I haven't got a clue, but I can tell you what I did.
The Olin DVR-130 DVD recorder that I bought 11 months ago died some weeks ago. I had had it open once (figuring out the chipset to find out how to region-free it), so no more warranty sticker. Well, not quite: Avery J5501 labels are perfect for that purpose, at 13x24mm. Openoffice didn't make too much of a mess printing them, the (really shoddy!) manufacturer's warranty repair shop didn't balk and so now I have a DVR-140 (next newer model, ok but no more vga output, sigh). I won't complain.
Next my trusty Mini-ITX box (bedroom audio, fanless, dervish-controlled) went wonky last week. First I suspected the cobbled-up 12V/5V power supply, which was labouring a tad (slightly underspec'd and thus hot). So I replaced that with yet another cobbled-up-but-beefier power supply, to no avail: I really should have disassembled the computer first.
Because had I started with that, I'd have seen the three dead 1500µF capacitors that caused the problems. Of course I have kilos of 1000 and 470µF caps at home, but not a single one of the required capacitance. Now what would MacGuyver do? Make his own electrolytic caps from tinfoil and toilet cleaner?
No idea, but a bit of simple electronics knowledge makes all that unnecessary. Caps in parallel means their values add up. The problems left were the lack of space on the motherboard, and the (lead-free?) solder that didn't want to release the deaders. Well, that's what brute force and ignorance are good for; a while later I had a replacement forest of caps, all leaning in different directions - but the computer works again :-)
Then came the water heater (in the last month I haven't had more than two days without digging into tool boxes). You might remember me hacking up a fried (sic!) coleman water heater a while ago. Well, it worked but it was hard to control the temperature: mostly too hot.
After looking quite some time at the slim pickings wrt. valves for cas camping gear (remember, left-hand threads on gas stuff) I finally found a coleman-cartridge-to-normal-gas-outlet converter with valve. (This is an item for truly stupid people: why would anybody waste money on throwaway coleman cartridges to power normal gas equipment that is meant to use refillable LPG containers?) Rob had given me a normal-gas-bottle-to-coleman hose, which also featured prominently in my plans.
So I cobbled up a fitting for the fitting, and the associated connections to the guts of the coleman (I really didn't want to bypass any of the nice safety features of the coleman, which made things a tad more complicated). Interestingly enough the innards of the coleman are all right-hand threaded brass, which made connecting air-hose fittings workable.
The wooden board holds the valve, epoxied into a slot to take the torque of screwing in the hose.
And it didn't work. At all. No fire, no heat, thus no hot water.
As it turns out I had forgotten that the coleman converter/valve is meant to be used on the high-pressure side of everything, before any regulator: so it has tiny holes and the gas flow of a gnat's fart. In my setup the pressure regulator is the first item, straight off the gas bottle.
Very annoying. Being me I thought "Well, it's fucked right now, might as well take drastic measures as it can't get any worse". And I did, and lo and behold everything got BETTER.
To fix the anemic gas flow I redrilled the inter-connections in the valve, all of them, and managed not to destroy the valviness in the process. Fortunately brass drills real easily. Blowing through the fitting feels fine now, reassembled everything, testfired it: perfect. Me happy.