Old oscilliscopes - should I harvest them for parts?

[mthibeau]

I was given three vintage oscilliscopes:

A really old tube based Tektronix (Can't remember the number- I think it is a 545)
- It has a lot of tubes, carbon comp resistors, ancient diodes and tons of pots, switches and stuff that seems useful for pedals

A more recent Tektronix model 435
- No tubes, lots of ICs and other parts

An even more recent Tektronix model (the modular one)
- No tubes, lots of ICs and other parts

Looking at Ebay and Craigslist, non-working oscilloscopes are pretty worthless. I had been given a 4th one (a Leader with a big screen) and it works so I am keeping it.

What should I do with these, just chuck them, or try and harvest some parts from them? The tube one is very interesting due to the "mojo" looking stuff in there.

I also don't want to get electrocuted, so any tips would be helpful

- MikeT

[pakrat]

I would harvest those bad boys. If you don't feel like going through the trouble, you could always pull the boards and take stuff as you need it and chuck the rest.

[asfi]

Well, my inclination would actually be to use the working scope to try to get the other three working. Tek scopes are true workhorses, and if they're alive and well their value to a tech exceeds their cash value.

That being said, the oldest of the three would be the hardest and most expensive to get going again, as if it's in original condition it will need new electrolytics, probably any number of new tubes, possibly even a CRT too. But if you want elite tube-tech skills, it would be a heckuva worthy project. But only if....

The 435 may just have a loose chip in its socket. Apparently that's a common fault with Tek scopes of that vintage. Pull it apart, re-seat the ICs, put it back together. If it's still dead, you haven't lost much.

The nice thing about Tek scopes is that the service manuals are excellent and PDF copies are out there. 

[amptramp]

The edebris site has this:

http://bama.edebris.com/manuals/tek/

It looks like they have gone from Deja Vu to the more common .pdf format.

[armdnrdy]

I also don't want to get electrocuted, so any tips would be helpful

Unplug it before you start dissecting components! 

[Thecomedian]

dissipating voltage from caps is important.

http://www.overclock.net/a/capacitor-safety-in-power-supplies


if you've got any high power caps, short them safely to make them safe to work on.

[CodeMonk]

Cannibalize them.
If you don't, you have to hand in your DIY card.

[gjcamann]

If only those scopes had JFETs in them, then it would definitely be worth the trouble. I got a lifetime supply of 3904's and 3906's from some old O-scopes plus a whole bunch of propretary tek tranny's that I have no idea what to do with. It may or may not be worth it. If they're socketed then why not take a minute to pull them.

I agree - keep the one that's working.

[drewl]

I used to work on those years ago.
I scavenge everything for parts and those old tube Tek scopes are full of good stuff, old RCA 12AX7's and 6550's.
They used to come with a little spool of silver solder in them for repair!

As mentioned be careful draining caps and the CRT.
Smartass co-workers would smack two pieces of wood together when I was dischraging the CRT, scared me to death!

[tubegeek]

Savvy tube DIYers swear by the ceramic terminal strips inside the old Tek scopes. Also (supposedly) the 6DJ8's are the very best quality for that type.
Pretty much ALL the parts are top quality.

[amptramp]

As mentioned be careful draining caps and the CRT.
Smartass co-workers would smack two pieces of wood together when I was dischraging the CRT, scared me to death!

Many years ago, I was working on a multispectral camera which was flown on a DC-3 and scanned side-to-side and had a rainbow colour filter on it so scanning fore-and-aft changed the colour in view.  The image dissector tube that was the heart of it was donated by the customer and was $15,000 (in 1973 dollars).  I had a problem that required me to pull the tube, so my boss and the technical director were standing by when I did this.  The technical director didn't like me and the feeling was mutual.  As I very carefully pulled the tube out of the socket, I stepped back on a piece of bubble wrap.  The shock he felt was enough that I could see a physical decline in him from that point on.

[J0K3RX]

Use the old one that works and make a tracker/octopus out of it...

[ch1naski]

As mentioned be careful draining caps and the CRT.
Smartass co-workers would smack two pieces of wood together when I was dischraging the CRT, scared me to death!

Many years ago, I was working on a multispectral camera which was flown on a DC-3 and scanned side-to-side and had a rainbow colour filter on it so scanning fore-and-aft changed the colour in view.  The image dissector tube that was the heart of it was donated by the customer and was $15,000 (in 1973 dollars).  I had a problem that required me to pull the tube, so my boss and the technical director were standing by when I did this.  The technical director didn't like me and the feeling was mutual.  As I very carefully pulled the tube out of the socket, I stepped back on a piece of bubble wrap.  The shock he felt was enough that I could see a physical decline in him from that point on.

Priceless. Just priceless.

[esauvisky]

I was given three vintage oscilliscopes:

A really old tube based Tektronix (Can't remember the number- I think it is a 545)
- It has a lot of tubes, carbon comp resistors, ancient diodes and tons of pots, switches and stuff that seems useful for pedals

A more recent Tektronix model 435
- No tubes, lots of ICs and other parts

[...]

If you have plenty of free time, I command you to build a Tennis for Two console with your working one
Tennis for Two was the first electronic game with a graphical display.

[duck_arse]

and let's not forget that crt's were used as storage, like memory, in very early computers.

don't ask me how, though.

[alfafalfa]

Savvy tube DIYers swear by the ceramic terminal strips inside the old Tek scopes.

I have hem lying about somewhere waiting to be used for a really special project.

[mthibeau]

So I finally got around to disassembling the next to oldest one (the boards inside say 1965, 68 and 72), I can't believe the # of transistors that were in there, all socket-ed . I need to sort them and cross reference the Tektronix part # to regular 2nXXXX #s to see how useful they are. There were some neat dual transistors as well, including these white guys with 6 legs with NPN on one side and PNP on the other. A few are definitely germanium, hope they wind up being useful.

There are also many dogbone capacitors on the boards, carbon comp resistors, and some cool looking diodes (a couple of gold ones too, that look like real gold).
- I couldn't find any info on people using dogbone caps for guitar effects, any reason why that is the case?

Thanks for everyone's help. I haven't started tearing apart the tube oscilloscope,  but when I do I'll definitely keep the ceramic terminal strips, and the tubes, tube sockets, etc. There are some ancient looking diodes in this thing, as well as a ton of weird coil like things I have no idea what they are...

- MikeT

[psychedelicfish]

Thanks for everyone's help. I haven't started tearing apart the tube oscilloscope,  but when I do I'll definitely keep the ceramic terminal strips, and the tubes, tube sockets, etc. There are some ancient looking diodes in this thing, as well as a ton of weird coil like things I have no idea what they are...

Take care! make sure to discharge all the electrolytics, and make sure to dispose of any leaked PIO caps safely, from what I know the oil in them has some pretty nasty chemicals in it
Thanks,
Edward

[amptramp]

It wouldn't be too difficult to convert (pervert?) a scope into a fuzz that will show you exactly what it is doing to the waveform.  Seriously, somebody should do this.  Just inputs to the regular scope inputs, outputs from the vertical amplifier and you can watch it all.

[mistahead]

Sounds cool - I think I have an app for that...