Tektronix 213 Scope repair

[nsubulysses]

213 DMM Oscilloscope

I am really tempted to buy this, although I know nothing about fixing oscilloscopes. I could probably get this for $30 or $40. the seller has had it listed for months and the price keeps dropping.

All I know is that it either doesn't turn on (that would be nice, could be easy fix), or turns on and makes no display when you adjust the buttons. It basically doesn't work. Anyone know what I might be getting myself into, or have any advice? If it can be said, what usually fails first on old scopes. I would guess caps, but do CRT screens burn out. Can they be replaced, etc.? Does this have obsolete parts, etc. ??

There is some info here -- https://www.youtube.com/watch?v=czv_8d66IQU#t=1311

Dave loves it. The Tektronix 213 is a 1 MHz oscilloscope and a DMM.

[Jazz P Bass]

As that scope was made in 1975, I would pass.

For sure, a recap job will be in order.
Plus it has an itty bitty screen.
And if it is a bad CRT, forget finding a new one.
You will also have trouble with drop in replacements if any transistor are bad.
1975 was not exactly the height of perfection, transistor wise.

Here is a link that has the schematics if you are interested.
213 - TekWiki

[nsubulysses]

Hey, it could be from 1988

thanks for the link

[Jazz P Bass]

True enough.

In that case the transistors may be easier to find.

[jbltwin1]

Broken scopes of that era should be free> No parts and needing to be re-habbed. You can buy a working one for 100.00

[Chuck H]

+1 to all above.

Unless you WANT to fix something, working scopes are easy to get for under $200. The trouble and/or expense of repairing a broken one just doesn't seem like an equitable use of time or money.

When I took "the next step" (outfitting a proper bench beyond just a DMM) I picked up a scope, signal generator, built a dummy load, built and loaded my lead wire rack, made a cap tester, the cursory 100W bulb current limiter, bought overhead lamps and lumber for a bench and shelves all for under $500. Some of the best money I ever spent.

[Mick Bailey]

For anyone with a CRT scope I can recommend the Tektronix troubleshooting manual. The introduction also discusses the troubleshooting philosophy that can be applied to any electronic problem.

The PDF can be found here (3.6Mb);

http://www.sphere.bc.ca/test/tek-par...ing-scopes.pdf

[nsubulysses]

I guess I am drawn to the challenge of fixing a scope, and that thing is kind of cool. Thanks for all your input. I should probably stay away. I am not really in need of a scope. only if it's a killer deal am I tempted to buy i.e. under $50.

I have 4 oscilloscopes that totaled $200 -- 2 Tektronix 465B scopes for $100 each, a Tektronix TDS 210 I got for free from my uncle (thanks motorola storage closet), and a BK Precision 1477 (was on CL "working" for $30. I went to go buy it but couldn't get the trace to stop moving all over the screen, so the guy just gave it to me. I cleaned the pots and jacks and it displayed a stable sine wave).

[Chuck H]

Well there's your answer then. And a perfectly reasonable one at that

[g1]

Well see if he will take less than $50 then. If you're up for the challenge and have worked on scopes before, then it will at very least be a learning experience. Could be as simple as the rechargeable battery which apparently is a common problem with these.

[km6xz]

The scope was later, after Tek bought out Sony in and changes the markings from Sony/Tektronix to Tektronix. It was a cool little scope in its day and very expensive. Depending on the problem, it should not be horrible to repair unless one of the Tektronix made custom chips and hybrids are defective. When working, even the CRT, it should outlast any new Chinese scope, all the parts are very conservatively rated. Most the CRTs last almost forever. Power supplies and high voltage generator are the two most common sections to go out and the symptoms are consistent with that. Contact the sell and ask if there is any indication it is powering up even if the CRT is not lighting. If nothing is getting power, the power supply section would be an easy one to fix because it uses standard parts.
If it was me, I would get it but I have worked on hundreds of test instruments, many made by Tek so it could not scare me off at all. But it can be a problem to diagnose since you do not have the extension cables needed to run it with all the boards exposed. The circuits are straight forward and easy to follow the schematics. They did not generate a lot of heat so I would be surprised if the filter caps need changing. There might be one just plain shorted however and any replacement now would be smaller and cheap.
I would rather have that scope than any of the scopes intended for general bench work like B&K or Sencore, Heath etc. It will sure handle overload better than the new cheap LCD scopes. Bandwidth is pretty limited however, the only downside.
The battery is required if it has the battery option. The battery is probably bad by now so that could be the entire problem if it does not even turn on. Ask if it has the battery option.

[nsubulysses]

Hey Stan thanks for chiming in. I have a question though, I thought the battery was just an option and that you could also plug it in with an AC cord to power it. Were there more than 1 version, with one being battery only?

EDIT: nevermind tek wiki says it is either battery or line powered.

I'm probably gonna get it. It's a cool little scope and I am down for the challenge of repair. If it can't fix it, no big loss.

[nsubulysses]

I'm imagining this and a dummy load, and a sig generator on my phone being something good to have when going to buy vintage amps that may or may not work. Or cases of on site repair on a huge or unmovable unit. DMM and scope in one

[km6xz]

The battery is the power supply for the scope. The AC power supply is a battery charger which trickle charges the battery whenever it is plugged in. It can be AC powered only when there is a functioning battery in it. . It is a large battery, doubles its weight but still quite small in size and weight ideal for field service. A lot of test instruments work the same way from Motorola, H-P and Fluke lab series. The batteries are NiCad which if left uncharged for a long time is surely bad and corroded. You can make your own battery using 1.2 volt SubC cells which are a little smaller than C cells and have solder tabs on the ends. The trickle charge of batteries is a safety and well as portable operation feature since there is no earth ground or AC ground reference for the scope portion of the circuit, it is fully floating.

A few more bits of interest. The deflection factor is really wide range, calibrated to 100v/div and uncalibrated to 250v/div so you can look at higher voltages than most scope without a divider probe. Most Tek scope have a 5v/div with 1:1 probe. The 213 was intended for industrial applications where power potentially very high. So it is perfect for tube guitar amps with their higher plate voltages scopes are happy with.

[nsubulysses]

Well of course I couldn't resist. The batteries are corroded as everyone suspected and the 0.2A fuse is blown. There is also corrosion around most of the plugs and sockets that connect different PCBs together. I have not gone into it at all at this point other than that. I guess I will order up the batteries and fuse and then start cleaning the corrosion and checking the electrolytics. This thing is actually way smaller than I thought it would be, which I think is really cool. I hope I can get this working because it is really damn cool!