> I've been using a KBIC-125 for a few years now with a surplus servo motor of unknown horsepower, with great results. Not affiliated with KB, just a satisfied user



Good to hear. I’d never heard of them until this thread, but then again I’ve never had to do anything like this before. This is the first but I can guarantee not the last time I use KB. My father wants to motorise his honey spinner at some point so I think they may be good for that. I believe the boards are made in America too which is always nice.


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## markba633csi (Jun 13, 2020)

Your dad have hives? I've always wanted to get into bees


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## ProfessorBean (Jun 13, 2020)

Yeah he has around 11 hives so quite a lot of honey this time of year. I’ve had 2 hives for the last 4 years but gave it up this year as I’m concentrating on other things.

It is very rewarding and you can put in as much time as you want. My dad is in his hives every few days. 

The minimum requirement at this time of year is that you have a look in the hives at least every 7 days, to see if the bees are getting ready to swarm. The other thing to check is if they are running out of storage space and to keep an eye out for any medical issues. Varroa mite is one of the biggest problems. They look after themselves other than that. 


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## Buffalo21 (Jun 13, 2020)

markba633csi said:


> 746 watts/ HP at 100% efficiency, but nothing is 100% efficient.  Your motor is probably more like 1/2 to 2/3 HP.  Could even be less, these machinery companies are known for exorbitant exaggeration.
> -M




Mark,

We gauge everything on a Clydesdale horse, they gauge them on a little Asian horses................the horsepowers are not equal.........


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## hman (Jun 13, 2020)

Amen!


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## ProfessorBean (Jun 22, 2020)

Hi guys, just an update if you are interested. 
I installed the board and initially had a problem with the resistor being for a lesser horse power (the chart I linked on here was a different chart that came with the board). I swapped it and it is now running like a dream.

Thanks for all the help 


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