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Stannah 420- Power light off
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My mother has had this lift for around 8 years and until 3 years ago it was regularly maintained by Stannah.
She moved in to a nursing then and lift was working fine. Have been testing it every week since and it was working fine till about 2 weeks ago.
We are now having to sell the house and were going to try and find a new home for the stairlift.The green power light is off.
I have checked, the power switch on the arm, the keyed power switch and the battery isolator switch.
I have checked continuity of the wiring from these switches back to the main pcb.There is power getting to the batteries and there is around 28v across those batteries.
If I can’t repair this it will have to be scrapped as it would cost more to have it repaired professionally that it would subsequently sell for.
Can anyone provide a wiring diagram for this model or does anyone have any ideas what might be causing this?
Many thanks for your help.
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Have you checked the isolator switch on the back of the carriage, in the off position you’ll hear a click if you press on the top safety edge, in the on position there will be no click.
This click is the motor brake being energised for hand winding, you could try hand winding he lift away from the end of the rail by a few inches before turning it back on, there’s a chance that it has over travelled slightly.
If you remove the plastic cover between the seat base and the footrest you’ll hopefully find a circuit diagram fixed to the back side. -
Thanks for your reply Kevin.
I had switched the battery isolator switch on and off and also moved the lift with the had winder quite a way up and down.
None of that made any difference.
I had the cover off you mention to access the switch wiring when I was checking the connectivity but all I saw was the maintenance record filled in by hand. I suppose the circuit diagram could be under that, I will have a look when I visit again in a few days.What exactly do you mean by the “top safety edge”?
And what could it be if I do not get a click in either position?
Thanks again.
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If it clicks then it means the lift has been switched off on the rear isolator switch, if not then hopefully it means the lift is powered up. No clicks mean that the batteries aren’t connected.
Top safety edge is the metal plate on the up side of the carriage which surrounds the rail. -
Thanks,
I’m pretty sure the batteries are connected as I metered them to check their voltage and connectivity but will double check tomorrow.
I have definitely had the rear isolator switch in both positions and no matter what position all the switches are in the green power light stays off (and the lift does not work).
If the batteries weren’t making a good connection and they are fully charged would that stop the green power light from coming on?P.s. Just worked out what you mean by safety edge and I definitely remember them clicking (both top & bottom ones) but can’t remember whether that was when I had the isolator switch on or off, will have to double check that tomorrow.
If they are clicking with the isolator switch in the on position could that mean the switch is faulty or some other power problem like the pcb failing?
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You’ll hear a different sound when the up side is pressed in with the rear isolator switched off, that being the motor brake releasing.
Other clicks you hear will most probably be the switches activating behind the safety edges. -
Circuit diagram where you said. Thanks.
top safety does not activate brake but bottom safety does.
still no power.
any ideas?
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F1 appears to have blown.
will replace and update here.
Any idea what mighthave caused it to blow?
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F1 control circuit, means that a part of the safety’s circuits have been shorted to earth,
follow diagram on the panel with a multimeter. She sure u use the same current capacity fuse on its replacement… it’s I think 250ma quick blow ( not near manuals at present) -
Thanks, will try that tomorrow.
F1 is 500mA T HRC (PART No. 901148) according to circuit diagram.
Have same ready. -
Replacing F1 fixed it.
Will monitor for re-occurrence.Thanks to Kevin & Clive for your help.
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Most common cause of blown fuse on 420 is swivel switch wires chaffing on swivel levers. If you strip seat off and remove bottom plate via torque screws you can check this if it is the cause it will be visibly obvious
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