speed control pcb for Clarke CL300 lathe

[john swift 1Participant @johnswift1]

Hi Jon ,

 

the original panel fuse holder was fitted with a 20mm 2A quick blow fuse

 

have a look at maplin

 

fuse holder DA59 P

 

20mm 2A fuse GG26D

 

ensure the live supply goes to the rear terminal of the fuse holder

 

the terminal on the side of the fuse holder goes to the front of the fuseholder

and it is possible when removing a good fuse to make contact with it

 

John

 

[William SmilesParticipant @williamsmiles10916]

Hi John,

 

Thanks for the post, will see if I can get hold of some brass and make some. Thanks for the photo and information, will let you know how I got on.

 

Best wishes,

 

Bill.

[flintlockand steelParticipant @flintlockandsteel]

>quote

………… on my board I replaced a link with a 1N 4148 diode and 12K,resistor

and added a 47uF acpacitor , to make it like the later versions …………….

<

………………. Is there any other element to the resistor and cap’ spec?

Such as Tant cap or resistor ratings, tolerences, wire wound etc?

[flintlockand steelParticipant @flintlockandsteel]

Hi John

I forgot to ask. P1-3 are these the little pre-set pots on the board?

[john swift 1Participant @johnswift1]

Hi Jon ,

 

P1 to P3 are te connections to the speed control

( in the corner between the heatsink an the small pcb with IC’s on it )

 

if you follow the copper print from terminal P2 ( this is the middle terminal from the speed control potentiometer)

the link to replace looks like a resistor with one black band and connects to teminal VG

on the small pcb.

the control voltage at this point is only 12V at full speed

 

 

the resistor I used was a 0.6W metal film resistor from maplin code M12K

but any small 12K 5% resistor that will fit will do

 

the capacitor is a 47uF 16v electrolytic (usually 20% tolerance) eg maplin AU01B or VH32K

the negative end goes to the cathode of zenner diode D7 (and P3 , link RX )

 

the cathode of 1N4148 connects to P2

 

as you increase the speed the capacitor slowly charges via the 12K resistor

but when you reduce the speed the capacitor quickly discharges via the diode

to P2.

 

note depending on the wires on the diode and resistor

you may find it difficult to feed both wires through the board

 

John

 

ps the presets are R12 , R15 and R37

[flintlockand steelParticipant @flintlockandsteel]

Hi John

Just to say thanks for all the info. After spending some time searching suppliers I went with Farnell as they don’t lock you in to large pack quantities. Also orders over £20 from UK stock are free shipping (min card order is £20). As it is it’s cheaper for me to drive to Leeds than order on line. Other suppliers were almost double the cost for the bits with their shipping charges.

I may still need the odd pointer but hopefully all’ssorted and I’ll have a working lathe by the weekend.

Jon

 

[flintlockand steelParticipant @flintlockandsteel]

Hello John

I can see 3 resistor-like links (one of which is hiding under the middle pre-set pot in this pic. Just to confirm, is it the one next to the black cap’ (RX) , it goes to P1&3 (top side track), that I swap?
P2 looks as if it goes to R0 link.

Actually, is link R0 removed or just tied in?

Hopefully finally is it the black end of the diode goes to the P1&3 end?

Many thanks

Jon

[john swift 1Participant @johnswift1]

Hi Jon ,

 

the link is the middle link ,( one of two marked ” R0 ” ) 

hidden by the middle preset ( R12 the sealed current limit preset) in your picture

 

hope the pictues help

 

 

John

 

PS did you check the FET’s after you had removed them ?

 

Edited By john swift 1 on 09/02/2011 19:41:45

Edited By john swift 1 on 09/02/2011 19:45:32

[flintlockand steelParticipant @flintlockandsteel]

Hi John

Yes 1 FET is totally gone, and the other is doubtful.

If I’m reading this correctly the diode & resistor combo replace the link while the cap bridges to D7.

What are the turquoise lines?

