ThinkPad X220 power connector repair

My ThinkPad X220 at some point started to complain that there was no power when I plugged in the DC power adaptor. After a while, the power would come and go (signalled by an ominous sound signal) as I moved around with the laptop in my lap, or even when I didn’t move at all. After a while, using the computer became an exercise in finding a «good» position for me and the laptop, and then not to move, at all.

My expectation was that this problem was due to the traditional broken solder joint with a power connector sitting directly on a fixed PCB. When I opened up the X220 however (see guide here, do clean out the fan while you are in there), I found that the X220 power connector was beautifully designed with the connector itself being clamped down and then connected to the motherboard via flexible wiring. I therefore concluded that the connector itself must somehow be bad, even though I was unable to confirm this visually or by measurement.

I ordered a new connector, and when it arrived I did the whole process again, fitting the new connector. That solved the problem… for about two hours. To my amazement, the exact same problem reappeared almost immediately after my «fix».

This called for another, more open-minded inspection of the problem. That is, I opened up the laptop once more, and tried to plug in the power connector while I could see what was happening. This revealed the actual problem:

I first clamp down the power connector, then try to insert the plug.

The connector simply isn’t fixed down properly, and moves away when you try to insert the plug. In other words, the connector itself is not the problem, rather there’s a mechanical problem with holding it in place.

It appears that the root problem is a tiny tab of metal on the laptop housing that is broken off. This tab would be so thin that I’m not even sure it was ever there, but this is the explanation that makes the most sense to me. In that case, even just a moderately excessive push on this connector would break off this tab, causing this issue. You can verify this problem without opening up the laptop simply by poking at the connector from the outside with a pen etc. to see if the connector disappears into the casing.

Having identified the problem, repairing it is in principle trivial. However in practice I found it not so easy. There’s no obvious way to weld or glue a new «tab» or back-stop back on. I ended up just stuffing the area with some material from earplugs, which leaves the connector flexible while still supporting a proper connection. This has worked well for me for a few weeks, although I suspect there are better solutions.

My solution to fix the loose power connector on the X220.

Washer dryer f13 error – a tale of diagnosis and repair

Our Hotpoint Ariston AQD1070D-69 washer dryer runs a heavy schedule in this house. The last few days was more noisy than usual, especially while the centrifuge was running. Then, the machine stopped with a massive display of blinking LEDs and a «f13 error» message. Panic ensued at family management, as the ever-flowing stream of laundry suddenly started to pile up. A swift repair was required.

This is the story of my repairing this machine, which might be useful for diagnosing a handful of related faults. Part numbers etc. mentioned will be specific to the AQD1070D-69, but the principles I’d guess applies to many if not most such washer dryers.

Searching «washer dryer error f13» immediately suggests a faulty temperature sensor in the hot air (dryer) channel. This channel runs on top of the drum, and is accessible by taking off the top cover (undo two screws at the rear). The aluminum channel consists of one upper and one lower part, screwed together with 6-7 torx screws (t20) and a gasket inbetween. Take off the top part of the channel, and this exposes the temperature sensor (part C00290251) which sits in front of the heating element, next to the air fan (the motor and fan is fixed to the top of the air channel).

There are some good videos available that shows how to access the sensor: here and here (although I guess you’ve already found those videos before finding this page).

Now unplug and take out the culprit, i.e. the temperature sensor. But is it really at fault? It is stamped 20K, meaning it’s nominally 20 KOhms at 20 degrees celcius, and less with higher temperatures. Measure its resistance (two small alligator clips worked well for me) at room temperature and in a cup of hot water. If the values are not reasonable, replace and reassemble. But mine seemed to report perfectly fine temperatures, so it was unlikely to be the real problem.

This means that for some reason the temperature in the hot air channel is outside the range of temperatures the brainbox expects. So either there is no heat (too cold) or there is no airflow (and so too hot). Which it is can be checked by running a washing cycle without the top cover and feel the temperature of the air channel when the f13 error comes on. (I didn’t do this at first.)

Next in line is the heating element. Measure the resistance over its two terminals. I don’t remember the exact value, but it should measure a handful of ohms. Also inspect the element visually that it’s not broken. You can also power up the heating element, if you’re comfortable with power electronics, but if resistance and visual inspection is OK, the heating element is likely fine, as mine was.

