Clarke CL300

[SteambuffParticipant @steambuff]

 

ArcEuro have the ones for the Sieg … (or they did when I got my spare one last month

 

Dave

 

[john swift 1Participant @johnswift1]

HI Neil

you can’t beat a free sample !

 

a quick search for a 4k7 potentiometers plus double throw switch this morning

 

directed me to this link – http://www.omeg.co.uk/index.htm

 

 

while all the retailers of the machines using the original part

normally have them in stock

 

for a club for instance , spares from Omeg look like an economic alternative

if its made from stocked parts

£25 for 10 + carriage + vat       (about the cost of 3 or 4  original parts ?)

 

John

 

Edited By john swift 1 on 08/10/2011 20:37:37

[philip catonParticipant @philipcaton13198]

Hi john

I have been reading all of your posts because I have a fc250j/230v board of the smd type in my clarke lathe which after some use started to speed up and then go back to normal untill the next day when I switched on it was at full speed. Ho I thought I have seen posts by John Swift about the IRFP250 going sc so ordered and found that with replacement no differance. So checked the speed pot 4.7k lin seemed ok and 12v supply seems to be right and adjusting, also checked c2 and the diode on the motor supply all seems OK. I got a 4.7k lin pot from Maplins and took the switch apart and you can change the contacts inside so that it is in the on position when off, and turning on the switch it goes oc but alas it works just as the original. So I am still trying to find out why I cannot control the speed any thoughts???

Phil

[Kiaran WalkerParticipant @kiaranwalker64939]

Hi Phil

 

Does re-wiring the switch give you the no voltage protection and is it easy to do?

 

Kiaran

[philip catonParticipant @philipcaton13198]

Hi Kiaran

Yes the switch after doing the mod works as the original the part no on my recipt from Maplins is FW41 sw Pot lin 4k7 to do the mod you have to remove the switch part by bending back 4 metal lugs very easy to do. When removed there are 2 copper rivets in the diaginal corners you have to drill these out the the switch will come apart the lower part has the contacts in you can remove these and put them in the vacant spaces behind reassemble and I super glued it back together using ordinary super glue with the addition of super glue accelerator a must I think for any model engineer. The make I use is by Pacer part number 09531 can be found on Ebay 2fl oz about £5. Hope this helps

 

Phil

[john swift 1Participant @johnswift1]

Hi Phil

 

first , replace the motor with a 60 to 100w GLS bulb (not an eco bulb)

this will save the motor and board from damage

 

few easy tests

 

without the potentiometer connect P2 and P3 this should give you zero speed / output ?

 

check the voltage across D6 and D7 is 12V

(they are near the IC nearest to the green connector)

 

disconnect R8 (= 68K , its in the middle of the large resistors)

does this turn off the FET’s and make the output zero ?

 

I try to find picture of the board to show test points for the IC’s later

 

John

 

PS  once I’ve traced the circuit details for the SMD version of board

       I’ll look in to testing the control circuit with an external DC supply

      to limit the need to work on the board while live !

 

 

Edited By john swift 1 on 09/10/2011 19:31:01

[philip catonParticipant @philipcaton13198]

Hi John

 

Just completed test D6 & D7 have 12V across them with link in P2&P3 blub glows dimley with R 8 disconected there is no output bulb not lit.

I have had the bulb connected for all test as I have the seed box on my test bench.

 

Phil

[john swift 1Participant @johnswift1]

Hi Phil

 

that works as expected

 

If you re connect R8

 

and link P1 and P2 that should give you about half power (full speed in reverse)

 

linking P1 , P2 and P4 will give you full power , the bulb full brightness

 

if that works try with the potentiometer you should have control of the test lamp

 

John

 

 

 

 

 

 

 

 

[philip catonParticipant @philipcaton13198]

Hi John

 

Just did the test after connecting R8 up and on linking P1 & P2 it gives full power and there is no differance when P1,P2 & P3 are connected

 

Phil

[john swift 1Participant @johnswift1]

 

Hi phil

 

looking at the diagrams for the ealy version of the speed control

 

if the 220K 1W resistor (R3) is open circuit you will see no change of voltage at point “A”

so you will have no negative feedback through U1a and U1d to the virtual earth point

at the junction of R29,R30, R31 ,R33 and the inverting input of U1c ( pin 9 )

 

R3 is near the heatsink and preset resistors

 

that could be why linking P3 and P2 gives a very small output voltage

 

but the potentiometer at its minimum you have full output

(a small positive voltage not zero as when P3 and P2 are linked )

 

most but ,not all components are labled the same on both versions of boards

John

 

 

[philip catonParticipant @philipcaton13198]

Hi John

 

You have do it again yes it was the 220 k that had gone OC all seems to work OK on the lamp I will fit the speed box on the lathe tonignt, many thanks for your thoughts on this problem and lets hope it will help others.