 

Jon

[john swift 1Participant @johnswift1]

Hi Jon ,

it might be worth checking the opto isolators have survived

 

if a fet was short circuit drain to gate

the transistor in the opto isolators can be damaged and the 100 ohm resistor connected to the gate

it looks like the 18V zenner and R9 (1k8) has been replaced

the isolators are switched alternately on and off

the gate voltage switches between 0V ( same as the FET source terminal) and +18v ,

 

     John

 

PS   just incase

   it may be worth testing the repaired with a 100W  GLS bulb in series with the mains supply

and a 15W or 25 W pigmy bulb as a dummy load , as in an earlier post

 

 and checking the motor

 

 PPS   the line just shows the  common 0V connection between the two 12V zenners

 

           D7 ‘s cathode where I connected the negative capacitor terminal

           and D6’s anode

           this junction is connected to P3 , the minimum speed end of the

           speed control potentiometer

 

           the short line from VG and the positive end of the capacitor is the

          printed circuit connection on the under side of the pcb

Edited By john swift 1 on 09/02/2011 21:07:03

Edited By john swift 1 on 09/02/2011 21:12:35

Edited By john swift 1 on 09/02/2011 21:20:46

Edited By john swift 1 on 09/02/2011 21:24:58

Edited By john swift 1 on 09/02/2011 21:38:02

[flintlockand steelParticipant @flintlockandsteel]

Ooops didn’t see the last post there. I sorted out the FETs but thought to give it a quick test at that stage.

Not happy. Now, as soon as mains power is switched on (while the speed control is off) the chuck twitches then the fuse blows, where as previously it was running flat out.

Really think I need to get this board off for a thorough checking as it’s a trip to Leeds every time and in time and money, that’s prohibitive.

Any recomendations as to where to send it?

I guess a replacement board is horribly expensive.

 

Jon

[john swift 1Participant @johnswift1]

Hi Jon ,

 

the first thing I’d do is test the board without the motor

don’t forget all the board is live

 

first with a 100W (or 60W) gls bulb in series with the live supply

this acts as a current limiter if D1 (FR307) , C1 (4n7F 2000V ) or the bridge rectifier( KBPC1010 ) are short circuit – eco compact flourescent bulbs don’t work for this test

and a 15W bulb in place of the motor.

 

if the board is working you should be able to control the brightness of

the 15W bulb / dummy load

note the 15W bulb may just glow at the minimum speed setting

 

next if that worked connect the mains as normal and test with the 100W bulb

as the load.

passing this test points to the motor (or too small a fuse)

 

if you have no control and the 15W bulb is at full brightness

 

check C2 ( 4n7 600V) , D2 ( FR109) and the FET’s are not short circuit

 

for testing with the bulbs you can first remove C2 , ( removes C2,D2 and R42

from the circuit)

next lifting one end of R9 (1k8) will remove any voltage switching on the fets if

the opto isolators or the PWM control is faulty.

may save removing the FET’s if they are OK

 

Arc euro trade are selling the new SMT boards for £60 if you need a quick fix

once the motor is tested

 

John

 

 

[flintlockand steelParticipant @flintlockandsteel]

Hi John

You’ve been so helpful, I hate to give up on this, but time etc is against any further repairs. The motor was fine before so I’m assuming it still is and the problem is in the board.

Any idea what the part number is with Arc? I tried typing in SMT and drew a blanc.

 

Jon

 

 

[john swift 1Participant @johnswift1]

Hi Jon ,

 

The new boards use surface mount components that are more difficult to replace.

so i’d keep your old board as it could be a spare when you have time .

 

I’ve have , but the only person I know that repair boards as a business , doesn’t repair boards with surface mount components.

 

see http://www.repaircontrol.com

 

replacement pcb :– Arc Euro Trade part number C2-FC250J-PCB

 

http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/C2-Mini-Lathe-Spares

 

 

John

[flintlockand steelParticipant @flintlockandsteel]

Thanks for the links there John

Arc are listing it as out of stock. I’d really like to have this up and running as soon as possible. There must be another UK supplier but if I type in C2-FC250J I only get this forum or Arc.

Yes I looked at the US site but given the potential costs I think it will be quicker and probably cheaper to buy new in the UK.

Jon

[john swift 1Participant @johnswift1]

Hi Jon ,

 

C2-FC250J is the Arc euro trade part number a combination of the

lathe and pcb number

 

the actual number Sieg part number is FC250J/230V

 

Machinemart usually have it instock but is likely to be £80 or £90

 

note —- the latest boards used in the CL300M is XMT2325

the manual with the revised wiring can be dovnloaded from this page :–

http://www.machinemart.co.uk/download/cl300m.pdf

 

the XMT2325 controller has an additional over current protection circuit

 

other possible UK suppliers are Warco and Chester machine tools

but I’ve not ordered from them.