Now for the fan. At this point, the problem is likely to be too high temperature, which can only be from insufficient airflow in the channel. (Again, this can be verified by running a wash dry cycle.) Easiest check I believe is to hook it up to power and see if the fan runs. A wall plug connected to spade connectors is useful for this. As are the usual precautions with exposed power electrons. If the fan won’t run, it must be replaced. My fan ran fine.

Now, the fan moves air coming from the drum through a plastic channel running down behind the drum. If something blocks airflow, no air and so no heat will be moved. So we’ll remove and inspect this plastic channel. First, remove the lower part of the aluminum air channel, fixed with 4 or 5 larger torx screws (t27 I think). Also remove all the electronic connectors to the fan and heater element, and the two relevant water pipes. Take off the rear panel for access. The translucent plastic channel is fixed with large hose clams both on top (to the aluminum air channel) and bottom (to the drum). The upper hose clamp you don’t need to loosen for removal (the screw is difficult to access under the aluminum channel), but the lower hose clamp must be undone with a long screwdriver from above. It’s a tight fit, but the plastic channel can now be removed. Clean it out. Mine was dirty, but not overly so. Also, there is a green plastic filter where the plastic channel attaches to the drum. This might be where airflow is blocked. Take it out and clean it. Mine was quite dirty, but I wouldn’t think it should block airflow completely.

Now, reattach everything. Almost everything that should theoretically be able to cause the f13 error has been inspected and verified, so it is time to run a cycle and see if the problem persists. Well, in my case, it did persist. Quite peculiar.

When the f13 error now appeared, I did notice that indeed the aluminum air channel was extremely hot to the touch. That must mean that air is not moved properly. But I checked the fan already, and it ran fine!?

Running another dryer cycle, looking carefully at the fan motor spindle that is just visible, I could see that the fan was in fact not running. I pulled off the top of the air channel with the fan, so I could test-run in once more. And once more the fan ran just fine. This suggested something was hindering the fan from turning when it is mounted in position. The obvious suspect would be the heater element which is located right nest to the fan. But why would the heater element suddenly start touching and blocking the fan’s movement?

It was at this moment I connected the dots: The excessive noise we’d been hearing from the machine the last few days, was in fact the sound of the heater element being shaken and stirred inside the aluminum air channel. And sure enough, at closer inspection there was a small metal bracket broken off at the far end of the heater element, no longer holding it securely in place. Consequently, the heater made a loud noise when the machine was shaking from the drum running at high speed, and it also blocked the fan from running, causing zero airflow and so much too high temperature in the air channel (and no heat in the drum), triggering the f13 error.

In the picture above you can see the heater element, fixed with a new bracket (at the extreme right of the element) that I made from some sheet metal.

Now, reassemble everything, and enjoy a silent, error-free machine that dries your clothes somewhat more efficiently than before, due to the cleaned up air channels and filter.

ASUS tf201 tablet battery revival

We have a (by now) old ASUS Transformer Prime tf201 tablet that has been collecting dust for many months, because it wouldn’t charge. I figured I’d make an effort to revive it, and found it was impossible to turn it on, even when plugged in. Only occasionally I’d see a red battery symbol indicating low or bad battery. Also, the little LED in the power button would do triple blinks rather than stay solid red that would indicate it’s charging. No amount or combination of button-presses would convince the tablet to even attempt to boot up.

Some googling indicated that the triple blink of the LED means that the battery level is so low that the tablet considered it broken and would not charge it.

I assumed I would buy a new battery to replace the broken one, but thought I’d open up the tablet and have a look first. There are youtube videos showing how to open up the tablet, and picking out the battery was fairly easy.

I figured there would be no harm in making an attempt at reviving the battery. That is, there is of course potential harm in messing about with lithium batteries, so do proceed with caution. The battery unit consisted of two battery cells and a logic board. After pulling back some pieces of tape, two flat «wires» to each battery cell were exposed. A multimeter revealed a voltage of about 2.7 volts for each cell, which is certainly on the low side, but also not beyond rescue. The multimeter also identified the positive and negative terminals.

For the kids’ RC cars I have bought an «Imax B6» smart charger. It has modes for charging LiPo and NiCd batteries, among other technologies. I connected this charger to one of the battery cells, using this type of test probe connector:

Note I did this outside, wearing safety glasses and spider-alert-sense on «high».

