Repair on Michael’s Domain

Bio-Rad fixes our NGC

Wed, 20 Sep 2023 00:00:00 +0000

UPDATE (situation Dec. 21st, 2024)

We just survived our protein purification course (DPDR-305, see also my other blog posts related to teaching . After having done about 25 runs with the “repaired” Bio-Rad NGC, I sadly have to conclude that the most significant issue remains: that the FPLC becomes unresponsive to commands issued manually. Also, the randomness of these disconnects persisted. Only one student group had problems, but we had several incidents during that single day. That, sadly, concludes our short stint into Bio-Rad territory for protein purification. All of this indicates that any further investments into this device will be wasted time and money. We have neither too much time nor too much money. If Bio-Rad wants to do anything from their own initiative, I am happy to let them do whatever it takes to get the machine into a usable state, but we won’t actively pursue any further actions.The best way to keep your FPLC device in good shape is to have a maintenance contract. Although we have been able to get money from our university to buy a top-of-the-line FPLC twice in the last 30 years, getting money for a service contract is much more difficult. One of the many reasons is that most grant periods are shorter than service contracts, which only make sense if you make them over several years.

Review: Wenger Synergy rucksack after 5 years of daily use

Sat, 21 Jan 2023 00:00:00 +0000

I am a fan of rucksacks with many pockets. No wonder I like the Wenger Synergy , which has been on the market for over 10 years with only minor modifications. However, I had my fair share of quality issues with this model. Unlike my >40-year-old Swiss knife, this rucksack kept breaking within its warranty period or soon after. It was never a problem exchanging it when it broke within the warranty period, but I got fed up with the exchange hassle after doing it twice. The rucksack’s failing part was always the same: the seams of the shoulder straps started to open. I reported the issue directly to the producer, hoping they would change something to improve the shoulder straps. However, when also the third rucksack developed the same problem, I decided not to exchange it but to fix it. My fix is optically not very pleasing, but it has lasted long enough that I can report the second point of failure: the bottom pane. It ripped where the bottom piece contacts the backplane of the rucksack. I also repaired that one because I was interested in which part would fail next. The upside: these repairs were quick and easy, and they have already lasted for 4 months without any sign of failure due to the high-quality material. The zippers limit the ultimate lifetime of perhaps all rucksacksNow I know: the zippers are starting to have problems. I am surprised that the zippers are still sort of working. The zippers have been the Achilles heel with almost all of my other rucksacks. And unlike a shoulder strap, it takes quite an effort to fix (= exchange) a badly failing zipper. This rucksack is now five years old. I have been using it literally every single day. I cycle or run with it to work, and I do my shopping with it. I travel with it and take it to the summer cottage. Am I expecting too much of a ~100€ rucksack? Is five years’ lifetime the maximum I can get out of a rucksack these days? Sustainability is mostly just lip service, whatever the industry. I am determined to keep this rucksack for another 5 years, but exchanging the zippers will cost me at least 2 to 3 hours of work. As a quick fix, I used pliers to tighten the top and bottom wings of the metal slider (like in this youtube video ). That has been working, but according to my experience, this tightening needs to be repeated in increasingly shorter intervals, and finally, the metal will break. To avoid replacing the whole zipper, you can add buttons to create a new closure , which is perhaps less work if you are not very skillful at sewing.

Repairing our refrigerated centrifuge

Tue, 17 Mar 2020 00:00:00 +0000

Refrigerated tabletop centrifuges are quite expensive. Although discontinued, a refurbished Eppendorf 5415R (the model we use) still sells for $1-2K. The second of our two Eppendorf 5415R broke already more than a year ago and since then, we have been either centrifuging in the cold room or using the neighboring lab's cold fudge. But having two broken centrifuges of the same type, but different failure symptoms begged to assemble one functioning out of the remains.One of the centrifuge rotors was stuck (could not be turned even by hand) and the other fuge was giving sparks and smoke when starting a run. I had postponed this repair since I thought it might take much time. However, when I opened the first centrifuge, I immediately could identify the part that I needed to graft from the other fuge. The whole repair lasted less than one hour. There was a blown resistor next to the cooling fan, which was easily replaced with the part from the second fuge. You can see the broken brass-colored resistor (CGS HSA50 resistor, available from Amazon for$ 13) in the front of the picture left to the rotor.The failure of both centrifuges was apparently caused by liquid getting into the inner workings of the fuge. The rotor of the second centrifuge could not turn anymore because it was corroded from the salt and water. Also, the resistor had apparently been soaked (it is located immediately below the cooling grill on the top back of the fuge).The centrifuge works again including the cooling. I do not know for how long we will enjoy it, because it was already 2nd hand when we bought it in 2014. But even if it lasts only for another year, the repair was worth it.This type of repair might become easier in the future because if I am not mistaken, the EU is planning to mandate that manufacturers make service and repair manuals available to third party repair shops (this mandate exists already for car manufacturers to ensure that independent car repair shops can survivce).Depending on the coronavirus, I will perhaps get around repairing even more broken lab equipment. Next in the queue is the fraction collector of our old FPLC (GE Healthcare Äkta Explorer Frac-950).

Helkama quality woes

Sun, 25 Jan 2015 00:00:00 +0000

This post is a follow-up of my post from 2 years ago about my new bicycle, a Helkama Jääkäri . It had its fair share of problems, and even though the customer service was very responsive, the repetitive problems with its luggage carrier were too much for me. Last December, the third carrier broke. I had received also the this one as a free-of-charge replacement, but it is a nuisance when it breaks, even though replacing takes only about 10 minutes. It is not in very heavy use: the stuff I transport on it weighs about 2-3 kg, but apparently the welded/soldered connections are prone to fatigue breakage. Helkama knows that it has a quality problem with its carriers. When I asked for the second replacement carrier, the customer service told me, that they are trying to identify a suitable replacement for the subcontractor who makes these carriers. This time I thought to repair the carrier instead of asking for another replacement, which took less time and will probably last longer. I don’t know whether they have changed their component supplier. If my own repair breaks, I still have two old broken carriers I can repair, but most likely, my next bicycle is not going to be a Helkama .