300V in a battery

One of the exposure meters in my collection (a Radcal/MDH 1515) uses this Eveready #493 300V battery as bias voltage source for the ionization chamber used to measure x-ray exposure. The rest of the meter is powered by 4x2V rechargable lead acid batteries in a D cell form factor.

Looks like this battery was installed in December 2002. Last calibration date for the meter was 2003, so it was probably replaced when it was sent in for the previous calibration.

Installed December, 2002
Installed December, 2002

After 16 years of sitting on the shelf, the battery is pretty flat.

Dead battery
Battery’s pretty dead

Let’s take the cardboard off and have a look at what’s inside.

There are 10 plastic wrapped packs, each 1.3 cm x 2.2 cm x 6.6 cm long, all connected in series. Each pack appears to have 20 individual cells coated in a waxy type material and wrapped in plastic to hold them all together. With 200 cells, that gives 1.5 V for each cell.

Looks like there’s been a bit of leakage while the battery sat on the shelf for the past 16 years.

A little bit of leakage
A little bit of leakage

A close up of one of the packs.

Inside the Eveready 300V #493. Close up of the cells
Inside the Eveready 300V #493. Close up of the cells

Neat stuff.

More thrift store finds

In addition to the audio amp find, I also managed to catch an EICO 1030 regulated power supply being wheeled out to be put on the shelf. Naturally, I had to add that to my cart as well.

EICO 1030 power supply
EICO 1030 power supply

I’m starting to accumulate a bit of a power supply collection now, it seems.

Haven’t looked inside it yet, but I did plug it in and turn it on. Made the satisfying “thunk” of a big linear transformer being energized, and the 6.3 VAC terminals were putting out about 6.5 VAC (unloaded), which seemed reasonable.

A quick look around the Internets yields hits on various audio forms, so seems like a popular piece of gear in those circles.

While I was scoping out the electronics, Connie was over in the books and found a copy of Practical Antenna Handbook by Joseph Carr, so that went into the cart as well. No such thing as too many antenna books, right?

Good shopping day at the thrift store today.

Descent into audiophile-dom

This is how it begins, right? You’re in one of your favourite thrift stores just browsing around one day, and you spot this sweet looking piece of gear just sitting there on the shelf. It’s really cool looking. Your brain (and your wife) goes “Dude, get it”. Nevermind that you don’t know the first thing about audio except that it’s something your ears detect.

So now I’m the owner of what appears to be a double sided, very slick looking audio amp.

It’s a pretty hefty unit. The only labels on the amp are the DSM logo and a name plate saying who the amp was made for.

Audio amp name plate: Custom built for William H. Moody by DSM
Audio amp name plate: Custom built for William H. Moody by DSM

All the tubes emited a nice soothing warm reddish glow when I plugged the unit in and turned it on. Guessing that’s probably a good sign.

After thinking about it for a bit, I’m realizing that each side of the amp corresponds to the left and right channel coming from each device going into the unit.

I don’t know who William H. Moody is, and it’s unlikely I’ll ever find out. Whoever he was though, he probably liked his audio.

New Year hops

2019 hops

Noticed some new hops flowers on the vines at the hops tower as I was walking by this afternoon.

2019 hops
2019 hops at the MUSC Medicinal Garden hops tower
2019 hops
2019 hops at the MUSC Medicinal Garden hops tower
2019 hops
2019 hops at the MUSC Medicinal Garden hops tower

Back to school birthday

The first day of the 2019 spring semester happens to be the same day as my birthday. Connie had a great idea to do one of those First Day of School/Back to School photos that you see parents post of their kids on the first day of school. Seemed like a cute and fun idea.

She found a nice chalk board sign online and this morning we took a photo of me heading off to work on my first day of Back to PhD School.

Back to school birthday
Back to school day on my 49th birthday

Even though today is officially the start getting back to the PhD, I’ve been at it for a few weeks now. Most of my Christmas break was spent reading papers and finding out about the state of radiation dosimetry in dental radiography (a topic for another blog post).

49 years behind me. Heading into Year 50. Should be an interesting one.