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Member postings for Les Jones 1

Here is a list of all the postings Les Jones 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: Coping with voltage spikes
13/08/2020 20:04:52

Tim, You are going to have to provide more information on the "LED". A single actual LED (I am assuming it is a white LED as different coloured LEDs have different forward voltages.) would have a voltage of between 3.0 and 3.6 volts across it when driven with it's rated current. As you are calling it a 12 volt LED it must contain something to limit the current and it may consist of more than one actual LED. Until we know more about the "LED" we can't work out a possible reason for it failing.


Thread: Death of a PSU
25/07/2020 11:52:20

The TNY264 is also a 7 pin low power switch mode regulator chip. It would be nice to know the part number of the chip on the board as the picture is not good enough to read it.


Thread: Son`s mini lathe Clarke CL300
17/07/2020 09:23:14

This is a link to the manual for the CL300M which contains a wiring diagram but not a schematic of the board. (Which I have not been able to find.)


16/07/2020 20:24:32

Am I correct that when you say " mixed up he has said they were the ones going to the emergency stop button the on and off." that you mean that he connected the output of the on/off switch to terminals K3 and K4 and that he connected the wires from the emergency stop switch to terminals L1 and L2. If so I don't see that this would cause the varistor to fail but it almost certainly would have damaged other components as he connected the mains to the low voltage part of the board. The varistor is probably connected directly across the mains input to the board (terminals L1 and L2) so I think this just failed or failed due to a high voltage transient on the mains.


15/07/2020 22:17:50

Telling us which wires you connected to the wrong place may help to identify what damage you have done. Tell us the correct places the wires should connect to and where you actually connected them. can you also post a picture of the under side of the board near the burned area.


Thread: Voltage feeding DRO "usb" digital scales?
02/07/2020 09:01:56

Hi Robin,
I started using Chinese scales with the Shumatech DRO350 many years ago. There was a lot of discussion on the Shumatech forum about jitter on the displayed values when the scales were supplied from the DRO 350 rather than their internal button cell. A few of us traced this to the fact that there was a section of PCB track between the 1.5 volt regulator and the negative connection to the scales that also carried the negative supply to the multiplexed LED display. The multiplexing current caused a small amount of voltage ripple along this section of track which was enough to cause the readings from the scale to jitter. This showed that the scale reading was effected by variations in the 1.5 volt supply. So I think adding the regulator reduced the sensitivity to battery voltage variations. Also using the CR2032 increased the battery life.


01/07/2020 20:28:00

Hi Robin,
I have some digital calipers that use CR2032 cells but the data output is still 1.5 volts. I think they have a built in regulator to drop the 3 volts down to 1.5 volts.


01/07/2020 09:09:39

I have always supplied this type of scale with 1.5 volts when using home made remote displays. I think you will find the remote power connections connect directly to the internal battery contacts. The recommended silver oxide cells are rated at 1.55 volts when new. I have used an LM317L to provide the 1.5 volts supply from the 5 volt rail for the logic in my remote displays. Although USB connectors are used on these scales they DO NOT use USB protocol.


Edited By Les Jones 1 on 01/07/2020 09:10:19

Edited By Les Jones 1 on 01/07/2020 09:25:05

Thread: 3 Phase in a Model Engineers workshop
18/06/2020 16:48:20

Hi Tony,
Good look with finding someone local that can help you. I'm Sure we would all be interested in knowing the the solution to the problem. (And giving any more assistance if required.)


17/06/2020 14:35:18

Hi Phil,
At first I had doubts about it being a ROTARY converter as I could net see the motor part of the converter. At sight it looked like the converter box was right against the wall. On the Transwave website the motors all seem to be mounted on the back of the box. I had a closer look at the picture and I think I can just see the fan end of the motor behind the output socket. I can't understand how the contactor can pull in when fed via the start button but not by the maintainer contact. The only thing I can think of that may be happening is the contactor is chattering in and out while the start button is pressed. When it pulls in and the load is put on the phase that is supplying the coil the coil then drops out. As soon as this happens the load on the phase that is supplying the coil is removed so it pulls in again. If this is happening then it would not hold in when the start button is released. Monitoring the coil voltage (Or listening for noise from the contactor.) would prove or disprove the theory. (I am assuming that there is no fault in the internal machine wiring as we where told is was working in the previous location.)


