Craig Sawyers

Semis just arrived, with the only waited for item being the 2SC3381GR. Luckily judging by Inu's post I've got 2SK246GR and not BL. At least I can stuff every semi not heasink mounted (apart from the '3381s) now.

That got me thinking. Doing some calculations, the LED's are all operating at reasonably low currents - either 1mA or around 0.5mA. So they will only light dimly, and from the datasheet develop 1.8V. I'd start looking around D24, Q30 and Q31. These are current sources for Q4, Q5 and provide the current through the batteries. This current should be 1.8 - Vbe = 1.2V across a 240 ohm emitter resistor - or 5mA. In addition if something is screwy with the circuit around D1, the biassing of Q4 and Q5 will be up the chute. One or both of those could well put the battery into an inappropriate regime - if it is expecting 5mA and is getting significantly less for example (I haven't figured the circuit for the battery yet). Er good luck - I'll be in the same place as you in around a month's time.

Looks awesome! Turning on power for the first time is a really sweaty palm moment. Always. The only insurance is to check, check - have a cup of coffee and go for a walk then check again.

Stick with it - it grows on you as you get to know the characters. The musical numbers are not quite up to Family Guy standard (who can forget the FCC number), but pretty good nontheless.

Mongrels. Late night BBC adult puppet show about a group of animals (fox, pigeon, dog, cat etc). Voiced by a selection of comedians - hilarious. Currently at episode 3.

Luther = superb. Shaky start while it found its feet - but excellent later in the series.

Finished the power umbilicals today (getting everything prepped for the arrival of casework in due course). Forgot how fiddly it was to wire up Amphenol mil spec connectors. I guess it took an hour or two to cut the wires precisely to length, twist the heater wires (to reduce hum radiation), pull though mesh sleeve and adhesive lined heatshrink the ends. Then cutting up neoprene sleeving to the correct length (around half an inch). All told maybe 4-6 hours for the pair. After soldering one end I did a pin to pin check to eliminate wiring errors (one found and corrected), and a leakage check to ensure that there were no faults in the ubmilical or the connector. Used an AVO mega-ohm meter, which has a switchable voltage up to 1kV and measures up to 10Tera-ohms (10^13 ohms). Well the leakage of my test setup was 10^11 ohms, so all tests were relative to that (to get much further the whole set up has to be on a teflon sheet). Every pin was checked to every pin, and it was all well over 10^11 ohms at 1kV for every wire to every wire - which is an excellent result. Very happy with that. I made them up at 4 feet at KG's suggestion - that allows the units *not* to be stacked, so helping heat build up.

I didn't watch Life on Mars, but entirely intend to. I only watched the last season of Ashes to Ashes and it was unremittingly excellent, with a really stunning final episode. So let me see - I need to watch two seasons of Mars and two of Ashes - but it is going to be so worth it judging by season 3 of Ashes.

It is the winding connected to the output marked "60V power supply" - that adds -60V to -500 to make -560, and the one marked "300V power supply, that adds 300V to the -560V supply to make -260V. And yes - winding wire is supposed to hold off 500V - but I wouldn't like to rely on it. It might be OK at T=0, but after repeated thermal cycles I would not have confidence that it would hold up long term. It is one of the reasons that transformers with an interwinding screen are often unreliable - the devil is in the detail.

I though - nah, that can't be right - the difference must be significant. I remembered Leslie's Cube from schooldays and foggily recalled a much greater effect. But then I found and scanned "An experimental inquiry into the nature and propagation of heat", By Sir John Leslie, 1804 (Readable on Google books) and noticed that the basic experiment only measures radiant effects - not convective ones. So the experiment is entirely relevant for space based thermal radiators (which would have astonished Leslie), but not ones in air. But then I found the comment relating to normal heatsinks: "Under natural convection conditions, the performance of a heatsink with a black surface will be 6% to 8% better than that with a plain or bright surface. However, this differential disappears under forced air conditions." Significantly less than I had intuitively expected - but consistent with the primary cooling effect being convection. The above comment was on Basic Theory , which seems to be a distillation of heatsink info from several sources.

One additional thing that is worth mentioning to a transformer manufacturer is that some of the windings float at high DC. Specifically the heater windings to the EL34's (-500V), and two of the HT transformer windings are referenced to -560V or -500V. So those windings in particular need an insulation barrier - just overlaying one secondary over another probably won't work (it *should* in principle, because winding wire is good for more than that - but not if any insulation is compromised through nicks during winding, or just thinned because of winding pressure).

Sounds amazing Doug! But beware head brewer syndrome. Mrs S is an accountant, but way back when she was an audit junior she was on the stock check team of a local brewery. She was warned not to approach the head brewer until the afternoon until he had done a good session of "sampling" and was not suffering from the after effects of the previous day's sampling.

FWIW my total Mouser bill was

Oh bloody well done! Nice one.

Looks like an interesting outfit - good luck!

Have they seen the 80's Thomas the Tank Engine TV series with Ringo Starr doing the voice over? Allegedly Starr was using doing the series as part of rehab coming off the booze. Anyway, the early series with Starr were iconic and excellent - my kids were of that pre-school and early school age when it was first aired, and I had great fun watching it with them.

Well, I sure sweated doing the precise same thing in my driveway. Got to a sweltering - well for the UK sweltering - 30C (86F). Hasn't rained for what seems months. English Lake District, which was at the receiving end of near biblical flooding in October 09, is now in an official drought with hosepipe use banned.

New series of top gear. Usual mixture of madness, capped off by May driving up an Icelandic volcano (the same one that blew its head and disrupted air travel). Tyres eventually burst into flames at which point he retreated.

Because I have little or no interest in the sport, I valeted our older car as a graduation present for our daughter. But I could tell the inevitible was happening by a stereo groan of despair coming though open windows along our road as each goal went in against England. Now we'll have to get through days of navel gazing by the pundits. There will be no repite....

The series got better as it went along, with the brilliant one liner to finish off "NOW what do we do?". Can't wait until the next series.

Jeez - if that birthday party has been going on for 3 years, it is no wonder the beer has expired

This has just got to be the wrong list for discussing running shoes - but the theory behind these is that since 50% of the bones in the human body are in the feet, they are there for a purpose. The whole foot is a very advanced shock absorbing system, intended to be in touch with what it is running on. The arch is part of that - ideally with the foot striking on the outer edge of the foot, rolling inwards towards the arch (which flexes downwards as it takes the load), the heel touches the ground very lightly, and the the calf pushes you off again. And yes - track racing flats (apart from the spikes) are not dissimilar in the correct lack of support of five-fingers.

Another UK source of UNC fixings, including black, in various headstyles and 1/8" length increments http://www.modelfixings.com/

Scratch the 10mm comment - the board height is fixed by the heatsink bracket position.

I wondered what the second coupling was - that is a really neat design, and keeps visible shaft grub screws completely out of the equation! With the fancy Alps, you have to go *up* from 1/4" to 8mm, whereas with the DACT you need to go "down* to 6mm.