Results tagged “RepairCafe”


A little over one and a half year ago we ordered a bunch of LED floodlights to improve the illumination situation in our basement workshop rooms for the Repair Cafe events. Prior to those floodlights there were about 12 spotlights each with a 200W bulb. Despite the number and wattage the lighting situation was suboptimal and at each event we had to add four 500W halogen floodlights to reach acceptable work conditions. Totalling at more than 4kW this was quite straining on our power lines, heat up the rooms quite a bit and caused frequent overloads and power outages, especially if other devices with a high power consumption were in repair attempts. So we decided to replace half of the spotlights by 50W LED floodlights to cut down on power consumption and increase the overal illumination. Over a few weeks we evaluated a few floodlights (because not only wattage was important but also that the light color fitted into the existing light situation) and settled on a set of good warm white 50W LED floodlights. The illumination was much better than we imagined and in full setup used only 1.5kW of power. Less than half of the usage for what we can only describe as a near-daylight situation in our rooms. Very nice :-)


Near the end of 2016 one of the floodlights began acting up and had to be taken out of service. When turned on it was fine for a second or two but after that it began flickering like mad.

Of course this was unacceptable and while we had to replace it with another floodlight for the time being the concept of the Repair Cafe is to repair broken stuff. And that's whar I decided to do with this one. From the behavior I initially guessed that probably the power supply had broken but as I later found out that was a red herring.


At first I opened the back with the power supply but that did not result in progress as the incoming cable and outgoing ones to the LED element were all isolated and had (without damaging it) no possibility for putting on multimeter measurements. So it had to happen on the LED element itself. Opening the front of the floodlight was also not really an issue. Just four screws at the frame and four screws on the reflector and the LED element with its connectors was accessible.

On a first glance not too bad and rather clean but upon closer inspection:

Oh wow, one of the LED elements screws seems to have been messed up during installation and they fixed it by using a piece of wire and some force. Well, it seemed stable so I did not care about it too much. But then I recognized those little gems:


Nice, some solder balls rolling around in the case. Veeeery bad. I cleaned everything out, checked that no shorts were present and re-tested the light. No improvement but I recognized something different. I pulled out my power supply and tested the LED element directly:

Oh wow, it seemed like the LED element itself was the culprit. It was not visible when the light was plugged in because of the sheer amount of light but when brought up just with minimal supply voltage by an external power supply it became apparent that half of the LED stripes in the element had failed and when brought up to higher voltage also all but one ceased to work. I now assumed that the power supply in the floodlight had some sort of failsafe mode and turned off temporarilly when the LED element drew an abnormal amount of power, causing the flickering.
I changed my approach and ordered a 7$ 50W warm white LED element from eBay. All of those have identical dimensions and comparable power supply specs so it was relatively easy to find one. I went for an element with a bit larger metal base. I chose that one to improve the heat distibution to the floodlight case and let the LED element itself work with a bit lower temperatures.
In my experience most LED elements nowaday fail because of problems with heat distribution.


After a week or two the replacement LED element arrived and I could finally start with the repair attempt. After unscrewing the old LED the lapse with one screw during assembly was visible in its whole beauty.

I then began preparing the element for desoldering. Lifting it from the case was important to reduce the heat loss, therefore I lifted the element with some paper.

And just before desoldering I remembered to check the new element once more and mark the polarity so that I do not accidentially solder it backwards.

Finally everything ready I fired up the solder station with the largest tip I had around. This took a bit and called for a short break.

After the Mate the desoldering began and unexpectedly required higher solder temperatures than I expected. The solder was a bit reluctant to come off and I had to turn up to 350°C to get the wires off.

Following the removal also the old thermal compound had to be removed. Quite a mess but finally with lots of paper towels and Isopropanol I got it relatively clean.

Next up was preparing the wires for the new element. That meant removing all of the prior solder, extending the contacts a bit and tinning the wire tips.

Followed by the soldering of the replacement LED element. Don't forget to use plenty of flux for proper contacts.

Cleaning the element once more and finishing properly was done. This also included the backside of the LED element, I didn't rely on a clean surface there either.

Preparing for the first test after replacement required some additional checks. I visually checked if there were no solder balls around and checked with a multimeter if all connections were ok, earthing was correct and no shorts present.

The first test was done quickly, only leaving the element turned on for a few seconds. There was no thermal compound yet and the LED was not tightly screwed on the case. I expected the heat to build up quite quickly that way and so I had to hurry too. The test was successful. Just during the cooldown of the element I recognized a single LED inside the LED block to be darker than the rest (visible for a short time in the middle of the LED element) and checked visually if it was working and no aparent damage present. Everything looked fine there so I continued.
(ignore the background sound, I was watching some Youtube during the solder job and forgot to turn it off...)

Properly adding thermal compound and making sure that there were no air traps inside took a bit of patience. For that I put a large drop into the middle of the case and lowered the new LED element with circling motion. When it was down I pressed with a bit of force until the thermal compound was spread visibly on all edges of the LED element.