17/06/2020 09:44:36

One important question asked by Andrew Johnston on 14/6/20 at 09:31 has not yet been answered, I was thinking of doing a simple test using 6 old fashioned mains filament lamps of 60 to 100 watts rating. (All the same rating) The idea is to have three series connected pairs of lamps with each pair connected across the three phases on the motor. (Making the connection at the output side of the thermal trip that feeds the spindle motor is probably the easiest.) The brightness of the lamps would give a reasonable idea of phase balance.(50 watt GU10 bulbs could also be used as they are easier to obtain. ) Another test that could be done is to disconnect the spindle motor at the output of the thermal trip and see if the contactor stays in and the coolant pump motor runs. I am inclined to agree that someone is required on site who is used to working on three phase motors and tracing exactly how the contactor maintainer contact and interlocks are wired.


14/06/2020 09:19:45

Hi David,
I think you should start your own thread relating to your problem. It can get very confusing discussing a number of different problems in the same thread.

Hi Tony,
I think an extra picture of the isolator door with the camera moved to the left a bit or the door swung about 30 degrees more closed might help. In the original picture I can't decide if the terminals on what I think is the contactor are in the horizontal or vertical plane. ( I think from the fact that it looks like the contactor coil is at the bottom of the picture that the contacts are in the horizontal plane.) It might also help identify the two things either side of what I think is the contactor. ( My best guess on these is thermal overload cut outs, one for the main motor and one for the coolant pump.) I think the right hand set of the four contacts on the contactor is the maintainer set to hold the coil in when the start button is released. I will avoid making any more comments at the moment as Phil seems to be thinking along the right lines and recommending sensible actions to diagnose the problem.


Edited By Les Jones 1 on 14/06/2020 09:21:39

12/06/2020 20:22:28

It sounds like the contactor is not holding in. Is the start button just a push button switch or is it the type were the button actually pushes the contactor closed ? (It is probably just a push button as I have only seen the type were the start button pushes the contactor closed on hobby machines.) The start button is normally wired in parallel with an auxiliary contact on the main contactor. WITH THE MACHINE ISOLATED FROM THE POWER connect your multimeter set to a low ohms range to the two connections on the start button (You will probably get a reading of a few tens or hundreds of ohms at there will be a path through other circuits.) Now manually push in the main contactor. The resistance reading should drop to almost zero ohms.If you can post the internal wiring diagram of the machine that would be a great help to suggest other possible causes of the problem. I first thought the problem might be inbalance between phases but the fact that the contactor pulls in while the start switch is held in disproves this theory.


Thread: component tester
08/06/2020 08:47:29

I think you need to give more details than just "A component tester" For example model number, manufacturer, the magazine article you built it from. I think it is expecting a lot for it to be recognised from just a picture of the display.


Edited By Les Jones 1 on 08/06/2020 08:47:59

Thread: Lathe motor
28/05/2020 09:02:07

A series wound motor is a bad choice for driving a lathe as it's speed varies a lot with load. They can be reversed (Both when supplied with AC or DC.) but you need to change the internal wiring of the motor to reverse the relationship of the current through the armature and the field winding. If you supply some details of the motor that is fitted that may be a better option than the Kenwood motor.


Thread: Clark CL430 question on threads
24/05/2020 18:09:44

If it gives a change wheel setup for any thread you should be able to work out the leadscrew pitch. If you can't work it out post the information here ant there will be may members that can work out the leadscrew pitch.


Thread: Oscilloscope kits - any recommendations?
10/05/2020 14:24:03

7 BCD Scales
LSB Sent first.

Static state of clock line between frames Low
Time between start of frames 330 mS
Length of data frame 820 uS
Interrecord gap 329 mS
Time between stat of nibbles within frame 110 uS
Length of clock cycle about 12 uS
Time clock pulse is negative about 6 uS
Time clock pulse is positive about 6 uS
High level at start of frame about 55 uS
High level between nibbles about 60 uS
High level at end of frame about 60 uS

Clock in the data on the negative going edge.