Firing up (pun intended) the Imax B6 in LiPo mode, unfortunately it refused to try to charge the cell due to «too low voltage». Sigh. Well, a new quizzing of google revealed a trick to use the somewhat dumber NiCd mode to charge the LiPo cell up to a minimal voltage, before proceeding with a LiPo-mode charge. So I set the charger to NiCd and 0.5 amps, and let it run for an hour or two until a voltage of about 3.3 volts was reported, while making sure that the temperature of the cell was not going high, nothing was smoking or turning into a hitherto unknown lithium-based lifeform. Then, switching the Imax charger back to LiPo mode, I’d charge the cell for a few more hours up to some 3.8 volts, and repeat the whole process for the other cell.

After reassembling the tablet, lo and behold the thing booted up happily, reporting about 70% charged. To my considerable surprise, the battery has also been quite good ever since, holding its charge for a very reasonable amount of time. I’m tempted to say it’s good as new. I’m assuming this procedure might work for similar tablets and maybe also telephones.

Finally, when I booted up the tablet the first time, the root of the problem also revealed itself. Trying to charge the tablet by normal means, i.e. with the original charger (the tf201 requires a special 15 volt USB charger…) and cable proved to be very difficult. Turned out it was the USB cable itself that was half-broken, only making a good connection if held in a very carefully selected position. I’ve now bought a new cable, and everything works quite well. (To give you an idea, a good hour of youtube took about 10% battery.)

Again, to perform this procedure you should be very careful, and know your batteries, amps, volts, watts and wattnots.

Peugeot 807 front ball joints and wishbones replacement

When changing wheels recently from winter to summer tyres, I noticed some excessive play in the front wheels doing the 3-9’o clock test. I’d also noticed some clunky sounds from there when hitting small bumps in the road before, so there was no real surprise to find that both front wishbone ball joints were worn out.

The ball joints cannot be replaced separately on this car, you must replace the whole wishbone. I ordered a pair of new wishbones from ebay for about $80 each, which is about a sixth of a typical aftermarket part available locally, or at a guess a tenth of the OEM part from the dealership.

The procedure for the replacement is near identical for each side. The first order of business after raising the car and removing the wheel, is to undo and remove the pinch bolt in the steering knuckle that locks the upright bolt from the ball joint (15 and 16 mm sockets). Then undo the five bolts in the sub-frame that holds the wishbone, three of which are visible below. A breaker bar will be required (18 mm).

Now use a splitter fork on the ball joint to free the upright bolt from the steering knuckle. You’ll want to take care not to damage the heat-shield between the joint and the brake disc, on both sides I deformed it a bit so it made a grinding noise when the wheels turned and I had to bend it back out from the disc.

When the upright bolt is free, the whole wishbone should come out without too much trouble. You might need to lift up the stabilizer bar that sits right on top of the rear wishbone mount. You can use a lever on the bar directly, or lift the knuckle like I did here (I have a vague feeling I’m breaking some cardinal rule of wrenching by lifting the brake discs, but no harm seemed to be done).

When you get the old part out, verify that the new one is somewhat similar.

Also, have some fun seeing just how worn that old joint was.

Now, for installing the new part, I found it easiest to lift the steering knuckle (by the brake discs, as pictured above) a bit so as both to lift the stabilizer bar and the wheel knuckle to make space for the wishbone, and then position the wishbone mountings on the sub-frame. Then lower the steering knuckle (taking some care that the upright bolt doesn’t slash open the drive shaft gaiter) and fit the five bolts in the sub-frame loosely.

The problem at this point is to push the ball join (on the wishbone) down while positioning the steering knuckle to allow the upright bolt to enter the pinch hole.

This is a bit difficult because pushing the wishbone down requires some force. Also, if you are clumsy like me you will have pulled the driveshaft out of whatever sort of joint is hiding under that rubber gaiter, as you can see from the shapeless gaiter in the next picture, which also shows my solution to the problem.

The solution is to stick the splitting fork over the wishbone so that it extends forwards, and then use a long crowbar to get ample leverage over the wishbone. That is, the fork locks onto the wishbone, and the crowbar pushes down on the fork. I use a damp rag to get more friction between the splitting fork, wishbone and crowbar.

This way I can hold down the crowbar with my leg and control the height of the wishbone/ball joint while having both hands free to position the driveshaft, upright bolt and pinch hole correctly.

Once the upright bolt is seated in the pinch hole, fit the pinch bolt and tighten that and the five sub-frame bolts to 70 Nm. I’ve been told it’s a common problem that the upright bolt gets a bit of wiggle room and starts to grind out the pinch hole oval, requiring the whole steering knuckle to be replaced. So you might want to tighten the pinch bolt a bit extra.

