Hegner scroll saw repair?

[Phil Russell]

I fee quite guilty asking a question on my very first official visit but in reality I do not know where else to turn as an internet search has not revealed answers. I have recently been given a 1995 Hegner variable speed scroll saw. I have no idea when it last worked ... it belonged to the late husband of my daughter and was found while sifting through a workshop. It does not have the clamp lever on the blade fastening though and there are various small tools missing. So it looks like a Multicut 1 but with variable speed. I have a manual from the internet. But the saw does not go. Power gets to the switch in the speed control box, the switch works (removed and tested), the motor turns freely, and as a possible cheap fix, I replaced the start capacitor with one recommended and supplied by Hegner (8 microF). There is no motor hum or any other noise on switching on. The oft recommended 'bump start' does nothing.
Is there a way of saying which part has failed? Motor or speed controller? I baulk at the price of spare parts but who knows, a s/h part may crop up. I failed to find circuit digrams for the motor and controller. Does anyone have another suggestion as to what might be wrong?
All advice would be appreciated.
Regards
Phil

 

[sunnybob]

if you are ok with simple wiring tasks, just by pass the speed control as thats most likely the culprit.
If the motor only has two wires into it, then live and neutral either way round will spin the motor.
Then you can find a cheap alternative make speed control.
When you turn the motor by hand are the arm joints moving freely? Is it just seized bearings on the arms?

I've just acquired a similar vintage multicut 2 but all of mine is in working order apart from the air blower, and I am NOT paying £23 for a plastic bellows, so an aquarium pump will do that job for about a fiver

Hegners dont come up for sale very often, but be careful not to just buy parts at their silly prices because you could soon have spent more than a whole machine.

 

[Phil Russell]

Thanks Sunnybob.
The arm moves freely ... motor does not turn even with the arm disconnected.
I will have another look at the motor wiring ... that would certainly indicate if the speed controller was the culprit.

In the meantime ... any more pointers?
Cheers, Phil

 

[sunnybob]

Phil, 99.9% its the speed control. Bypass it before stripping the motor.

If you dont have the key to tighten the blades in with, its a standard clock key.

 

[Phil Russell]

Thanks again Sunnybob.
I have just removed the speed controller cover again with the intention of hooking up the motor direct.
There are 4 wires going into the motor at what I believe is the business end. There are 2 more much thinner wires going into the 'fan end' which I assume are not involved here. Maybe they are some sort of speed indicator?
One of the main wires (red) comes off the start capacitor but I am not sure which of the other wires does what. They are white, black, and green and all have spade connectors to the edge of the pcb. My guess is they are power wires due to their thickness. This is where a circuit diagram would be useful in order to identify the connections to give power direct to the motor. I am reluctant to just try any wire without prior knowledge and do not really want to strip the motor out.
Motor is an AEP 56 B-4-ER
I wonder if a google for the motor may throw up more information.

So .. does anyone know the wire colour coding for the motor?

Cheers, Phil

 

[sunnybob]

we 're stepping past my knowledge base now without having the motor in front of me.
The two thin wires are either an overheat switch or a centrifugal switch, which could be your problem, but I havent had mine apart so am not sure. you will have power on one of those leads at least.

Sudden thought.... have you checked for a reset button? little red doo dab somewhere? Just remembered theres one next to the speed controller on mine.

I am about to go out for the evening now, but if no one else comes along in the meantime, I'll be happy go into the garage to take off the covers on mine tomorrow and let you know whats what.

 

[Phil Russell]

Thanks again ... no reset button.

I have tried googling the motor type but no luck with a circuit diagram.

Enjoy the evening, Cheers, Phil

 

[scrimper]

Be careful with that motor! It is not a motor that is controlled by any old type of speed controller. Hegner uses a special induction type motor which needs a special speed controller, most normal 'bog' standard speed controllers only work with universal series wound motors (carbon brush motors) which are fitted to many machines.

I am not saying the speed control is not faulty just saying that you cannot replace it with a bog standard controller and be careful trying to bypass the controller on this type of motor unless you are 100% certain you know what you are doing or you will damage the motor for sure!

Induction motors are better, they are quieter with less vibration and much more reliable but more costly, I would be surprised if the one on your machine is worn out but it is not impossible, are you absolutely certain the on/off switch is OK? It is a very small switch and not very heavy duty they often have poor contacts which being switched on and off a lot arc and cause intermittent connections, have you tried by passing the switch?

I am not sure of how the speed control is wired on the Hegner, I have the variable speed model and I have changed the switch on mine but I did not notice how the speed control was wired at the time so I can't advise on the actual wiring of the thing without studying mine again.

(FWIW I do have experience on repairing electrical and electronic equipment)

 

[Lons]

Hi Phil
my multicut 1 vs is excellent though still very new. My opinion is also that it's likely to be the on / off switch or VS controller. Have you considered giving Hegner a ring. I spoke to them several times with questions before I bought mine and found them more than helpful. I spoke to a tech guy and of course was a potential customer but nothing to lose surely!

Bob

 

[sunnybob]

Phil, heres the inside of mine. I must have had a couple of pre party drinks last night as I was mistaken, there is NOT a reset button on it.

