Braun Alarm Clock AB30vs Repair

I was lucky to find a book on the complete works of Dieter Rams by Klaus Klemp under the tree at Christmas. Much has been written about the influential product designer and his collaboration with Braun and Vitsoe. One thing that resonated with me from the book was Dieter Rams own words in the foreword about the future of product design and the need to ensure things can be repaired rather than discarded after a forced short life.

So inspired by Rams words and the copious images I looked around the workshop and found a Braun travel alarm clock that has been waiting patiently for repair.  A fresh AA cell found the beep, beep, beep alarm sounded and instantly hushed with a short sharp shout ‘stop’! The alarm clock, a type 4763 / AB30vs did not tick and was missing its green control to set the alarm so needed some attention to restore.

Inside, there’s a simple plastic movement and a quartz crystal circuit that drives the electromechanical cog wheel mechanism. There are four grey electrolytic capacitors that I suspected may have lost their capacity so I decided to remove the small circuit board and check.

Braun Travel Alarm Clock type 4763 AB30vs inside view

Two cross head screws hold the PCB in place but the clock hands need removing first. The hands are behind the clear plastic dial face which is released from two small slots inside either side of the PCB. It needs firm pressure from a small flat bladed screw driver to carefully prize the dial free. I set all the hands to 12 o’clock before removing so they would be in the same position on reassembly but it does not matter as they are all relative.

Braun AB30vs front face removed to access hands

Underneath the PCB revealed a surprising mass of surface mounted components. My version of the AB30vs was at least a  third edition, the original, produced in the 1980s has a separate board for the voice activated alarm (see epilog) but here all the necessary devices were now hidden underneath.

Braun AB30vs underside PCB

I used an oscilloscope to check the crystal was resonating and see if there was an output driving the actuator coil. I found both. A pulse every two seconds was emitted and could be seen on a simple voltmeter if you don’t have an oscilloscope.

I guess a two second duration is chosen rather than every second to reduce battery drain. But why was the clock not ticking? Still suffering from a glass or two of bubbly I foolishly started checking the electrolytic capacitors and the junctions of the diodes and transistors. I even removed one of the caps to find it measured exactly the correct value. Hmmm.

One of the traps I fall into when diagnosing faults is to jump to conclusions – hunches – rather than follow logic. The electronics were working, the mechanics were not. So I removed the plastic cover that holds the cogs in place. There are two central lugs which release the cover with a very careful twist from a screw driver. The plastic is fragile so do go gently. And remember that when it opens suddenly cogs are likely to fly out (the small black one is missing in the picture below).

Braun AB30vs with broken stator pin

All looked fine under the cover until I removed the smallest red cog stator that’s driven by the actuator coil. It left behind a tiny red plastic pin that should have been attached – see above on right hand side. This was why the tick did not tock. I used some fine tweezers to remove the pin. A small dab of PVA may reattach it so I reached for the glue and placed a tiny spec on the end of the stator magnet.

Braun Travel Alarm Clock AB30vs showing stator with missing lower pin bearing

I then picked up the tiny plastic pin in the tweezers and moved it towards the glue. Ping! The pin disappeared as it sprang from the tweezers. Oh well, I looked around and after a few minutes found it sitting on my chair.

Second attempt. I moved the pieces to a clear desk and set up a better light and finer tweezers for more control.

The glue had started to go translucent so I placed a fresh speck of PVA on the pin and gently moved it to the stator centre. Ping! It flew away from the fine tweezers with greater velocity. I searched the desk, floor, shelves, well most places I thought it could have landed. After 45 minutes I decided it was lost.

Okay, so what would Dieter Rams do? Go and buy a new clock? No. I looked around for some thin plastic to make a new pin. A nylon broom offered a solution using one bristle. I cut it to size, profiled the end to a slight taper and glued it in place and left it to set overnight.

Braun AB30vs nylon bristle repair

Next day the glue had hardened and I tried it in place. Too big. I cut a millimetre or so from the length and using fine sand paper I gently profiled the end. It snapped off.

Oh well, what would Dieter Rams do now? Try again. So I rethought it. The glue is not strong enough to allow shaping after attaching so I need a stronger joint. So I wondered if the red plastic that passes through the centre of the magnet was thermoplastic and would melt with heat from a soldering iron. I found a thin wire lead from a resistor and applied heat mid way up one lead while holding the other end. I then pushed the hot end into the stator centre. It melted and a small collar of plastic formed around the wire. I let it cool and using fine wire cutters trimmed it to length so the red cog wheel aligned with the same height as the other cog pins.

After replacing the clear cover which aligns the cogs I tried adjusting the time control to check the cogs moved as expected. They did. And with 1.5v supply the clock started beeping and began ticking again.

It’s been going for over an hour now as I type these words so too early to say if it’s a permanent repair but after all the searching it is working again and even stops beeping when I shout Rams!

Epilog

If you come across a similar Braun analog clock that fails to tick it may be repaired so don’t just throw it away. Ram’s design is more than skin deep. While it’s probably likely that newer Braun designs are less easy to repair, this example has some service in mind. The front face has access slots to allow removal as does the clockwork mechanism. The electronic components can be serviced albeit with a fine soldering iron on this surface mount version. The original AB30vs with its separate voice control circuit board is easier to service.

While searching for the circuit diagram for the AB30vs we stumbled upon this post from a fellow enthusiast in Germany. He managed to restore an earlier version with simple application of cleaner and lubricant see Wecker Braun 4763 AB30vs. (opens in new tab – and open in Chrome if you need to translate from German.)

We also found some examples of the versions Braun have produced over the years. This one from WorthPoint – BRAUN DESIGNER ALARM CLOCK 4763/AB 30 – is I guess slightly older form of quartz crystal and 8 pin integrated circuit logic. (I’m saying we as my long suffering wife kindly searched for schematics after I’d complained Google was hiding the information.)

Another version from WorthPoint – BRAUN VOICE CONTROL AB 30 shows the separate PCB for the voice control along with a larger clockwork mechanism housing the quartz crystal logic.

The AB30vs is a perfectly good design, light weight, simple to power – using  one AA cell widely available and simple to use with no fiddly push buttons found with digital alarm clocks. With voice activated snooze, luminous dial hands and repairable with some perseverance could the design be better? Rams would say Less is better.

Yes it can and should be better, the version I had failed due to poor mechanical design. The lightweight plastic clockwork mechanism with its fragile plastic stator pin is too weak for the weight of the magnet. Given the alarm clock is sold with travel in mind it’s very likely to get dropped sometime in its life and a fall could easily break the stator rendering it inoperable as likely happened to my clock. It would be interesting to see if the original 1980s version has the same weakness or if the evolution to cut production costs and boost profit is to blame.

Should product designers consider more user journeys for their products, like we do in software engineering applications? Well some may say that’s what good designers have always done. Form follows function as Christopher Alexander suggests in is Notes on the Synthesis of Form and this medium is the message as Marshall Mclulhan once said.