These chargers often lead a hard life, working in dusty, hot and noisy conditions, so I guess many of these fail in time.
This Bosch unit is fairly common among Bosch DIY drill sets and this one had died catastrophically. With the power applied, this one refused to give the slightest charge to a drill battery, once plugged in.
After some basic testing, I decided to change four components which would have caused the other to fail in a ‘domino effect’. The cost of the replacement parts was just shy of £10, but definitely worth saving since second-hand units seemed to be changing hands for £40 on eBay, with their condition largely unknown. The parts (two resistors, MOSFET transistor and diode/ transistor) were readily available online.
I recorded a short video to help others who might have a similar problem with theirs…
The owner of this drill complained that it work perfectly one minute and then stopped the next. It was making DIY a very slow process.
As this was a cut-out problem rather than a slowing down issue, power problems were a likely suspect.
On test, the cable flex near the base of the handle seemed to be the issue as giving it a good wiggle seemed to reproduce the fault.
Opening up the drill (several self-tapping screws) revealed a fairly straightforward layout with cord, mechanical connector, smoothing circuit (mains splash) and switch. Having suspected the culprit to be cable flex near the handle, I cut the cable down and re-made the connection, removing the suspect part of the cable.
Despite cutting the cable flex down by about 8″, the owner was pleased with this fix since no spare parts were required and no real issues will be noticed since it will be mainly used with an extension lead.