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There’s no Need to Talk About It

December 28th, 2016

I’m Old Enough to Scope it Out and Keep it Loose

Sorry for the really obscure Amazing Rhythm Aces reference.

I have done the unthinkable. I have replaced my Bronze Age Hitachi oscilloscope.

To be more rigorous, I have SUPPLEMENTED my Bronze Age Hitachi oscilloscope. I don’t plan to throw it out, but I got a new scope which will probably see more use.

I got the Hitachi because I was nostalgic for the days when I used to be intelligent, i.e., the days when I was studying physics. I took two electronics courses in college, using Tektronix scopes, and when I decided to revive my interest, I found a creaky Hitachi offered for fifty bucks (maybe it was seventy-five).

My college electronics courses were truly, truly useless. I’m not sure why they bothered. They took the physicist approach, and physicists can’t do anything. If you want to know where an electron in a certain type of potential is likely to be at a certain time, a physicist can help you, but if you want to design a simple headphone amplifier, you might as well hire a bartender. Physicists learn nothing which is of practical use.

My first course was full of calculus, and it centered on the theory behind simple electronic components. We built ridiculous things like differentiators and integrators. When was the last time you went to Best Buy to look at a new 55″-screen integrator? Never! People don’t use integrators. They use stereos, computers, and smartphones. I didn’t learn how to make one useful thing.

My second course was called “advanced,” but it was about things like shining a UV light on a piece of metal and counting the electrons that left its surface. I’m sure Samsung pays top dollar to designers who can count electrons.

Say what you will about engineers. They may be creepy and scary, but they can actually do things.

The Hitachi was useful when I built guitar amps. I used it for monkey jobs, such as finding out how far a signal went in a circuit before being cut off by one of my wiring mistakes. You can’t do that very well with a multimeter. You need a picture, because AC signals on multimeters don’t tell you much.

Unfortunately, the Hitachi is an analog scope, so it doesn’t tell you anything. It just gives you a picture of the signal. If you want to know the voltage or frequency, you have to work it out with a calculator or multiply in your head. Up-to-date nerds use digital scopes. They have little readouts on the screen, and they tell you stuff about what you’re seeing. They also store information so you can look at signals later.

I don’t recall whether the Tektronix scopes I learned on were digital or analog, but given the era, I would guess that they were analog.

You can go on Ebay and get old digital scopes from American companies for not too much money, but they have certain parts that tend to blow, and you may or may not be able to fix them. Also, the cheap new Chinese scopes have more features. I decided to go Chinese.

The Chinese oscilloscope game is quite interesting. There are a number of companies that make scopes that look pretty much alike, and it seems like every budget scope costs exactly the same amount: $400. But it gets complicated. Some scopes are built well, and others aren’t. Some scopes can be hacked, and others can’t. You have to shop carefully.

The scope I got is rated for 50MHz, but here’s something interesting: the frequency is limited by software, not hardware. In other words, the manufacturer makes a scope that will work fine at 100MHz, and they program it so it only goes up to 50 so they can charge less for it. Weird. Naturally, nerds have found the hack that restores its full capability, so once I hack my scope, 100 MHz will be well within range.

There are other hacks for oscilloscopes. I don’t know what they are. I do know that the big drawback to low-end Chinese scopes is crummy software. They tend to have bugs that pop up, and people complain, and the manufacturers have to come up with solutions. It’s my understanding that American scopes are less buggy, which is one reason they cost four times as much.

It will be a little weird, turning on a new scope that does what it’s supposed to do, without requiring a nurse or a shaman to make it function. I haven’t had that experience in well over 20 years.

I found a neat resource: the forum at Eevblog.com. This is a website started by an Australian geek named Dave. I tried another forum, but the people were just a little too obnoxious. I don’t know why electronics turns some people into the fat kid from Pee Wee’s Big Adventure, but it does.

Dave’s videos are neat, too. He’s a real engineer (someone who gets paid to do electronics), so he knows a few things, and he spills his guts regularly on Youtube. He takes scopes apart, which is nice. I decided to get a Rigol DS1054Z largely based on his dismantling video. The scope looks a little “Hello Kitty” on the outside, but on the inside, the build quality is very impressive.

Will I ever need even 10% of the scope’s capabilities. Not this year. Well, that means not in the next three days. Okay, not in 2017. I think. But who knows what I’ll be doing in 2018? Can’t hurt to plan for the future. I would really love to learn a little about digital circuits, and you need a digital scope for that.

The Hitachi’s problems appear to be fixable, and I feel obligated to try a repair. On the one hand, it’s practically worthless even when running normally. On the other hand, it’s a sophisticated, top-quality instrument that must surely have cost over a grand new, so it seems a shame to turn it into a parts cadaver.

Why didn’t I fix it before buying a new scope? First, I am lazy, and I like to buy new stuff. Second, I was really dreading fixing it. Third, when you need to fix a scope, one of the things you should have on hand is…a scope. That works. I should find the Rigol useful while operating on the Hitachi.

I can’t figure out what “Eevblog” means. I believe “vblog” is Australian for “vlog,” but what’s “Eev”? I saw something indicating it means “electron volt,” but if that’s true, what does “eV” mean? Short answer: it means “electron volt.” “EE” means “electrical engineer.” That still leaves “v” to be dealt with.

Well, my brain must have been short-circuited. The “V” is from the “vblog” part, not the “EE” part. Okay, so it’s “EE Vblog.”

Australians. Whatever.

I remember Dice Clay wondering aloud whether we do nuclear testing there.

I think we do.

If I get the Hitachi to function, I will almost certainly write about it here. You have been warned.

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