Member postings for Martin W

Isopropyl Alcohol can be bought from CPC (Farnell) in either 400ml aerosols or 1lt cans. I always have some around for general cleaning as it leaves a smear free finish and does not attack most plastics though it will affect some paints. It's also good for removing emulsion paint after it has dried, as is methylated spirits, which it useful for cleaning those bits you didn't really mean to paint.

MartinW

John

Welcome to the madhouse that said there are a whole pile of people on here who will be only too pleased to give you sound and valuable advice. I know that there will be interest in your pictures and videos and once here they could well be of benefit to others.

Cheers

MartinW

Hi

If the speed control board drives a similar motor with no problems then the problem is the motor. I take it you are using a Digital Multimeter to measure the volts across the motor and this can give erroneous readings when measuring switched waveforms, even the so called true RMS meters as they are limited to a range of form factors (waveform shapes). If the motor is not running smoothly then as Neil suggested it could be the brushes or the motor connections to the brushes, shorted turns on the armature, carbon build up around the brushes causing tracking to earth. As I said above If the electronics drive another similar motor without any problems then the fault is with the motor.

HTH

MartinW

Hi

The domestic smoke detectors I have running and those which have been replaced are/were all 'ionization' devices. The one near the kitchen had an override as it will activate from fumes from the cooker grill/oven when there is no smoke in the air. That said I haven't checked on the latest domestic alarms to see if they have changed the type of sensor used.

MartinW

PS

Just checked the Screwfix site and they are now offering a full range of detectors including heat and smoke combined. Tomorrow I will purchase a couple, offered in pairs, to fit near the kitchen or even have one in the kitchen. Thanks for the heads up.

Edited By Martin W on 24/03/2019 11:32:18

Hi

There is no need for a transformer as you can buy switched mode power supplies here. They have 24V DC units with output currents that will easily meet the 11A input current for under £30, a 24V 20A DC smps is listed at £28-99p postage included. All that is then required is a speed controller that can handle 20A or so and the jobs done. No need to try and build your own and spend a fortune on large transformers, bridge rectifiers, capacitors and a suitable case to hold it all. Just 2 relatively small units that can be mounted in a smallish enclosure.

HTH

Martin

A suitable speed controller can be found here

Edited By Martin W on 22/03/2019 01:29:19

Bill

You say that the type holder is subjected to repeated heating and pressure cycles. I take it that this happens when tools are used to fix the gold leaf or substitute on the book covers/spines, what is the typical temperature that the print holder is heated for this transfer process? I assume that for the smaller type holders the pressure is only applied by hand and not in some form of mechanical press. The reason I ask this is that Ian has suggested the use of adhesives and these could fail if the tool working temperature is high.

MartinW

Hi

Just printed out one of the photos showing the bezel ring edge on and measured the angle of the bezel to the base and this gives an included angle of 22.5 deg. Before anyone jumps up and down I know that this is not the way determine the 'true' angle on the bezel. I think that SOD by offsetting the top slide by 20 deg actually cut an included angle of 70 deg rather than 27 deg and this would account for SOD's bezel looking very different from the pictures. That said Dave clearly illustrates one method of producing the particular part on a lathe which is what Christopher wanted which was the point.

Cheers

Martin W

They are already being used at airports to scare other birds away, not a in seagull form but as a mock peregrine falcon that perfectly mimics the falcon's flight, glide and attack characteristics. A brief clip can be seen here.

Martin W

Wasn't there an article in MEW sometime ago about springs, spring winding and calculations for achieving the required force, or have my grey cells finally petered out ?

Emgee

Not at all in fact it was FF's comment regarding and I quote, "Amidst all the electronic experts here, this will be inviting ridicule but...."

With regard to your posting I agree that using a neon indicator severely limits any meaningful tests being performed. However if this is all Bill has then use can be made of it to see if the mains supply is reaching the mill and whether physical switches are working. It may also be possible to identify, on the live side of the circuit, where there is a break i.e. Dave suggested that one of the inductors may have failed and it could be possible to identify a fault of this nature using a neon based tester. It's a case of using what is at hand to help eliminate or confirm any problems.

Hope this puts your mind to rest.

Martin W

Bill

If you can do it safely then test the point at which the blue wire is connected/soldered to the pcb with the power on. If the neon lights up then you would appear to have a break in the neutral line to the mill. If there's no reaction then the neutral should be OK and we can discount the supply cable for the time provide the plug has been wired correctly.

FF carbon brush dust build can cause problems but most of the dust is deposited in the motor where it can provide a leakage/short to earth and this frequently causes an RCD trip. If you look at the pictures Bill has posted the actual speed controller board looks to be be reasonably clean and free of any significant contamination. That said I feel that any contribution is welcome as it can make people look again at the problem and this sometimes proves to be very useful.

I think that anybody who just dismisses another's comment as stupid or rubbish not only show themselves up but do a disservice to the forum and can make others hesitant to make a contribution.

