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Fusor Progress, Luke Harrill

Posted: Thu Jun 21, 2018 6:17 pm
by Luke Harrill
I've almost got all the parts for my vacuum chamber and gas system. (The missing parts are marked with index cards.) I also have a Welch 1402, a Televac TC gauge controller, 2 large 75k ohm power resistors, a variac, a 50kv probe w/ meter, and a rectified xrt w/ cables.

I am still working on the following: another TC gauge controller (or maybe an ion gauge setup), grid/stalk material, current metering system, vacuum oils, and neutron metering equipment.

I can initially use activation for neutron detection, and the rest of it is providing that my current equipment doesn't need any repair.

-Luke Harrill

Re: Fusor Progress, Luke Harrill

Posted: Fri Jun 22, 2018 12:26 pm
by Dennis P Brown
Activation is not generally a good approach for a first time fusor attempt. The very least you will need a good x-ray transformer capable of creating the high rate of neutrons - that is, a high voltage and current device (see FAQ's on the exact levels most use for activation.) Considering the money you already have spent, maybe it would be better to consider the standard method and get a turnkey system. Richard has discussed this very issue of beginners trying activation detection a few times as well.

Re: Fusor Progress, Luke Harrill

Posted: Mon Dec 31, 2018 1:12 am
by Luke Harrill
It has been a while since I last updated, but I've been making a lot of progress (and messes).

I was cleaning my diff pump and managed to break one of the wires off the cartridge... On the bright side, I managed to find a mass spec at a local auction for $146. Inside was a Leybold turbovac 50 and controller!!

I have also gotten around to getting a belt and oil for the Welch 1402. I will soon be testing it, but I fear I may need to replace the mech seal due to a few drops of oil gathering on it while in storage.

Also, my neutron moderator is filled with paraffin wax! I had to keep topping it off while it cooled, as the wax expands while hot. I just hope there aren't any tiny air pockets inside of it. (I tried to paint it too, but it didn't stick well... It kind of looks like a giant prozac)

-Luke Harrill

Re: Fusor Progress, Luke Harrill

Posted: Mon Dec 31, 2018 3:48 am
by Richard Hull
Good work so far Luke. I see my fabulous old 55 tube counter there. I miss it. It was a love's labor restoring it. I also see some of my NIM modules, but it looks like you have made up a nice amplified speaker NIM module there. Did you use an old gutted NIM module or did you just craft a 2 space plate to fit the NIM rack and put the speaker, amp and control on the back of the plate? Either way, it looks nice.

I hope you and your dad can make it back to HEAS next year. Kit and I enjoyed having you guys dine with us at the Texas Road House.

Richard Hull

Re: Fusor Progress, Luke Harrill

Posted: Tue Jan 01, 2019 1:25 am
by Luke Harrill
Yes, Richard, your tube counter is one of my favorites. I'm pleased that I can put it to use once again.

The speaker module was a HEAS find as well, but it is on the repair list. (It will be fixed as soon as I can fix the power supply board on my oscilloscope.) I would like to attach a photo of the circuit for you to see, but I am getting an error saying that the quota has been reached? I tried with several file sizes. (Edit: fixed)

-Luke Harrill

Re: Fusor Progress, Luke Harrill

Posted: Tue Jan 01, 2019 8:28 pm
by Dennis P Brown
Great find on the turbo! I did a similar thing for mine (a lower price but I was really lucky there.) I keep saying to people that finding great deals is possible but one needs to look and know what they are looking for/at.

Re: Fusor Progress, Luke Harrill

Posted: Tue Jan 01, 2019 8:49 pm
by Richard Hull
Wow! That homemade audio NIM module is ancient! There are a number of give-aways in the view you supplied. The board's hole size and spacing are from the 50's-70's. The large TO-3 transistor feeding an audio transformer is no longer needed to drive such a tiny speaker. The single IC amp chip is of a first generation type needing a lot of "off-chip" components. A very amateur effort but sufficient for the time.

I built my own NIM speaker module in the late 90's and used the little 8 pin LM386 audio amp ( 80 cents) and two or three additional components to drive the speaker directly.

Richard Hull

Re: Fusor Progress, Luke Harrill

Posted: Tue Jan 01, 2019 11:14 pm
by Bob Reite
I love old electronics like that. Nostalgia of the stuff I built during my high school days. You can actually see the parts without having to use a magnifier. Needless to say, my new designs are more compact, but I still use through hole components unless the device I need is only available in SMT. I did bite the bullet and get SMT rework equipment for doing repairs on equipment that's too expensive to throw away or send back for factory repair.

Re: Fusor Progress, Luke Harrill

Posted: Wed Jan 02, 2019 3:04 am
by Luke Harrill
Thanks, Dennis!

Richard, you are right on spot with the dates, as there are two stickers from '68 and '70 on it! You would have also noted the 2 sprague "atom" caps, but I had already replaced them when I took the photo (and cleaned the pot too). I have found 2 solder points that broke loose when I touched them, so I may have to end up re-working it a little. It is certainly interesting.

That's one of the reasons that I love older electronics so much. They are beautiful to look at and easy to repair!

-Luke Harrill

Re: Fusor Progress, Luke Harrill

Posted: Wed Jan 02, 2019 5:04 am
by Richard Hull
All my projects since the late 70's are proven on a standard .10 spacing proto-board grouping and then actual component placement of a working model is mounted on a pad-per-hole .10 G10 PC board. If it is a one-off project, that finished board serves. If for a salable item, I use Express.PCB to make up my PC boards that I design and layout with their free software.

Back in the 50's I used those old clunky boards which accepted Vector push-in terminals, if you wanted it pretty. Otherwise, I just went with the rat's nest on the board as seen in Luke's image. Signal tracing on these boards was easy....No close quarter parts.

Richard Hull