Background
I purchased this electric toothbrush in 1999. I used it continually until 2006 when i upgraded to a more modern model. I kept this one as a standby/spare and when traveling. Gradually the charging time got longer and usage time decreased until about 6 months ago the toothbrush no longer charged so i put it aside intending to look at repairing it. Now i have finally got the time to look at it. As long as the internal mechanism is in good condition it would be worthwhile repairing the toothbrush as a comparable replacement
The charger unit has a plastic tab which is used to remove the base of the toothbrush allowing the internal parts to be removed.
This picture shows the toothbrush after the case was opened and the internal mechanism removed.
The battery(yellow parts) can just be seen behind the control circuit board.
Here the toothbrush has been dismantled into its component parts.
The battery terminals were carefully desoldered from the control circuit board which allowed the battery to be removed from the internal body.
The gearbox mechanism was removed from the top of the motor to allow it to be cleaned and greased if required.
The charging coil can be seen in the top right of the photograph beside the battery.
Although this battery looks to be a single one piece unit it does in fact consist of 2 x 2/3 AF size batteries connected in series to produce a 2.4V unit. The terminal voltage when it was removed was zero volts. There were also a lot of white crystals on the terminals indicating that the battery had been leaking.
The battery terminals were carefully desoldered from the control circuit board which allowed the battery to be removed from the internal body.
The gearbox mechanism was removed from the top of the motor to allow it to be cleaned and greased if required.
The charging coil can be seen in the top right of the photograph beside the battery.
Although this battery looks to be a single one piece unit it does in fact consist of 2 x 2/3 AF size batteries connected in series to produce a 2.4V unit. The terminal voltage when it was removed was zero volts. There were also a lot of white crystals on the terminals indicating that the battery had been leaking.
I ordered a new battery pack on line and it arrived 48 hours later. I checked the condition and battery voltage and all looked well. The battery cost GBP6.00 including postage and packing.
I had to desolder the circuit board to get the positive battery terminal into the small slot on the circuit board where it attaches to the motor.
The battery terminal tags were much longer than required.
The positive tag was cut to length and then the width trimmed so that it would fit the slot in the circuit board.
The negative tag was cut to length and folded over the end of the circuit board.
Terminals were them carefully soldered in place using as little heat as possible so as not to damage the battery.
It was now possible to test the tothbrush before reassembling it into its case. It worked exactly as expected.
The positive tag was cut to length and then the width trimmed so that it would fit the slot in the circuit board.
The negative tag was cut to length and folded over the end of the circuit board.
Terminals were them carefully soldered in place using as little heat as possible so as not to damage the battery.
It was now possible to test the tothbrush before reassembling it into its case. It worked exactly as expected.
The rubber seals and inside of the case were cleaned to remove toothpaste debris. The gearbox looked to be in good condition and did not require any further greasing so the mechanism was carefully put back into the case and sealed up.
I then tested the toothbrush leaving it running for 5 minutes.
Dismantling, repairing and ordering the parts took a total of less than 2 hours. The replacement battery cost GBP6.00 where as a replacement toothbrush of comparable type would typically cost 3 times that amount so it was well worth the effort repairing it afterall the rest of the mechanism is still in perfect working order.
The original battery was a Ni-Cd type. The replacement type is a Ni-MH type. I found it impossible to get replacement Ni-Cd in the required size. The original charger will still be used and should present no great problems as the charging current is small however i will monitor it over the next six months.
The original battery was a Ni-Cd type. The replacement type is a Ni-MH type. I found it impossible to get replacement Ni-Cd in the required size. The original charger will still be used and should present no great problems as the charging current is small however i will monitor it over the next six months.