 

John

[Mira ProrokParticipant @miraprorok23228]

Hi all,

at first excuse my and google´s English. Maybe it is already discussed here, but maybe I did poorly understood. I have older FC250/230V with FETs on the left. My broblem: first it was not completely stop the engine. The engine is still spinning slowly. I set the trimmers to the daughter board and all was ok. But only for a two days. Then the same problem. Setting trimmer has had no effect. There’s so much that it now has no response to rotation of the potentiometer knob. I allready replace the both FET transistors, Til 113 and LM324N. But nothing. It seems to me that a daughter board is not working as it should. Voltage on the optocouplers does not change when I turn potentiometer. Would help me if I knew what the approximate voltage should be on U1c pin 8,9 and U2a pin 2,1 at potentiometr set min. and max position. Or any other ideas how to revive the regulator? Can anybody help me? Than you very much for any reply.

 

Mira

[Richard ParsonsParticipant @richardparsons61721]

Some 36 years ago I bought a reconditioned single phase motor. 4 years ago I had it re furbished at the cost of about £6 (2,000 Hungarian Forints) which included a new set of bearings. There was a tendency for it to have a problem with its starting windings. I am now on its second belt (about 16 years old).

It gives me all the speeds I need for my old Myford. What price electronics?

 

Regards

Dick

[Les Jones 1Participant @lesjones1]

Hi Mira,

Measuring the voltage on the optical couplers with a digital meter may not give meaningful results as it is not a smooth voltage change. It will be a square wave with varying duty cycle. You should see a change using an analogue meter as it will read the average voltage. As adjusting a trimmer seemed to fix the problem for a couple of days I suspect a capacitor or resistor changing in value as semiconductors usually fail suddenly. Electrolytic capacitors are the most likely component to fail. If you have access to an ESR meter (Effective series resistance.) then checking the capacitors with this would be a good place to start. Since I built an ESR meter I have found it a very quick way to find faulty electrolytic capacitors.

 

Les.

[Mira ProrokParticipant @miraprorok23228]

Hi Les,

thanks for your answer.

Today I pull out all capacitors and tested them for ESR and capacity. All are ok. But nothing changed. Very interesting is, when i switch reverse then regulator controls but not to zero. When I switch normal, regulator does not regulate but is open to the max. I dont know how it is possible. Tested with classic 100W bulb. It looked like a fairly simple circuit without memories, processors, SMD ……. and such problems.

 

 

 

@ Dick

 

Excuse me, but I’m afraid that I completely misunderstood the meaning of some parts of what you wrote. In Czech I can´t buy this regulator, it is possible to buy it in england, but it´s more difficult.

[Les Jones 1Participant @lesjones1]

Hi Mira,

Looking at the schematic it looks like contact on the reversing switch connected to P4 causes the motor to run at about half the maximum speed when in reverse. I suspect the trimmer P15 may be faulty. With no power to the board check the resistance between the slider of P15 and the end connected to -12V and make sure that as the trimmer is adjusted the resistance goes between zero ohms and about 30 – 50 k. Also check that the +12 V and -12V supplies are correct. (+/- 10%)

Richard Parsons comments refer to a fault he had on an AC induction motor. It is not relevant to your problem.

 

Les.

[Liam ThorntonParticipant @liamthornton83008]

Hi!

 

Newbie to the site hoping for help. I’m guessing the answer to my question is already posted here but I’m baffling myself reading all the threads….

So here goes:-

 

My Clarke CL300 has been working fine until last week when as soon as you select forward or reverse with the emergency button out it runs at full speed with the potentiometer clicked off. As soon as you turn the potentiometer the motor stops. Click the potentiometer to the off position and away it goes.

 

So I ordered the mosfets from RS and soldered them on and re-fitted every thing. The sucsess was short lived. For the first operation all worked as it should. I let the motor stop and tried it in reverse. This time the motor ran erratically and then settled to normal operation. I then put the piece I had been turning back in the machine and clicked the forward button – Oh , full speed or nothing, exactly as before.

 

Took the board out again and checked the resistance on the mosfets – not good. What do you think has caused this?

 

Thanks in advance

 

Liam

[Liam ThorntonParticipant @liamthornton83008]

Forgot to say – The speed control board is labled FC250JSMD If this helps

[Pat BraveryParticipant @patbravery]

Hi Liam, The forward/reverse switch can be a problem, I had to change mine after similar problems, they are fairly cheap from Clarke and as the problem happened just after using this switch was used it may be worthwhile checking. It should be smooth and positive in action. Good luck and keep us posted, regards Pat

[Liam ThorntonParticipant @liamthornton83008]

Hi Pat!

 

Thanks for that, I’ll check it out but I think the problem is the Diode thats up by the Mosfets. I’m sure I tested it before and it was OK but now it’s not a Diode

 

 

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