One of my hobbies

A freewheeling astro-salon.

One of my hobbies

Postby michael-lloyd » Mon Apr 13, 2015 9:22 pm

I have a few things, hobbies if you will, that I have been involved in for most of my life. Would be astronomer is one. Here's a hint for another. Anyone care to guess what it is?

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“I have never been lost, but I will admit to being confused for several weeks” - Daniel Boone

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Re: One of my hobbies

Postby steve-fung » Mon Apr 13, 2015 11:39 pm

Hmm... These look like a vacuum tube, two transistors, and a diode. You're into electronics, audiophile, radio, or something related?
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Re: One of my hobbies

Postby michael-lloyd » Tue Apr 14, 2015 6:00 am

Hobbyist electronics. I've been restoring old tube test gear and radios from the 20's thru the 60's. The tube gear started as a ricochet off of my Ham radio hobby. I have wanted the Drake "twins", R4B receiver and T-4XB transmitter, for a long time and I found a pretty good deal on a nice clean set so I bought it. When I opened the receiver up I realized that I didn't know enough about tube radios to work on them so I bought a basket case AM radio for 10 bucks and started teaching myself how to repair it. I'll save the long story but that restoration triggered test equipment restoration and here I am.

I used to make boards and play around with that but SMD's aren't getting any larger and my eyes aren't getting any better. I recently picked up a small board mill so I guess I still make boards. That said I made a board for a power supply for an old farm radio that I have (see below) last weekend. They originally ran on 135V, 22V, and 7.5V batteries. Most of the "portable" radios ran on batteries with those ranges but you can't get them anymore and why would you want to :)

To be honest, I think I designed the board (not the circuit) a little too tight. I used 32 mil traces but I'm not sure it's not going to smoke like a turkey at Thanksgiving when I put power to it. My circuit board mill locked up and is off for repair otherwise I would have already redesigned the board with more space and wider traces on the higher voltage legs. Max current is 2A.

Screenshot of the board

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The populated board. Note the high end, precision silk screening

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The mill cuts very clean traces. This is a shot of the power supply board. A couple of traces were not cut through (lower left) as a result of the mill starting to fail.

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I'm currently working on an old Knight Oscilloscope. At 5MHz bandwidth it's not much competition for the Tek scopes that I have but I thought it would be fun to rebuild. I have a little board that I can use to make it display time once it comes back to life. It seems kind of rude to turn the old scope into a clock though.

This panel has been cleaned up and polished as best as possible since this picture. The scope is in pieces but hopefully it'll be back to life by next weekend. It really depends on parts, free time (mine), and motivation (also mine). My real job sets 2 of those parameters for me.

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Chassis before:

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Current state of the chassis. Waiting on parts. The story of my life. New tube sockets are proving to be a challenge to find. The board sockets are still good but the two on the chassis were pretty crappy:

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Most things do not get torn down to the bare chassis. This one needed it. Both circuit boards have been cleaned up. I had to replace a lot of resistors that had drifted out of tolerance. All capacitors get replaced. So far I've never tested an old capacitor for leakage that wasn't bad. I rebuilt the leakage tester that I use (Eico 950B) and have a higher end leakage tester in the que for rebuilding. While this one is waiting for parts I have started the repair of a Heathkit Signal Tracer. That's how it goes, tear one apart, clean it up, while waiting for parts, repair another one...

I don't "restore" as in stuff old caps with new parts. My goal is make it work not make it look original, though I do try to keep the exterior as original as possible. Some of the gear, like signal tracer, VTVM, etc is used for AM/FM alignment and troubleshooting.

I have a back log of old AM radios and a pair of AM/FM radios that need to be gone thru. I like working on the test equipment so I get to it first. The radios are a little more work because their cases (wood and Bakelite) need attention too. My oldest radio is a RCA Radiola 44 "farm radio" from 1929. I picked it up at a local flea market. Unfortunately it's base is pot metal and it has failed. I've been researching how to make a new base from aluminum. That may take me into the world of milling machines :)

Radiola 44. This is not mine. I wish it was. This was a portable radio back in the day

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Re: One of my hobbies

Postby rodger-jones » Tue Apr 14, 2015 7:21 pm

Just out of Highschool got into shortwave listening. I was repaired a Hammarlund Superpro and a National HRO.
The Superpro almost electrucuted me. :-) :-)

I refurbed some old test equipment too (Tektronix 535 among others)...

I also built circuits for fun. Only very simple PCBs. Not as sophisticated as yours.

SMD and kids put an end to that hobby..

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Re: One of my hobbies

Postby michael-lloyd » Tue Apr 14, 2015 8:10 pm

Yeah.. I got away from electronics for a few years. Kids, work, life, etc. I am still not giving up on SMD's but they sure have added "color" to my language. Truth be known, I've learned more about electronics poking around, carefully, in old tube radios and test equipment than I ever did with the discrete stuff. But... back then I didn't have a bajillion forums and YouTube to watch.

For example, check out this guys channel he has unbelievably thorough videos:

https://www.youtube.com/channel/UCU9SoQ ... _3GxeteQPA

And this guy (Tek field service rep and really nice guy):

https://www.youtube.com/channel/UCiqd3G ... _IBt7p_LjA
“I have never been lost, but I will admit to being confused for several weeks” - Daniel Boone

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Re: One of my hobbies

Postby steve-fung » Wed Apr 15, 2015 1:46 am

Michael, that's pretty amazing stuff you're doing there. Mostly analog electronics? In case of apocalypse, I know who to turn to for technical help.
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Re: One of my hobbies

Postby michael-lloyd » Wed Apr 15, 2015 6:21 am

Mostly analog electronics. Some power. In the back of my mind I think it would be useful to build a solar charge controller.

I have an Arduino or two :) Raspberry Pi's are kind of cool considering they are basically a 486 computer that will fit in your hand. I have one of those that I use to control a little quad copter. I didn't write any of the software for it though. I bought a Beaglebone Black (who names this stuff???) but I haven't had a chance to delve into it. I try to stay away from places like Adafruit and Sparkfun. They have way too many "cool things" to buy.
“I have never been lost, but I will admit to being confused for several weeks” - Daniel Boone

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Re: One of my hobbies

Postby melanie-black » Thu Apr 16, 2015 11:07 pm

I've got an electronics degree, but haven't tinkered with anything in years due to many factors. Would have to do some reading if I got back into doing any kind of circuit designs. Hooking stuff up and soldering, though, no problem.
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