Friday, 8 December 2017

Miele Induction Hob Problem

Miele Induction Hob Problem

We've had a Miele KM5731 for nine years or so, it took a while for me to fit it after we bought it, so it's probably been installed for more like 8 years. Anyway, a few days ago it started to give an error code of FE32.This is the hob, it has four induction coils and some touch buttons.

The error code appears in the power level displays:

Once the error code appears the hob is unusable. The instruction manual isn't much help, it says turn it off and on again. Well, that might work, but it's got progressively harder to conjure away over the past few days. A search on the internet resulted in many useless sites and one very useful Dutch site. From that site it transpires that there are a couple of capacitors on the power PCB that can pop and lead to this error code. I took the hob apart and had a look and indeed there were two capacitors with bulging tops.

They are both 470uF 25V electrolytics, this one has split and opened:

This one has just expanded on top:

I ordered some new high quality capacitors to replace these two and also some to replace the other electrolytics on the PCB. These arrived today and I have replaced the capacitors. So far no sign of FE32, but we'll have to see over the long term whether it's fixed or not.

Interestingly the decent quality (Panasonic) capacitors I ordered were identical to the ones fitted, except for the date code, apart from the two that had popped. So it looks like maybe there was a supplier issue with those two.

Thursday, 30 November 2017

Remade Bag

I was asked to remake a bag a while back. The original was made of thin nylon type material.

The material for remaking the bag is on the left. It's an old curtain and is considerable thicker than the original. I took the handle off and unpicked the bag to make a pattern. Then stitched it all up again.

The bag just fitted in the material available, so I'm hoping it's big enough. I think I've made it a little bigger than the original. We'll see.

Tuesday, 28 November 2017


A while ago we bought a changing bag for the ongoing project. It was pretty cheap on ebay as it had a broken zip. At the price it was going for, about a tenth of retial price, it was worth it. It looked like the zip was fixable as it had just pulled away from the bag in one place.

After a quick fix we started using the bag, and found that the zip had pulled away as it had failed. the zip wasn't very smooth in that area and needed to be pulled harder in that area, which led to a failure.

Plan B was a new zip. Off to ebay again and a few quid later we have a new zip. Yesterday I finally had a slot available to get the sewing machine out.

Removal of old zip:

The new zip was then sewn into the bag:

The internal piping was re-attached which tidies up the zip edges:

Bag now usable. We just have to see how long this fix lasts...

Friday, 24 November 2017

Broken Keyboard

To control the Maslow I use a wireless keyboard, which is very useful as I can operate the Maslow at close quarters rather than being tethered by a keyboard cable to the control computer. Unfortunately I was using it recently and dropped it on the floor. This has happened beofre but this time when I picked it up and tried to use it, it wasn't working. It looked like the supply wasn't connected any more.

I took the keyboard apart and there was a dodgy looking inductor from the batteries to the PCB. I checkd with a multimeter and it was open circuit. I replaced it with a wire and checked. The keyboard started up and the keys worked, but the trackball didn't work and the low battery LED filckered. So it looks like the inductor is necessary to smooth out the supply voltage or help with transients. I didn't have any inductors, at least 100uH ones.
I chipped the paint off the inductor and found a ferrite core. The problem was the connection to the windings. The core seemed sound so I got some wire (the same wire I used when connecting the eMMC chip to the USB adapter) and rewound the inductor:

This fixed the keyboard, the trackball now works well.

Saturday, 28 October 2017

More Maslow

More Maslow

I tried a test cut on the Maslow recently and had a problem. The plywood circles I cut out before for the filament reel were cut fine. The new test part was a chair leg cut from scaffolding board. As the board is 36mm thick many passes are required to cut the part as I didn't fancy a full depth cut. The problem showed itself as a dropped USB connection. This stops the cut and I had to re power the arduino to get a link back. After some experimentation it looked like the router is generating noise that kills the USB connection. It also seem to very comprehensively kill the WiFi too.

I tried a main filter on the Maslow and computer but that didn't work. Trying to use an old-ish laptop also didn't work as the ubuntu was too old for the software, so that was out. next stop was the purchase of a proper line filter.

This allowed me to cut the entire part (which took about an hour) without a dropped USB connection. I'm pretty happy that this has gone a long way towards fixing the problem, this part took a long while to cut and is one of the biggest ones in the chairs. I may want to cut an entire kit of parts in one go, which would be two of these and some other parts, but I may be able to do that with a deeper cut (especially if I buy a new cutter).

The  sled had to have outriggers added so that it could be stable across the entire board. This worked pretty well too. You can just see them in this photo:

I'm not sure what I'll do if I try to cut from full width boards, this was a smaller board cut from a larger one. I may need outriggers over the top of the sled, or maybe the wider board won't require outriggers on the sled. We'll see.

Wednesday, 4 October 2017

Maslow Update

Maslow Update

The Maslow is now together:

This morning I moved the motors forwards so that the chains are more parallel to the work surface. Hopefully this will stop the chains jumping on the sprockets when I start cutting thicker material.

The router I am using is quite top heavy and this causes the sled to tend to tip backwards, especially if the router bit it out from the work surface. at the moment I'm putting a rod of steel on the top of the sled as a sort of counter weight. It works, so I'm happy at the moment.

I have made the first 'thing' using the machine:

Well, OK, it's the parts for a thing, not a thing, but this is the sort of thing the Maslow was for. Big plywood things. At first anyway, maybe big scaffolding board things later. These parts are going to be a filament reel for the 3D printers. I've made them manually before and this was way quicker. And I can do something else while the parts are cut out.

The calibration was a bit out before I moved the motors. I'll have to re-calibrate now the motors have moved, but hopefully I can get the calibration back to something as good as I had before. Those discs I made are slightly oval, but I'm hopng I'll be able to manually adjust that out on the next calibration.

The Z axis mount works remarkably well, considering the wood isn't actually attached to anything, it's just wedged in there.

I may have a go at 3D printing a replacement for the wooden version, but this works, so I'm in no hurry.

Tuesday, 26 September 2017

Prototype X-Y Table

 The new microscope came with a nice XY stage, but the slide holder was missing. I made one from a cheap XY table. The XY stage is manual, which is fine for adhoc looking at dies, but for photographing dies and then stitching photos there's a lot of photos. It's tedious doing it manually. So I prototyped an XY table from DVD drive stepper motor assemblies.

I had an arduino and two stepper drivers, so connected it all up;
The result is here, the two stepper drivers are being driven with the same signals.

And another view.

I'll have to make a stage block with a dovetail to mount this on the microscope. I may also remove material from the top table as it could do with being a bit lighter.