MemberDecember 8, 2019 at 1:00 pm
My parents stair-lift as title is now showing a Code 11 error on the display (Overcurrent in manual).
The batteries were both tested and cannot sustain a load, voltage collapses very low on both when a small load is applied.
I’m an Electronics Eng (in the power tools field however) but just wondered if there is any common PCBA fault or other fault to look for on this stair-lift?
New batteries have been fitted but as suspected it didn’t clear the Code 11 error.
Appreciate any guidance before seeking an expert.
MemberDecember 8, 2019 at 5:44 pm
I’d check the motor brake is functioning, after that test the current through the motor during travel around 3A down 3-7A up (no load on lift) are you measuring the batteries with a multimeter as they have a tendency to confuse things with the voltage appearing good but actual power available being low. How old is the lift as worn brushes may well be a cause.
It’s always worth giving the pcb relay a tap with a screwdriver handle in case of carbon build up across the contacts or welded contacts.
MemberDecember 8, 2019 at 6:33 pm
Appreciate the reply. Thanks.
I had removed the batteries and checked on an electronic load – Even applying a 1A load one battery Voltage collapsed to <1V and could not even deliver an amp. It measures 8V open circuit. The second battery measured 11V but again any load would just drop the voltage <3V. The batteries are about 5 years old and original supplied.
(The electronic load is a test equipment I use with normal work job). Also both batteries showed bulging signs.
I have replaced them with new Yuasa NP7-12FR 12V 7Ah
If I manually move the chair off the charging contacts (rotary manual accessory handle) I get fault code 2 which stacks up with the manual saying no charge voltage so returning to charge contacts manually then shows the code 11. (Encouraged that there is still intelligence working in system.
There is no movement of the chair motor with with the normal handle switch or remote control.
Lift is about 5 years old but barely used to be honest. My parents purchased it new after my father took ill but thankfully recovered. Its not seen much use at all.
I’ll take a look at the PCB relay, thanks for the tip, When you say the brake function is that part of the relay check or another component?
PCB looks like a right pain to get to. Is there any procedure advised. Do you leave the chair attached to rail?
MemberDecember 9, 2019 at 8:33 pm
The motor brake is a solenoid clutch fitted to the end of the motor via a couple of screws, newer lifts now have an extra interlock switch fitted above the brake to prevent the lift operating whilst the manual winder is in position.
If you place your hand on the brake and put in a call you should feel a crisp click as the solenoid pulls in if its working. Never try to run the lift without the brake fitted please.
The old batteries do sound shot, bulging is never a good sign and five years is getting to the better end of what would be expected for a working life.
NP7-12 are good, FR being fire retarded.
The Pcb is a pain to access, swiveling the seat should give enough room hopefully, from memory there’s a single retaining screw at the top which holds the alloy heatsink in place (don’t drop the screw), the pcb and back plate can then be lifted slightly, you then needs the hand skills of a Gynecologist to disconnect the board, but you can at least see the relay on the pcb.
MemberDecember 10, 2019 at 1:17 pm
Is it defo 11 showing or the little dots either side illuminated….. does the display light all segments when initially powered up ?
the only time I’ve come across over current was when a stairlift tried to drive into a door it stopped and fuse blew…….
contact ur local handicare dealer
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