Screwed everything tightly, also re-adding the fix for the messed up screw. And another round of cleaning again. I should have probably waited for this step for thorough cleanings, could have saved me a few minutes in the prior steps. I didn't expect the prior steps to create that much mess again.

After that I did a visual check one last time if everything was tight and rigid, screwed in the reflector and screwed on the glass frame. Looked exaclty like before the repair procedure.


The (almost) final test was satisfying. The flickering/pulsation was gone and everything looked fine, just of course a bit brighter than with the old element. The following final test was to let it sit there turned on for two hours and check the temperature. The case didn't heat up too much, the light intensity didn't change and all individual LEDs in the LED element were still functional.


In the end the whole procedure did not only require a replacement LED element worth only a few € but I also had used more of my repair equipment than I expected. Of course the repair would have been possible with less equipment too but some steps would have required a bit more accuracy and patience. The repair attempt itself was successful and the floodlight is now working as expected. Probably even better than originally as I removed some loose solder balls and undertook measurements that the heat from the LED was dissipated as good as possible.
Used tools:

  • power supply
  • banana plug wires and crocodile clips
  • solder station
  • solder (leaded)
  • solder sucker
  • multimeter
  • solder tip cleaner
  • solder flux
  • wire stripping tool
  • screwdriver with bit
  • isopropanol
  • cotton swabs
  • marker
  • thermal compound
  • third hand tool
  • Cliff Quick Test tool (for safe checking of bare wires with 220V supply)

Oh wow...

Who would have thought, that there will ever be another posting at this blog after such a long time of silence. Well, now the silence is broken again, at least for this post and hopefully some more in the future again.

So what was the main reason for the long silence? To make it short: the Repair Café in Graz. After the initial successes it really took of like no one of us expected. By end of Jan 2017 we held our 22nd Repair Café event in Graz. I'm pretty that our location organizes the biggest events in Austria with 145 repair attempts during the last event alone. While this keeps being exciting all the time it also takes quite a lot of time to organize one event and do all the behind-the-scenes stuff in between. And that's mainly the reason for my reduced online presence. We also helped several other locations in Styria to start their own Repair Café events and I'm always trying to be present at as many as my tight schedule permits. Furthermore we got in contact with officials and many other initiatives working on social and environmental topics.

Were there any other major changes apart from the Repair Café? Sure, too many to count. But for a glimpse and completely unsorted:

  • focus changed from computer/programming to repairing and hardware tinkering.
  • blog webserver has been migrated to new hardware and hosting platform, backend engine updated and upgraded to HTTPS
  • home heating system upgraded to include a proper buffer tank and access to the underlying control logic (squeezing out another ~30% efficiency compared to the state when the plumbers considered it finished)
  • at daily job: changed positions and project assignments at my employer a few times, always trying to not let loose on quality and security issues on each assignment

Well, that's it for now again. I hope I find the time to post more regularly in the future. Some interesting topics are already circling in the back of my head.

Update: I just realized that the last activity on this blog had been EXACTLY 3 years ago, almost to the hour. This was not planned but is a nice coincidence :)


Sorry again for the lack of updates. There have again been several important personal things to deal with which took their time and did not leave enough spare time for something else. Among these were (and still are) things like helping my brother and his girlfriend moving to their new home or trying to organize and compare offerings for a thermal energy storage upgrade of the heating system in my home.

But for me personally most important was the unexpected gain of popularity and need for communication related to the RepairCafé. This has been caused by a full-page newspaper article that was published a few weeks after our second RepairCafé. After that article there have been numerous contact requests and inquiries. Apart from simply explaining details of the RepairCafé this also involves networking and bringing people in touch with each other for cooperative intermediate repairs. Furthermore we're working on enhancing our online presence and planning future events.

We decided for now on an RepairCafé event every other month, with Nov. 23rd being our next date. Additionally we're planning a coop-event with the environmental department of Graz the day before. As this coop-event will take place at a shopping center it will be a large public appearance and there are numerous things to prepare for that. One of the things is to organize some helpers which can be present there and cover the whole day as well as finishing up our homepage and preparing some material to show at the event.

Bear with me, I'm trying to come up with more postings but time is currently a rare gem again.


Last Saturday the second local RepairCafé took place. While the first RepairCafé had a slow start and not many repaired goods to present afterwards this second time was a huge difference.

This time was a larger group of helpers and interested people and also much more success in repairing stuff. There also was a short visit by a journalist from a local newspaper and maybe an article will be written. The success stories range from walking sticks on the simpler side (took only seconds to fix) to replacing a dead battery in a MP3 player with a transplant from another broken player. Radios, remote controls and cameras have also been taken care of and are now also in a completely usable and working state again.

I'm really happy how this initiative has developed and in my opinion it is a great success so far. I'm very thankful for all the people who helped me to bring to live and hope the pace and support will keep up and spread even more.