On one side the drive shaft gaiter looked like this after I was done:

You can see the driveshaft has been pulled out too far. I was able to pull and twist the gaiter back into shape though.

Olabuss

Den gamle olabilen deltar i NGP 2014 for 5. gang. Den begynner å bli veldig knapp for to brødre, i tilegg til at den er, vel, ferdig. Planen var å lage en ny bil til storebror (og eventuelle kamerater). Planen var også å forsøke å få barna litt mer involvert i byggingen…

Jeg hadde flaks og fikk tak i to identiske trehjuls-tvillingvogner gitt bort på finn, av typen med et sentralt svingehjul foran, og to noe større hjul bak. Framhjulene er i praksis små sykkelhjul (samme type lager etc.), og bakhjulene er «plugg-inn»-hjul med integrerte kulelager, vesentlig bedre enn hjulene vi brukte før. Planen var å bruke bakstillingen nærmest uendret fra den ene barnevognen, og å bruke begge de to forhjulene foran.

Etter litt diskusjon med storebror bestemte vi å bygge rammen basert på to langsgående planker (vanlige impregnerte terrassebord). Etter litt fekting med vinkelsliperen kunne jeg enkelt skru bakstillingen fast på plankene:

 

Men som vanlig er det forstillingen som er den virkelige utfordringen. Svinghjulene har fordeler og ulemper. Fordelen er gode lagre og svingpunkt helt i senter av hjulet. Ulempen er først og fremst at vekten må hvile oppå hjulet, hvilket er forholdsvis høyt og litt problematisk både estetisk og i forhold til å ha et lavt tyngdepunkt. Det siste er litt viktig sikkerhetsmessig.

Første tilnærming var å ganske enkelt drille hull i plankene og sette inn hjulene:

 

Dette har både problemer med høyt tyngdepunkt og samtidig noe smal forstilling, en uheldig kombinasjon. Til og med storebror var uoppfordret bekymret for sikkerheten i en slik løsning.

Etter noe tankevirksomhet kom jeg på en løsning som adresserte begge problemene og i tillegg var litt kul: En tverrgående planke koplet til rammen med lange vognbolter og fjærer gir en bred og stabil forstilling, lavt tyngdepunkt pga. de lange boltene, og ikke minst fjæring. Med dette var de viktigste designelementene fastlagt, og jeg gikk til anskaffelse av: Kuleledd, gjengestang og øyeskrue (alt med M8-gjenger) samt passende vinkelbeslag til styremekanismen, samt de lengste vognboltene  jeg fant, med muttre og skiver (alt dette fra biltema og thaugland), og fra sykkelkontaineren på gjenbruksstasjonen fikk jeg plukke med meg et par hesteskobremser, diverse bremsevaiere, samt to spiralfjærer fra en sykkelgaffel.

Første versjon av den fjærende forstillingen var ganske enkelt å ta tverrplanken (anslagsvis 36×72 impregnert som jeg hadde liggende) og borre to hull til hjulene og to hull til vognboltene, og skru det sammen. Dette funket ok så lenge bilen sto i ro, men under kjøring ble det for mye vri-krefter på planken og dermed vognboltene. Tverrplanken ble derfor avstivet med to plankebiter (ca. 25 cm) av samme dimensjon som satt fast i rammen med gangjern. Dette funkerte utmerket.

På dette tidspunktet begynte tidsnøden før den store dagen 18. mai å gjøre seg gjeldende, så jeg har mindre fotodokumentasjon. I bildet nedenfor kan man se forstillingen ferdig, de to stagene sitter altså parallelt med de to lange plankene fra det første bildet, skrudd fast i den tverrgående planken med hjulene og montert med gangjern mot den tverrgående rammeplanken.

På bildet under kan man også se styremekanismen nesten ferdig: byggbeslagene er skrudd fast i hjulakslingene, og kuleleddene er skrudd fast ytterst i disse. Jeg tabbet meg først litt ut med plasseringen av kuleleddene, de må nemlig sitte nærmest mulig senteraksen (mao. eikene) på hjulene for at de to hjulene skal svinge noenlunde likt. Gjengestangen brukes som styrestag, og er koplet til rattpinnen med en øyeskrue der gjengestangen går gjennom øyet som så fikseres med en mutter (eller to) på hver side. Dette designet er gjenbrukt fra den gamle olabilen og fungerer godt.