Cheers

Martin W

As far as the pictures show the motor doesn't seem to have been over stressed, commutator and windings look to be OK as far as it possible to see and the same applies to the circuit board. I am wondering if it isn't, as earlier suggested, a failure in the mains supply cable near or at the point it enters the head. If this is the case then the machine fuse will have remained intact and the plug top fuse would have taken the brunt and could have blown with an audible pop. This would also fit in with the motor occasionally stuttering prior to the failure as the break in the cable intermittently failed. If the plug fuse has blown then without having the ability to check the cable with a meter it may be worth replacing the supply cable and trying it again to see if there is any response. Another way would be to use a mains indicating screwdriver/tester and after replacing the plug fuse see if there is any indication of the mains being present at the circuit board, no need to say really but just be careful when working on exposed mains.

Cheers

Martin W

PS (edit)

Another possibility is that there has been a failure of the mains switch on the machine which could, remote chance, of shorting something to earth or may have just failed internally with a bit of arcing hence the smell and failure to run.

Edited By Martin W on 31/01/2019 17:48:17

Edited By Martin W on 31/01/2019 18:07:41

Again here is another site with the circuit diagram plus a picture of the pcb identifying the components. Dave beat me to posting as I was rummaging through other pages on the net looking for any other data/information, at least it is not the same site as he has identified.

Martin W

Hi

If you can get somebody to help or have at least have look at it then there are some circuit diagrams here which give the part numbers for the semi conductors and values for the passive components. It would appear that there are two variants one with a very simplistic speed controller and the other a much more sophisticated controller.

Looking at your picture I suspect that you have the former and the rectifier appears to be a bridge rectifier which is probably a fairly squat square unit with 4 wires, at minimum, attached.

Again if you can give us a general indication as to where you are then I suspect will be willing to help. If it's any use I live in Berkshire in the Reading area.

Good luck and hope you get it fixed soon.

Martin W

Hi

I hope that most are aware that there is another scam circulating. Email purportedly coming from the TV Licensing Authority stating that they are having trouble processing a payment. One I received was poorly written and clearly a scam but the other looked convincing and could easily fool the unwary, I believe that there was a case recently where someone lost a fair bit of money to this scam.

The give away is the sender's email address and the fact that I don't need a licence being an old crinkly scrote.

Cheers

Grey/Bald & Aged

AKA: - MartinW

It will be in the very last place you think of looking. How about in an envelope/brown paper in a box in a drawer under the mill/lathe or cupboard on the wall.

I haven't watched the programme yet Michael but are you sure its a tooth and not a bone that he is sectioning? It doesn't look to have the right structure and shape for a tooth.

Martin W

Hi

First of all have you tried talking to Warco re their likely delivery schedule? I have a Chester DB7VS lathe and I have found that for a small lathe it is pretty sturdy and a good work horse; given several years of trouble free service and been asked to do some quite heavy work for a relatively small unit. The reason I bought from Chester is that I saw it at a show and it was available at the time. Both Chester and Warco seem to have a good record when it comes to post sale support and I can confirm that for both companies from personal experience as I have also got a Warco mill.

Do you live relatively close to either company? If so then they normally have their showrooms open so you can look at the lathe you're interested and get a hands on feel for the item.

Cheers

Martin W

The fact that it tripped when the bulb was used as a load tends to preclude a problem with the motor and associated wiring. As Les says if the contacts on the mains switch are not making near enough simultaneously then this can cause the RCD to trip, this will be exacerbated by having a mains filter in the circuit. Another possibility is that there is a capacitor intermittently breaking down or going open circuit within the filter unit. This will cause random failures as the earth currents will not be balanced out. This could be tested by taken the input filter out of circuit and running the mill.

As John R says it's a good idea start at the beginning and slowly connect the bits of the circuit in untilthe fault manifests itself.

Good luck

Martin W

Hi John

I have a few more thoughts about the problem. The fact that you could control the brilliance of a light bulb connected to the output of the power board indicates that the pot is, in itself, working correctly. If there was a break in the track of the pot or problems with the slider then you would have seen the bulb either going from off to full brilliance at some point or if bulb brilliance changed erratically then this could be a dirty/worn track or poor contact with the wiper.

Another check that you could do is to take the pot off the front panel and with it plugged into the control board set the wiper to about a quarter speed setting. Then after ensuring that the pot is fully insulated/clear off any link to earth or other contact switch the mill on and see what happens if you run it. If the mill runs fine at about the right speed then there is a strong possibility that the pot has some form of leakage to earth via the front panel.

The last point to check is the speed sensor itself. This is located under the cover at the top of the spindle, the spindle has a segmented disc and the sensor is an optical, infra red I think, unit that senses the gaps and vanes on this disc. Again make sure that the board etc. is clean and that there is no swarf etc. that could cause problems. If possible it would be worth looking at the connecting cable, where you can get to it, from the speed sensor to the circuit board.

Cheers

Martin W