Posted in Floppy disc R/W project on Sep 29th, 2009 No Comments »
It seems this project has consisted of one cockup after another… – First off, I managed to swap the A and B buses on the level translator chips. The “A” bus goes to the disc drive, the “B” bus goes to the FPGA board. Get it the wrong way round, and the FPGA gets zapped [...]
Posted in Electronics on Aug 10th, 2009 3 Comments »
Once again, I’ve started an expensive project. A few days ago, I was building up an LCD controller board, which involved soldering down a lot of small parts. Worst of all were the flatcable connectors for the LCD — these are made out of a plastic that seems to melt at about 100 Celsius. Not [...]
Posted in Electronics on Jun 4th, 2009 No Comments »
Hmm, seems I’m blogging more than usual. Is that a good thing or a bad thing? I’m really not sure… Well anyway, I’ve spent the best part of two days building up a GPS receiver. It’s based on a FasTrax iTrax321 “receiver on a chip” (actually a SiRFStar III chip and support components mounted on [...]
Posted in Repair Tips on Mar 10th, 2009 5 Comments »
*Device:* Viewsonic VX922 TFT monitor *Fault:* Power light blinks green “long on, short off”. Some signs of backlight activity, but display otherwise black. *Cause:* Defective “Capxon” electrolytic capacitors on AC power board. Possible issues with defective “Teapo” electrolytic capacitors on the controller board. *Solution:* Replace all electrolytic capacitors on the power supply board with suitable [...]
Posted in Computers, Electronics, Floppy disc R/W project on Oct 13th, 2008 No Comments »
A few of you might be aware of my pet project — a floppy disc reader/writer that operates at an insanely low level (it operates on individual magnetic flux transitions). The advantage of this thing being that it’ll be able to read (and write!) just about any disc format that can be read in a [...]
Posted in Electronics on Sep 13th, 2008 1 Comment »
I think I’m on a “make it smaller” bent again. I’ve ended up building a laser tachometer to assist in testing the motor speed controller code (which is going to end up using a PID loop for speed control, more later). After I finished it, I realised that I’d ended up designing what effectively amounted [...]
Posted in Electronics on Sep 2nd, 2008 No Comments »
If you’re just here for the answer to the question “how fast does the Ptouch motor need to run”, the answer is 3000RPM. Ish. I’ve confirmed this using two different measuring methods — measuring the timing between noise spikes on the motor’s power lines, and the old reflective-tape-and-laser trick. I didn’t use the motor inside [...]
Posted in Electronics on Aug 30th, 2008 No Comments »
Well, yesterday I nipped down to Maplins and bought myself a Brother PT-1010 label printer, as an upgrade for the PT-1000 I’ve been using for the past few months. This was mainly down to the fact that the ’1000 was nearly useless for labelling component boxes — mine would never print the micro (mu) symbol, [...]
Posted in Computers, Electronics on May 11th, 2008 2 Comments »
Why can’t anything be as easy as it looks? I’ve spent the past two days trying to get my Tek TDS2024B to talk to a Linux box via a homebrew USB-TMC driver library. Based on the USB-TMC spec, I’m doing everything by the book — and in fact, I can get the scope to respond [...]
Posted in Electronics on Jan 2nd, 2008 2 Comments »
… Or more influenced by xkcd comics maybe. Picture this: Big sign. Two red seven-segment displays, incrementing daily, and a big red button at the bottom. Text: “n DAYS SINCE SOMEONE WONDERED WHAT THE BIG RED BUTTON DID.” Yep. Boring. Simple minds and all that.
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