 

Rattpinnen er ganske enkelt et av metallrørene som utgjorde rammen på den ene tvillingvognen, og som tilfeldigvis var passe lang og med en liten bøy i hver ende. «Dashbordet» som rattpinnen går gjennom og som man kan se over, er ganske enkelt fronten på tvillingvognen: Hullet rattpinnen går gjennom er opprinnelig der forhjulet var montert. Både form og funksjon på denne var perfekt til formålet.

På bildet over ser man også at jeg har montert bunn i bilen: Først sitter det en lengde av 36×72 på høykant under de lengste plankene (for å få lavere tyngdepunkt), og deretter er det skrudd 18mm kryssfinér opp mot dette. Enkelt og effektivt. (Kryssfinéren er forøvrig et annet finn-funn, jeg har nå nærmest «life-time supply» av store plater i halvgod kvalitet.)

Neste punkt var bremser. (Hvis bildene begynner å bli mørke, er det fordi de er tatt i mulm og mørke 17. mai.) Jeg ville ha bremser på begge bakhjul, og fordi begge hjulene hadde integrerte kulelager (altså ingen fast-roterende aksling) måtte bremseeffekten være mot selve hjulene. Jeg hadde heldigvis fått tak i hesteskobremser (samme type jeg brukte på den gamle olabilen), som har den store fordelen i forhold til V-bremser at de har festepunkt på utsiden av hjuldiameteren. Dermed kunne jeg lage noen enkle «vinger» i kryssfiner rett foran bakhjulene som bremsene skrus fast i:

 

Jeg brukte noe kryssfinér i ganske god kvalitet til dette, fordi det skal tåle litt krefter: Hjulene i fart vil trykke bremseklossene nedover med en viss kraft innbiller jeg meg.

Vel, bremseklosser er en ting, men de må kunne klemmes sammen også. Når vi nærmet oss et ensifret antall timer til løpsstart var det ikke helt klart for meg hvordan dette kunne ordnes. På den gamle olabilen brukte jeg et gangjern som bremsepedal, og dette funket ganske bra, så dette designet ble gjenbrukt:

 

Denne ble skrudd fast på passende sted ved førerplass. Så monterte jeg en bremsevaier på hver av de to bakbremsene, og strakk disse under bilen. Så lagde jeg til braketter for vaierne av kryssfinér som ble skrudd og limt fast under bilen, og til sist brukte jeg en bit patentbånd for å kople vaieren fra pedalen sammen med de to vaierne til bremsene. Patentbånd viste seg å være utmerket til formålet da den er solid, man kan lett lage til et stykke som er så langt man trenger, og det er lett å feste vaierne til den. Jeg får muligens dokumentere dette bedre senere.

På morgenen før løpet var det to ting som gjensto: Å lage en ryggstøtte bakerst på bilen (samt skru fast håndtaket fra tvillingvognen for enkel og behagelig dytting, ikke uvesentlig på løpsdagen), samt å lage et ratt. På et tidligere stadium hadde jeg en tanke om at jeg skulle lage et vakkert høyglanspolert kunstsykke i edeltre som ratt, men med minutter igjen til løpsstart så falt den planen ut. Jeg tok to plasthåndtak fra tvillingvognen (de man drar i for å folde den sammen) og skrudde fast i en firkantet bit kryssfinér, og det ble et ganske kult utseende ratt som det også var behagelig å holde i.

Off to the races!

Biltilsynet ga nybilen anmerkning for dårlig bremseeffekt, men dette tror jeg bunnet hovedsaklig i at jeg ikke hadde hatt tid til å stille dem inn. Løpet gikk utmerket, helt uten vesentlige tekniske problemer. Bortsett fra at den gamle bilen fikk en skrens i siste sving som skrelte gummien av det ene bakhjulet og totalt ødela det andre bakhjulet. Den må oppgraderes med nye lufthjul til neste år.

 

Peugeot 807 handbrake adjustment

The handbrake on our peugeot 807 (2004) has never been particularly great, but lately it’s been quite bad. Yesterday when parking on a hill I pulled the lever too far, and some of the surounding plastics was dislocated, to the extent that I couldn’t release the handbrake when I got home (luckily). Time to have a go.