 

Phil

[john swift 1Participant @johnswift1]

Hi Phil

 

a good result

 

I’m glad it was an easy part to replace and not one of the dozen or so surface mount

devices next on the list to check

 

John

[Kiaran WalkerParticipant @kiaranwalker64939]

Posted by philip caton on 09/10/2011 18:13:35:

Hi Kiaran

Yes the switch after doing the mod works as the original the part no on my recipt from Maplins is FW41 sw Pot lin 4k7 to do the mod you have to remove the switch part by bending back 4 metal lugs very easy to do. When removed there are 2 copper rivets in the diaginal corners you have to drill these out the the switch will come apart the lower part has the contacts in you can remove these and put them in the vacant spaces behind reassemble and I super glued it back together using ordinary super glue with the addition of super glue accelerator a must I think for any model engineer. The make I use is by Pacer part number 09531 can be found on Ebay 2fl oz about £5. Hope this helps

 

Phil

Hi Phil

 

Not working for me, the switch now cuts the power when switched on as I thought it might as it just seems to be reversed, like off when on.

 

Kiaran

[philip catonParticipant @philipcaton13198]

Hi Kiaran

 

Sorry to here you have not been able to get it to work I have mine in my Lathe and it works OK, just wondering is the switch part white in colour ? my one had on the terminal ends a round inpression and the stamping 4/80 over 250 then below d CCA and the make OMEG as the switch is double pole both are working but you only use one of the poles.

 

Phil

[Kiaran WalkerParticipant @kiaranwalker64939]

Hi Phil

 

Exactly the same , using one pole I have cable 5 on one terminal and cable 3 and another one leading to the emi filter on the other, pardon my ignorance but if the switch is off in the on position how does the power get through?

 

Kiaran

Edited By Kiaran Walker on 10/10/2011 19:18:21

[john swift 1Participant @johnswift1]

 

Hi Kiaran ,

 

with the switch closed and a direction selected

the relays normally open contacts close

 

one connects the positive supply to the motor

and the other is in parallel with the switch on the speed control ( terminals 6 & 7)

 

this maintains the circuit when the switch opens as you turn the speed up

 

the resistors R43 and diode D6 enable two in expensive 24V dc relays

to be used instead of a more expensive two pole main operated relay

 

John

 

 

PS points BR are the DC supply to the controle circuit

 

 

 

                                             

Edited By john swift 1 on 10/10/2011 20:03:01

[Kiaran WalkerParticipant @kiaranwalker64939]

John.

 

Not much good with these types of diagrams but from what I can tell I can hear what must be the relays engaging when the power is turned on but when the pot switch is turned to on, or open contacts, the relays can be heard opening, hence no power.

 

Kiaran

[john swift 1Participant @johnswift1]

Hi Kiaran

 

it looks like one relay is faulty or the printed circuit is open circuit

 

see if you can check the connection form terminals 3 and 5 to the relay

in the diagram below

 

the track ( in red) from AC3 to the relay is hidden

you should be able to see terminals 5 and 7 to the relay common

 

 

John

 

 

Edited By john swift 1 on 10/10/2011 22:34:00

[Kiaran WalkerParticipant @kiaranwalker64939]

John,

 

Connection from 3 and 5 to each test point is ok, one having a very slightly higher value, also got the same reading between 3 and 5 and the left RLY in the top pic. but nothing between 3 and 5 and the relay common.

 

Kiaran

[john swift 1Participant @johnswift1]

Hi Kiaran

 

I have managed to get a picture of the board that shows how to test the relay

 

John

 

[Kiaran WalkerParticipant @kiaranwalker64939]

oops, thanks john,

 

now I see a bit clearer, I can energise the relay and get a connection between the two 3’s on the yellow line, 3 + 5 show a connection with the relay energised or not, this is with the pot. switch off or closed contacts.

 

Kiaran

[john swift 1Participant @johnswift1]

Hi Kiaran ,

 

 

start with the board as in the second picture , you can connect your multimeter

across terminals 3 and 5 , to test for continuity

(I fitted the probes under the wire clamps)

 

with an external DC supply , as shown across the relay coil ,( two PP3’s will do)

the relay should connect terminals 3 and 5 together

 

if this works ,when the board is reinstalled

the relay contacts are connected in parallel with the switch on the back of the poentiometer

 

when the relay is working correctly , it maintains the power when you move the control clockwise and away from the anticlockwise end stop

the switch is now open but the relay connects terminals 3 and 5

 

think of the speed control switch being like the green start button on a

direct on line starter, its closed just to start the motor

 

John

 

PS    the yellow line just shows the hidden printed circuit connection between

         terminal 3 and the tag on the relay

 

 

 

Edited By john swift 1 on 11/10/2011 16:57:15

[Kiaran WalkerParticipant @kiaranwalker64939]

John,

 

Just had another try with similar results using a laptop charger at 20v. there is plenty of clicking going on but no activity between 3+5, looks like a break somwhere.

 

Kiaran.

[john swift 1Participant @johnswift1]

Hi Kiaran ,

 

the relay is Omron G5LA-1 24V

 

maplin don’t stock the relay , but

 

Farnell have it part number 1455505

 

RS Component are out of stock part number 683-9141

 

so you have 4 options

 

1, replace the board – quick but expensive option

 

2, replace the relay

 

3, use an alternative No Volt Release switch

 

4, use the Maplin potentiometer and loose the NVR function !

 

 

John

[Kiaran WalkerParticipant @kiaranwalker64939]

John,

 

I think for now I will do without the NVR function and pick up a couple of relays for my to-do list, they’re so cheap. Should be ok now, it’s all sinking in slowly but surely.

 

Thanks ever so much for guidance and info. on this matter, really, you is a star matey!.

 

Kiaran.

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