LGK-7630

I started working with lasers in 2003 when I bought the above Siemens LGK-7630 HeNe laser off eBay for like $15.00. It was lots of fun; rated at 6.0mw; manufactured in march of 1984, and tested 6.4mw (according to a sticker) in 1986; apparently removed from an old Xerox product of some sort.

Shortly after getting my second laser, the Argon Ion one, the power supply on the Helium-Neon failed catastrophically. This isn’t such a surprise for a $15.00 laser, but I couldn’t find a suitable replacement at a reasonable cost for a long time. Having the JDSU 2214 around made it even less of a priority.

Fast forward to 2006; development on LaserLine and the galvanometers is getting serious, so I need an easy to operate beam that I can switch on and off with no fuss so I can focus on development of the scanning hardware and software. No maintenance; instant on, quiet operation. Perfect.

Power Supply

Meredith Instruments (via eBay) happened to have a Melles Griot 05-LPM-948-065 Power Supply at just the right price. It does somewhere between 1.85 and 2.45 KV at 6.5ma; quite reasonable for the 15″ LGK-7630 tube (well, the enclosure is 15″, I’m guessing the tube is 13″ or 14″).

A quick trip to Fry’s provided me with some parts for the enclosure; other parts were found in my basement. Plenty of Dremel work was required for the IEC power plug and 1A breaker, but they look nice. Now I just need a source for a key switch, because it is a class IIIb laser, being above 5mw. Black paint should really make it look better too.

Beam Profile

The beam profile on the HeNe is so much rounder and consistent than any laser pointer I’ve ever used. (The dimmer 2nd beam in the top picture is laser pointer to which I was comparing beam profiles.) The picture below illustrates the quality Gaussian profile, but also illustrates the noise around the outside. I’m thinking much of it can be attributed to a dirty external surface of the OC. Pretty good for 22 years though…

I’m really excited.

Dear Joseph Hagedorn,

Congratulations! The Apple Developer Connection is pleased to award you a WWDC 2006 Student Scholarship. This exclusive Scholarship Program will kick off on Sunday, August 6 with a full day of presentations and hands-on sessions designed specifically for student developers…

This means I’ll be in San Francisco from August 5th or 6th for at least a week. Its been so long since I’ve traveled, now I’ve got an awesome trip to go on. Excellent.

The lack of access to a cost effective machining solution has prompted the construction of Acrylic parts for the frame of the galvanometers. Hopefully these pieces will be replaced by aluminum ones, but for now I’ll at least have something to work with that is more substantial than wood. Everything is cut but is still in need of drilling and tapping. I still haven’t been able to find an appropriate tap handle for the M2 size tap or 2mm size set-screw collars (well, in quantities less than 100). I’ll need to find sources for both of these items before much more work will be completed.

After three months of waiting, I finally received Ungar part # 9037, a Tip Retainer for my (somewhat) vintage 9911AS soldering iron. It doesn’t fit. Action-Electronics is going to get a call tomorrow, then I’m probably going to start honing my metalworking skills to modify this part… or something…

I still hope for a positive end to the week with the arrival of a HeNe Laser Power Supply for that old 6.5mw tube I’ve got in the basement…

For almost 3 years now I have dealt with a horrible buzzing noise emanating from the external speakers connected to my PowerBook when it was plugged in to things on my desk. At some point I discovered it was linked to having my 17″ Apple Studio Display plugged in, but leaving it disconnected kind of defeats the purpose, so I didn’t track the problem any further. So the magic is this; turn the brightness slider all the way up in the Displays control panel, and no more buzzing! It turns out that it is only the dimming of the backlight that introduces this noise over the ground plane. I couldn’t believe I didn’t figure this out earlier! Finally I may begin enjoying my Fostex PM 0.5’s again. Sweet.

I can’t say I love DirecTV, but TiVo just made it a lot more bearable. I still blame DirecTV for the slow performance of the grid guide on our HR10-250 recorder, but other than that, it’s a solid product, especially with the dual tuners.

DirecTV is also at fault for the silly old software version running on the thing, presumably to make their other boxes not look so lame compared to TiVo. The new version is so fast and convenient with folders.. and our 4XX hours of recording capability gest slightly out of hand… but I expect no upgrades. I like the HR10-250 over prospective future products because it tunes HD over the air, allowing us to avoid paying DirecTV for a LOWER QUALITY version of the same broadcast I pick up with our 20 yr old aerial. All this still ends up being cheaper than cable, which I guess is something.

I upgraded it with a second 300GB drive for expanded storage, and am looking forward to adding network capabilities to the TiVo, because the Home Media Option is also disabled by DirecTV, thus forcing me to hack it back in. Sigh. Other fun things involved in setting up this new box included running a second coax cable from the dish, and replacing the old circular dish with a 3LNB Phase III oval dish. I can’t wait to turn the old dish in to a parabolic microphone– but i need to find a way to finish the (currently textured) surface of the old dish with a glass smooth coating. I’m thinking a thick polyurethane? Or that stuff I’ve seen on tables that is a quarter inch or so of plastic.

What an awesome mothers day gift…

On a completely unrelated note, check out an ad for this website @ Filter a couple of weeks ago:

I’ve started another great summer of working on the reporting system for Bcfg2, and have been putting in my 8 hours each day. It is excellent fun at the lab as always, but keeps me extremely busy and makes me tired.

The Brother and Sister concert this weekend would have been really exciting to go to, but it turns out that I won’t be able to go, so if anybody else does and finds this, please let me know. Maybe the Blues Fest with my mom will be fun instead.

Narayan recommended the IT Crowd to me, a funny british television show about IT people. Its funny. Check it out on You Tube.
Look for the ones that are around 23 minutes, starting with “Yesterday’s Jam.” You Tube would be so great if it weren’t for the horrible performance and quality of flash video…

I hope very soon to move to a new server to make the site faster, but I’m going to need a free weekend for that, and I just don’t see one of those coming anytime soon. But alas, summer feeling good; there are many projects coming down the pipe.