I pulled off the plastics around the lever and got everything seated where it should be. However it was clear that the cable was too loose (hence why I pulled the lever too much), and something else was probably the root problem. Looking along the length of the cables from the lever to the rear wheels, it’s clear there’s just one adjustment point, where the single cable from the lever meets the two cables to the wheels. And that adjustment applies only to the left (rear) wheel. I jacked up the car, and as it turned out the handbrake was completely ineffective on that wheel, it was spinning freely even when the lever was fully engaged. Turning the aforementioned adjustment nut all the way in (tightening the cable) did not help at all. Apparently the handbrake has only been working on the right side wheel for some time.

I pulled off the left wheel to get a better view at the caliper. The handbrake lever (the little lever on the caliper, that is) did not disengage fully when the handbrake was off, apparently the cable was too tight. Thinking about it, this was probably the root cause: The handbrake is self-adjustable, which is why there’s (almost) no cable adjustment. However this self-adjustment requires that the handbrake (again, at the caliper end) is fully disengaged, as there is some sort of pumping action going on.

So, assuming the caliper is working properly, there are two things one needs take care of: The cable adjustment nut needs to bee loose enough to allow the (caliper) lever to fully disengage also on the left side, and each of the three cables need to have so little friction as to allow the calipers to pull back freely. Even with a loose adjustment my left caliper wasn’t really able to pull back completely, but enough that the handbrake started to operate reasonably well. I expect I’ll replace the rear left cable, as it’s not very expensive and it looked rather rusty.

Note that this self-adjusing mechanism means that testing the operation of the handbrake is not entirely straight-forward. You need to operate the car (engine running) and brakes and handbrake for a few minutes in order to make a proper asessment of the handbrakes’ performance.

Olabil forstilling 2014

 

Årets Nordberg Grand Prix nærmer seg med stormskritt, og det er på høy tid å få olabilen løpsklar. Bilen ble hentet fram fra vinteropplaget og inspisert, og det ble fort åpenbart at forstillinga trengte omfattende arbeid. Det var massiv slark og visse sentrale deler var i ferd med å gå helt i oppløsning.

 

I tillegg reddet jeg noen helt perfekte barnevognshjul som barnehagen var i ferd med å kaste under årets dugnad der. Disse hjulene er luftfylte, har bedre nav og låsemekanisme, og ikke minst har de integrerte kulelager. Perfekte som nye framhjul. Bakhjulene tror jeg er bra nok, så de lar jeg være. Men de nye hjulene er også litt større enn de gamle, og dermed må også front-støtfangeren fikses på sammen med forstillingen.

Jeg erstattet de ødelagte delene med frisk ved av litt større lengde, slik at det både ble mer stabilt for støtfangeren og bedre plass. Og vinklet for bedre aerodynamikk. I tillegg kortet jeg ned hjulfestene/akslingene slik at det ble minst mulig svingradius på hjulene.

 

Med tvinger og lister gjør man en «tohjulsmåling»:

 

En annen detalj som fikk en forbedring var bremsepedalen: Denne består av et gangjern og et vinkeljern. Problemet var at ved harde tråkk på pedalen ga gangjernet etter. En strategisk plassert trekloss sørger for en mer responsiv og solid brems:

 

Så her er bilen i all sin prakt, dog uten sete:

 

Forhåpentligvis er det slutt på regnværet nå, så vi kan få malt bilen i ny farge.

Vi rakk et par testturer, endog med et meget entusiastisk publikum i sjåførens gamle barnehage som ligger ved testløypa.

Muligens må vi øve litt på å begrense bruken av bremsepedalen, men vi fikk ihvertfall verifisert at bremsen er i stand til å låse bakhjulet, om enn bare et av dem.

 

 

Brake switch rebuild

My BMW K75 motorcycle’s front brake light switch (part 61311459569) was failing. I removed it from the bike, and confirmed by multimeter that the switch made no contact whether depressed or not. I tried to wiggle the contacts and spray it with some electronics cleaner, and although I got it working intermittently, I couldn’t really get it to work that way.

In the end, since a non-working switch is just worthless I determined to make a last ditch attempt: Dismantle the switch completely and then see if I could rebuild it. The problem was that the switch core was mostly set in plastic inside the brass casing, and I was unable to pull it out of there. So I took my propane torch and melted the plastic, leaving just the metal pieces (and the plastic push-rod, thankfully):

The way this works is that the brass ring goes onto the thinner end of the plastic pin, which then presses against the spring (the thicker end is the actual switch pin that is pressed against by the brake lever). The two metal contacts press against the brass ring from opposite sides, causing a closed electrical contact. When the pin is pressed, the thick part of the plastic pin takes on the position of the brass ring, breaking the circuit.