Like scrimper says, thats not a normal (cheapo) controller, dont try to bypass it.
Just to check the wiring is the right way round, heres how mine works from the top left;
post 1 is to the capacitor, and the return wire connects to the motor red wire.
post 2 is green to motor
then post 3 is black and then post 4 is white to motor.
The mains is wired neutral to the left and then live. make sure the mains is the correct way round if the cable has been replaced.

That switch is very small, and yes, you can bypass that quite easily.

Let us know.

 

[Phil Russell]

Thank you all for your help and advice. Rest assured, I have done nothing yet regarding a possible bypass. The switch is fine .. I have removed it and tested it.
From what I managed to find out on the web and maybe accepting the obvious from looking at the present controller, the motor and control unit are quite complex with, just maybe, the controller containing an inverter circuit (? this is mentioned in several indiction motor threads elsewhere). This is getting beyond me at this point ... the last time I dabbled with major electronics was when I used to repair our 405 line TVs. We often had two sets working, one for sound and one for picture. I understood my way round them then. Add to the fact that Hegner use a different motor for single speed and variable speed units and maybe that suggests a major difference between them.
I have sent a question to Hegner Technical asking if it is possible to tell which part is broken, motor or controller. I would expect it possible to test the motor by bypassing part of the controller but maybe not. Maybe there is a way of checking continuity in the motor windings using a simple multimeter? Or checking point voltages in the controller itself. Again, this is verging on my technical knowledge limit for units such as these. My research leads me to believe there will be some form of switch in the motor, (centrifugal switch?) to take the start capacitor out of circuit once the motor gets to a certain speed but I doubt if this could be an issue ... and I might be talking absolute rubbish here. I am most reluctant to start taking the motor apart as bearings can be an absolute pain.
In the meantime, I am most grateful for all the comments, especially Sunnybob for taking time out to photograph the interior of his controller. Mine looks the same by the way.
If and when Hegner reply I will report back although I do not expect them to tell me how to test the units for safety reasons and to most likely advise me to take the machine to them for possible repair ... we will see.
So for now, enjoy Sunday.
Cheers, Phil

 

[novocaine]

take the motor off and spin it by hand with a MM across the poles, it will back feed.

check that rather large capacitor in the above picture (the white bit at the back). bet there is also a thermal fuse in there somewhere, both worth checking for continuity.

 

[Phil Russell]

Update:
I did hear back from Hegner:
start: My sincere apologies for the long delay in getting back to you, a very busy time of year and to top it I have been out of the office all week on deliveries. Personally I’m not sure
of the correct wiring setup to test the motor directly but I have included some photos and a diagram (in German) which I hope may help you and shed some light on this.
Just to infrom you that we do offer an HM-Inspection service for Hegner saws, should you wish more information on this service then please do not hesitate in contacting my colleagues as I am out of the office again until Friday this week.

If I can offer any further help or advice, please do not hesitate in contacting me. END

The photos they sent were for the single speed motor, so not much help. The diagram was a diagram of the component side of the circuit board for the variable speed controller giving the reference numbers for the components but not the component values. Useful though.
Taking the suggestion of 'novocaine' (thank you), I replaced the large capacitor but it made no difference ... still dead. It was worth a try though.
I did reply to the Hegner note asking if they had any more suggestions and if they come back to me I will report again. As I only intended to try this saw for fun I have no intention of spending a lot of money on it as it would be a waste to me, so I am thinking that my best course of action is to sell it 'spares or repair' as I am sure my daughter could do with the funds. I am thinking in the region of £120 collected from Cambridge ... I guess there is no harm in trying the on-line sales sites.

In the meantime, I thank you all for your contributions.
Cheers, Phil

 

[Clockie]

After 8 years of use my hegner multicut 2 packed up. First the speed controller failed, I the had it rewired to single speed by an electric motor specialist, after 8 months of use the motor burnt out. I have been without a saw for 12 months because I refuse to concede to hegner prices.
The two odd wires that you refer to are from the tacho that are part of the speed control. I was going to buy a standard 56 frame motor off ebay which will fit but hegner use a non standard size shaft diameter. The standard is 8mm and hegner use 10mm, therefore the fly wheel would have to be re-engineered. The prices from hegner for electric motors are jaw dropping.
As an aside I was told by the engineer that the reason for premature failure was the use of a floor switch and leaving the speed control on max. Instead I should have discontinued the use of the floor switch and always brought the speed up to max on the dial knob

 

[scrimper]

After 8 years of use my hegner multicut 2 packed up. First the speed controller failed, I the had it rewired to single speed by an electric motor specialist, after 8 months of use the motor burnt out. I have been without a saw for 12 months because I refuse to concede to hegner prices.

Sounds like you have been very unlucky with that motor, I spent most of my working life in the electronics/electrical business with 25 years repairing domestic appliances and I can say it is very rare to have trouble with induction motors, they are generally extremely reliable by virtue of their design, The same cannot be said of series wound or carbon brush type motors which are much more prone to problems.

 

[Phil Russell]

Well, having considered all options and given the cost of new parts and the fact that I am not a hardened scroll sawer, I decided to sell the machine 'spares or repair'. This has now been done and the sale proceeds passed to my daughter.
In the meantime, thank you all for your help and encouragement.
Cheers, Phil