Top nibble
Bit 0: sign. L = +, H = -
Bit 1: in inch-mode H means +0,0005 inch, unused in mm-mode.
Bit 2: unit: mm/inch. H= mm; L= inch
Bit 3: unknown.

28 bits in a frame of data

CPI 2540 (Metric)
iGaging (21 bit)

LSB sent first
The 21 bits are all used as a 21 bit binary number. (No bits used as flags.)

Static state of clock line between frames Low
Static state of data line between frames
Time between start of frames 7 mS
Length of data frame about 2.33 ms
Interrecord gap about 4.67 mS
Time between clock pulses about 111 us (Clock cycle time.)
Time clock pulse is negative about 89 uS
Time clock pulse is positive about 22 uS
High level at start of frame about uS

Clock in the data on the negative going edge.

CPI 2560

21 bits in a frame of data

I collected this information when I was writing code to read all the above types using an Atmel Attiny4314.


10/05/2020 14:21:22

Hi Robin,
This information on scale protocols may help you.

Scale protocol information.

2 * 24 bit scales

Data is sent as two groups of 24 bits.
Each group is a 24 bit binary number. The first bit received is the least significant bit.

are transferred LSB first! Also, data is 2's complement. (ie inverted Data signal at 0 volts = 1 at +1.5 volts = 0)

Static state of clock signal between frames Low
Time between start of frames 330 mS Normal mode 25 mS fast mode
Length of data frame 860 uS
Length of clock cycle about 14 uS
Time clock pulse is negative about 7 uS
Time clock pulse is positive about 7 uS
Initial high at start of frame about 52 uS
High in the middle of frame about 110 uS
High at end of frame about 80 uS

Clock in the data on the negative going edge.

The first group is the absolute position. It has some arbitary value at power on.
The second group is the relative position. This will be zero after the zero button is pressed.
Its value will be the difference between the absolute value when the zero button was pressed and
and the current absolute value.

48 bits in a frame of data

CPI 20480


HF (Bin 6 scales)
LSB Sent first.

Static state of clock line between frames High
Time between start of frames 180 mS (I measured about 210 mS)
(I have seen 133 mS quoted elsewhare.)
Time of gap between nibbles about 700 uS
Length of data frame 13 mS
Interrecord gap 167 mS
Time between start of nibbles within frame 2.2 mS
Clock cycle time about 450 uS
Time clock pulse is negative about 320 us (Logic 1)
Time clock pulse is positive about 130 us (Logic 0)

Clock in the data on the positive going edge.

The data output is the number displayed on the LCD display.
Set scales to metric mode and this will corespond to 2540 CPI ( 0.01 mm) per count)

24 bits of data (6 bytes) Least significant comes out first. Bits 0 to 19 is the reading in binary (The same value as that displayed in decimal on the scale display. Bit 20 is the sign bit set for negative Bits 0 to 19 are always a positive number.
Bit 23 is set when in inch mode.

24 bits in a frame of data

CPI 2540 (Metric) (2000 in imperial mode.)

This is only half of it as it would not let me include it all in 1 post. The rest is in my next post.


Thread: Motor Reverse
06/05/2020 19:54:16

Assuming that the black cable is the only other cable going to the motor as well as the blue cable to the capacitor then if the black cable is two conductors plus earth then the motor can't be reversed externally. If it is four conductors plus earth then it probably can be reversed externally. If you are prepared to take the motor apart then it may be possible to reverse it. This may involve digging into the end of the winding to get at the point where one end of the start winding is connected to one end of the run winding and to an external wire. the connection between these winding ends would have to be separated and brought out as two separate wires.


Thread: Cutting down a linear glass DRO encoder
05/05/2020 12:35:53

Hi Robin,
Thanks for the reply. I am now wondering if the connector on your scale is different to mine as the pin layout is different to a DIN connector.

Here are pictures of my plug.



Looking an the Farnell website I think I have identified the connector as a Binder 680 series connector.
This is the Farnell web page for the sockets.

I have also found a chasis mounting socket on ebay eBay item number: 362709678935

They are quite expensive so I think I wil try to make some kind of connector to test the scale. When I know it is OK I will fit a different connector to the scale.


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