In message <1112231392.11253.43.camel at weka.localdomain> Jules Richardson <julesrichardsonuk at yahoo.co.uk> wrote: Heh. I've just spent the last hour looking for photos of some CDC machines to compare against. Nothing :-/ Going by the timeframe, I'd guess it was one of the later CDC Cyber machines, but the ?1,000,000 question is which one... Aaanyway, I've just bought a copy of "PET and the IEEE-488 interface" for a little under ?8 (due to arrive in a few days - mwahaha), not to mention the big box of surplus electronic bits that cost me ?55... Speaking of which.. has anyone got some spare 10-32 bolts and locking washers? I need at least ten of each. They seem to be like gold dust in the UK - all the suppliers I've tried only carry the metric M-series and imperial -BA series. Failing that, the contact details for someone in the UK that stocks 10-32 hardware would be most appreciated :) Later. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem at philpem.me.uk | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI ... Flash Gordon exposed himself to all sorts of danger.

In message <3.0.6.32.20050331171526.007a2980 at pop-server.cfl.rr.com> "Joe R." <rigdonj at cfl.rr.com> wrote: [ PET GPIB book ] About ?5 plus postage. Not a significant amount less than what I paid for the copy I've got on order. [ 10-32 bolts ] I need a minimum of 10x 10-32 UNF threaded bolts (aka "machine screws"), 3/8in length (or 1/2in) and locking washers. I have absolutely no idea what type of washer, but I'd guess it would be the variety with internal teeth. Basically I just need enough 10-32 bolts to hook five of these capacitors up. The problem being that 10-32 is a standard size in the USA, but apparently not in the UK. "I love industry standards. Everyone should have one." Thanks. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem at philpem.me.uk | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI ... Procrastination means never having to say you're sorry.

In message <3.0.6.32.20050331202354.00ab3460 at pop-server.cfl.rr.com> "Joe R." <rigdonj at cfl.rr.com> wrote: I've tracked down a source for the machine screws - Apex Fasteners in Slough (thanks to Jules Richardson for the lead). Now all I need to track down is some nickel sheet or ribbon, NI200 alloy, 0.002 to 0.005 inch thickness (0.05 to 0.125 mm). Before anyone asks, I'm trying to hack together something similar to the "hobby spot welder" on <http://www.hobbyspotwelders.com/>. I've got the computer-grade capacitors (five rather large Cornell Dubilier DCMX series 120,000uF 25V caps, for a total of 600,000uF with a tolerance of -10%/+75%) and just need the solder tags, screws and washers for them, and some electrodes. Shame it's so hard to find #4 copper wire (then again I'm probably not looking in the right place). The thickest I've found is 2.5mm solid core copper. "Sorry for destroying the electronics lab, Sir, it seemed like a good project at the time." Later. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem at philpem.me.uk | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI ... "I'll be back ;-)"

In message <16973.38648.101163.78847 at gargle.gargle.HOWL> Paul Koning <pkoning at equallogic.com> wrote: It's not supposed to be flexible - it's for the electrodes. Two pieces of #6 (5mm dia) copper wire, with one end ground down to a 1/32 rounded point. I can see two possibilities - either the 2.5mm wire will work fine, or it will blast itself apart when the capacitor array dumps 50-odd (or was it 70? need to crunch the numbers again) watt-seconds through it. Later. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem at philpem.me.uk | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI ... Error 216: Tagline out of paper

In message <5.1.0.14.2.20050401134451.0beaa1c0 at localhost> Tom Peters <tpeters at mixcom.com> wrote: [ battery tab welder ] Well, as far as I can tell, the core of the welder is a 680,000uF 25V capacitor (or a capacitor array), with some form of electronically actuated switch (transistor or relay basically) to connect and disconnect the power supply and a current-limited constant-voltage power supply. You also have an SCR (or a solid state relay, or even a normal mechanical relay if you can get one that's beefy enough) that switches the charger on and optionally a voltage monitor. I'd use an L200C regulator for the power supply - it can handle 1.5A and has current limiting and voltage regulation built in. The HS300A2 welder seems to take 24V on the input, and has a power output of around 110 watt-seconds. That seems to be easily reproducible - the only really expensive parts are going to be the capacitors (I got mine from Mainline Surplus Sales - <www.mainlinegroup.co.uk>) and the SCR or SSR. I'm still trying to track down a nice, powerful SCR that can handle 1000 amps for about 10mS. As far as logic goes, all you really need to do is disconnect the power supply when the trigger button is pressed. A simple transistor inverter circuit should be sufficient: Trigger sw. | SCR Power --------------------------- 0 | 0 1 1 | 1 0 That just leaves connectors - I don't recognise the connectors HSW used, but I'd guess that they're standard medium-current power connectors. If you really felt like skimping on cost, you could probably get a smaller capacitor. I've only got one cap wired up at the moment and it's still capable of welding two pieces of thin tinned copper wire together. I wonder how well it would work for making Cu/CuNi thermocouples... The only thing I really need now is nickel foil (sheet, shim stock, whatever the proper name is), about 0.003" thick. McMaster-Carr sell it as order code 9707K33 - that's the standard NI200 alloy stuff used for battery tags. It's $62 for a 6" by 50" length, assuming the website is accurate. I'm still trying to track down a supplier in the UK. I found one that seemed to think that ?50 for a 10cm square piece of 200 alloy nickel was a reasonable price. $60 seems OK, but the shipping would probably be pretty expensive :-/ Later. -- Phil. | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB, philpem at philpem.me.uk | ViewFinder, 10BaseT Ethernet, 2-slice, http://www.philpem.me.uk/ | 48xCD, ARCINv6c IDE, SCSI ... If it wasn't for C, we would be using BASI, PASAL and OBOL!

On Mon, 2005-04-04 at 22:11 -0500, John C. Ellingboe wrote: I imagine that Phil's enjoying trying to do this himself - plus I can't see anywhere in that website where it says that they'll ship across the pond! :-)

On Mar 31, 2005 5:15 PM, Joe R. <rigdonj at cfl.rr.com> wrote: Excellent. A good book if one wants to understand the GPIB at the handshake level (or the 6502-code level). It's obviously PET oriented, so the character-level detail won't directly apply to understanding how HP devices work, but it does do a good job of illustrated how talkers, listeners, secondary addresses, etc., all work. -ethan