Now, the challenge is to put this toghether in a way that will hold up to some wear and tear.

First, I take a piece of plastic tube (a piece of wire insulation) that fits loosely around the spring (this is already in place in the picture above). A tiny piece of plastic (actually a piece of smaller diameter insulation) is superglued into one end to stop the spring from just going through the tube. Now, the two contacts can be superglued onto the tube:

In the picture below I’m holding all the pieces in the normally closed circuit position, and you can see both contacts touching the brass ring:

In the next picture the pin/button is pressed, and the circuit is broken (which would cause the brake lights to turn on):

At this point I take a small piece of epoxy putty and encase the contacts, tube, and spring, such that the whole assembly fits snugly into the brass housing:

I then fix the assembly to the housing with superglue (I tried hot-melt glue first, but that didn’t work). Doing this, it was critical to fix the assembly at the correct position such that the switch would be «normally closed» as it should be. Since you can’t look inside the switch to get the positioning correct, I keep the contacts hooked up to a multimeter while gluing. It’s a bit tricky…

Finally, wrap some electrical tape around the outer diameter of the switch housing and fill the gap between the tape and epoxy with black hot-melt glue:

Electromechanically this seems to work quite well. It remains to see if it’ll work on the bike and for how long, but I’m hopeful it’ll work for quite some time.

Peugeot 807 sliding door fix

The left electric sliding door on our peugeot 807 wouldn’t close. That is, it would almost close and then immediately open up again. We quickly figured out that the door would close properly if we gently pushed it shut at the right moment. A nuisance for the last few months.

A closer inspection and comparison to the non-broken door revealed that the problem was excess play at the top front door roller. Removing the vertical plastic trim on the door that covers the corresponding hinge immediately revealed the cause of the problem: The hinge bracket was loose due to a screw somehow having come undone. The bracket and screw is in the center of this picture:

I fastened the screw, and that was it, the door closed perfectly once again.

Sykkellakkering

Naboen har tre gutter litt eldre enn våre. Storebror arvet en av deres sykler, og denne har nå lillebror arvet igjen. Det som sikkert engang var en sprakende rødfarge har med årene falmet til noe som er farlig nær å kunne tolkes som en utilstrekkelig maskulin rosa.

Man kan jo ha en viss sympati med ønsket om en mer fancy sykkel nå som sesongen står for døren. Og siden boden fortsatt er full av spraylakk i det som liksom skulle være fargen til bilen vi ikke har lengre, var det lett å love en overhaling av sykkelfargen.

Jeg har aldri lakkert en sykkel før, men det ble fort klart for meg at man må demontere mer eller mindre hele sykkelen slik at man har kun rammen igjen til lakkering. Demonteringen gikk ganske greit (det viste seg etterhvert at kranken er festet med venstregjenger…), og til juniors store frustrasjon måtte vi så børste, pusse og vaske rammen før den faktisk kunne lakkeres.  Man kan nemlig ikke «lakkere bort» møkka som ligger overalt i kriker og kroker. Her bruker vi en roterende stålbørste på drillen:

Vi maskerte vekk hullene til styrelagre og kranklagre med maskeringstape. Så ble det ca. 10-15 runder med spraylakken fra forskjellige vinkler og med 10-15 minutter mellom hvert «strøk». En pappeske fungerte greit som «stativ» og lakkfanger. Det ble også 4-5 runder med klarlakk.

På bildet under er lakkeringen ferdig og jeg har såvidt begynt monteringen igjen med kranken.

En «fordel» ved å demontere hele sykkelen er at det er en utmerket anledning til å gå over alle deler og særlig lagre. Selve hjullagrene fettet vi opp i fjor, men nå kunne vi også rense og fette opp kulelagre i krank og styrelager. I tillegg hadde den mekanismen som låser fast selve styret til gaffelen rustet fast, så denne ble banket løs, renset og montert med litt kobberfett. Dermed er det mulig å stille styret i rett høyde også. Vaiere til bremser og gir kunne også smøres skikkelig i demontert tilstand.

Sist men ikke minst ble klistrelappen med storebrors navn og nummer fjernet. Sykkelen ble god som ny, tror jeg, selv om jeg er litt spent på hvordan lakken holder seg.