Technicial Oscilloscope Question

I assume the tube is in a socket. Pulling the tube and spraying some contact cleaner in the socket might fix the problem. It could also be any one of the switches and pots. I think tubes went away sometime in the very early '70s. HP and Tektronix even earlier.

Pete

Charlie, tubes lasted well into the 70s in consumer electronics but major players in industry fazed them out as soon as suitable solid state devices became available. I was referring specifically to scopes.

Pete

Charlie;

Scopes are neat as well as very handy.

\you should maybe Google oscilloscope and you will find a wealth of info on how they work and what they can do.

Be aware that to see a waveform, first of all you need an oscillating input source of some sort, as well as a trigger that fires the scope at some point on the waveform, usually somewhere on the leading edge on a +ve going voltage.

Rod

I haven't actually replaced the tube yet, just ordered one. ECC83. I believe common current use is amps. Most of the one were listed as pairs, for replacement in tube amps. You just can't get the same sound out of modern type amps as compared to the old tube amps.

 http://www.tek.com/

Kent, I meant the use of tubes in Tek scopes, not the scopes themselves. I am sitting next to three of them as I type this.

As for tubes, I know they are still used in many applications. I recently changed a thyratron in an Argon laser. I also have a cabinet filled with about 200 tubes gathering dust.

Pete

No offense, but if you really want a 'scope, do yourself a favor and buy a working one.  If you check on eBay there are all kinds of deals.

A good choice for a new Oscilloscope is the Rigol. Used scopes like Tektronix are abundant on ebay. A good choice there is the 22xx series. The tube type Tek scopes went away in with the 50's for the most part.

As for tubes, I think the last vacuum tube manufacturing, I think RCA, closed in the US about a decade ago. Tubes are made now in China and Russia and will probably be around for many decades. Old stocks of tubes are substantially available and are not going away very soon.

Dale, if we're ever in a nuclear war, I doubt my first though will be "does my 'scope work".

Chuck, I don't think I'd start with the Rigol, but it's a fine unit.  He can have a decent little unit for $100 or less, certainly less stress than screwing around with an old tube unit.  It'll also be a digital model, which is far more useful than the old analog ones.

Anyone have any recommendations for a simple PC based scope? All I want to do is to be able to see noise on my powerline, and I'd rather be spending my money on train-related items. Hantek is a name that comes up on Amazon and eBay, but I don't know anything about them, or if there's anything better out there.

Thanks

Jim Madigan

Agreed on all. But for new, the Rigol at $399 is a bargain I think. It has a built in counter, multimeter of sorts, and digital storage. And comes with two probes. I thought it was a show special when I bought one, but seems like the price is holding at this level. By contrast, the least expensive Rigol multimeter is $449. Go figure.

I have a college-level electronic text book that I used back when I was in school. The chapter on troubleshooting opens with these words:

"The first thing one should do when a piece of electronic equipment fails to operate properly is to deliver a sharp blow with the heel of the hand to the top, front, back and sides of the unit. Many times this will restore normal operation."

This was from the tube era. Often a little corrosion would develop between the male pins on the tube and the female tube socket holes. A tiny vibration would often move the tube just enough to loosen the corrosion, restore the contact and "...restore normal operation." It wasn't FIXED, but it was WORKING.

That may be the case here, however when you pull out the old tube and put the new one in, you will have "cleaned" the tube socket contacts. I'll bet you could put the old tube back in at that point and it would work, too.

Reminds me of a research chemist i know who bolted a vacuum pump to the side of an instrument with a sticking mercury plunger relay. The vibration was a good fix. Function over form...scientists.

I dabble a little in vintage high-end audio equipment, and can assure you that the vacuum tube is not dead. There are several audio tubes that are being reproduced these days.

That being said, a contact cleaner known as DeoxIT is popular around the audio circles as a good tube socket and rotary switch cleaner. If a shot of contact cleaner or a replacement tube can be had cheap, try to get it running again.

The audio folks like the tube sound, i think probably a more pleasant distortion than the harsher transistor sound

Deoxit is a product of Caig Industries. Radio Shack had that at one point as i read on the label of their cleaner.

I use DeoxIT D5 all the time on contacts around the trains, great stuff.

I have some field audio recording equipment that I use when recording the group I sing bass with. The mic preamp I use is a small, tube-type preamp, with two 12AX7's in it. Nice, clean sound.

None taken. I don't know what I'll do with one. He asked if I wanted it, and I always wanted to mess with one so I took it. Now beyond replacing the tube and a little contact cleaner I won't mess with it. I have enough projects. I'll probably throw it away, so I won't be temped to waste a lot of time on it.

I use a couple of Caig labs products.

I think they work well.
I use their fader lube to clear up noisy pots.

Speaking of tubes (off topic), here is an interesting bit on a company Audio Power Labs that still builds with tubes, 833s. They also collect "heavy metal". Tube type transmitters. An interesting array of Collins and RCA Comm and Broadcast transmitters too.

It get interesting at about 9 minutes in.

http://www.youtube.com/watch?v=eEuNUE9hnM0