The last few weeks I've been busy organizing a local RepairCafé. A RepairCafé is an event where a group of private persons meet and try to fix broken everyday stuff. Everyone is invited to visit and take broken items with them to repair them together with the people present, watch them (and learn) repairing the goods or just have a nice chat.

The idea for organizing a RepairCafé came to me several weeks back when I read about it somewhere on the Internet. Shortly after that I visited the Barcamp Graz 2013 where I had a talk with a group of other interested people and decided to take on the task and try to set up such an event in the near future (see also this post from May).

Well, some meetings and many new connections and contacts later, last Saturday the first RepairCafé took place at the Traumwerk open shop together with a clothing change event organized at the same time. We chose that event to attract some more people than we could reach independendly from each other and I think (at least from the RepairCafé position) this worked quite well.

There haven't been so many people who took the chance and brought in broken stuff but there was a bunch of people who just heard of the event when they were already there. And it seemed to be an interesting idea to most of them so that we were often asked how often this took place or when the next event is planned. Not too bad I guess.

Currently I'm finding a date for the next public meeting to have a short recap on Saturdays event and plan or discuss our future steps.


I don't exactly know why but in the past month I somehow did not find the time and motivation to create a proper post but several things have happened and this is just a quick summary over them all.

This may or may not be followed by individual posts on each single subject. I hope that I get around to that but no guarantees. So lets get it on.

On the LED Cube front I hinted on a "recent technical acquisition" in my last post on that subject. Well, this acquisition is nothing less than a full blown digital oscilloscope. YAY. It took a few weeks to decide and also a few days to find a suitable distributor but now I'm a proud owner of an Owon SDS7102V 100MHz digital scope.

The next notable gadget I (finally) received is the long-awaited Pebble watch. Within two days this little gem became the most notable thing which I didn't know I have been missing as companion for my phone for a long time. Despite some bad reviews on other places, I've been expecting an "extension" to my phone's display and that's exactly what I got. No need to long for the phone in my pocket anymore when there's something up. Within a second I know what's up and can still decide if I should take out the phone or just ignore a received spam mail until later. Furthermore much less distraction for other participants in case of meetings. Currently I'm mainly using this Star Trek inspired watchface for displaying the time and I also have installed Pebble Notifier on my phone to forward notifications of some selected applications to the watch, even if these aren't natively supported by the Pebble app itself. Great tool. And it's quite exceeding the expected runtime, my current record is set at 10 days without recharge (and that's before I discovered the option to not turn on the backlight when there's enough ambient light).

I also attended several events. The first one was the Grazer Linuxtage which is a mixture of project exhibition and series of lectures all centered around Linux. Like two years ago, where I also attended, the lectures were quite interesting and I hope that I find some time to try out or have a deeper look at some things I noted down during the lectures. The only negative point of the event is that the place is getting much too small for this event. Many of the lectures I attended that day were so crowded that late-comers could not even enter the lecture hall anymore. I hope that this changes in the future.

One followup-event which I got notice of on the Linuxtage was a (Linux) Show and Tell at the realraum Graz. At this event people showcased their favourite or special Linux tools, i.e. special use cases and capabilities of SSH. Before that event I thought that I'm not that bad with the Linux console, but I've been pretty much floored by the experts there. Which is not necessarily as bad as it sounds because at least I understood everything the guys were talking about :)

The barcamp Graz was the next event which I visited. That time this was a three-day long event and luckily I could be there all days. A barcamp is like a conference just with the difference that every attendand is a participant and presenter. The detail topics of the sessions are not planned before but are decided on and ordered by all participants at the start of each day by themselves. It was a very interesting experience and made it possible to have a look at many different topics from many different points of view.

One special thing I took away from the barcamp was the idea of a Repair Cafe. This is a privately organized meetup of people to just repair broken everyday stuff and get some more lifetime out of it. It is some sort of counteraction against the creeping planned obsolescence of things. We were several people who were interested in that idea and it seems that Brigitte and I are currently the ones who are further driving the idea. Maybe there is the chance of a permanent recurring event where everyone helps everybody :)

Since Google Reader is discontinued by July 1st I've been looking for alternatives for some time now. I had a long look at Feedly but in the end didn't decide on it because it does not have a clean web interface but only works through native apps or browser plugins. So I chose to install Tiny Tiny RSS on my own. During installation I just hit a roadblock or two. In fact, my problems were that the minimum requirements for TT-RSS were PHP 5.3 and special server modes (e.g. no php_basedir/open_basedir restriction) while my hosting provider only offered PHP 5.2 with active open_basedir restriction. After trying to find an alternative to that (which wasn't successful) I decided to go the hard way and back-port and refactor Tiny Tiny RSS to work with my hosters restrictions. It took a few hours but finally I had a flawlessly running TT-RSS despite the settings of my hosting. I will post the changes here as soon as I come around to create a proper patchfile (maybe that will happen in the nearer future).

And finally last weekend I had the honor to be invited to my cousins wedding. It was a very nice and private wedding with (almost) only the closest relatives invited. Thanks for that and best wishes!