Heathkit 10-10 Oscilloscope repair/usage

[electronics-whiz]

So I scored my first scope last weekend cheap at an auction. I got it home tried it our and I get no output on the display. It did come with the manual and I tried a few things with that with minimal luck. This appears to be from like the 1970s era and uses tubes and what looks like carbon comp resistors. All of the main tubes do glow, with the exception of V8 IV2. V11 is really bright when I put one tube in either the V2 or V6 socket (both are 12Bh7 in the manual) which makes me think I have a shorted tube. Also, the manual refers to these as 12BH7 tubes, the tubes in my unit are actually 12BH7A I don't know if that matters or not.

According to the manual if you don't get a trace remove the vertical tube then the horizontal tube. I don't recall now but V2 is one of them, and V6 is the other. If I remove one it is still dead, if I remove both when I power on I will get a spot on the display with a small pulse to it, the neon power pilot light does the same. Other times it will show a spot then it will move right or left and then vanish.

All of this is with no input on the vertical input on the scope, I have tried turning up the focus and intensity. I also see trimmers inside for both directions and for astigmatism. I have a friend that is an electrician/teacher I will try and ask also as this is something totally new to me.

Digital manual for Heathkit model 10-10
http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_IO-IP/IO-10/IO-10.pdf

[oldway]

We often discuss the choice of a beginner oscilloscope, a digital or analogue oscilloscope.

Speaking of analog oscilloscope, we mean a modern version transistorized and in good working order.

Here you have bought a brontosaurus vacuum tube technology oscilloscope and in a not working condition ...

Do not you think you exaggerated in the absurd? 

This oscilloscope can at most appear in the showcase of a museum and is no longer of any use at the present days.

In addition, tube technology is too dangerous for a beginner because there are high and lethal supply voltages.

Put this device in the dumpster or resell it and buy a modern oscilloscope that is in good working order.

Unless you are a collector, do not waste your time with such an antiquity.

Anyway, if you are a collector, here some informations about restauration of this kind of oscilloscope:

[Cyberdragon]

We often discuss the choice of a beginner oscilloscope, a digital or analogue oscilloscope.

Speaking of analog oscilloscope, we mean a modern version transistorized and in good working order.

Here you have bought a brontosaurus vacuum tube technology oscilloscope and in a not working condition ...

Do not you think you exaggerated in the absurd? 

This oscilloscope can at most appear in the showcase of a museum and is no longer of any use at the present days.

In addition, tube technology is too dangerous for a beginner because there are high and lethal supply voltages.

Put this device in the dumpster or resell it and buy a modern oscilloscope that is in good working order.

Unless you are a collector, do not waste your time with such an antiquity.

I think this guy got shocked by a tube once and is freaking out over nothing. Don't waste your time listening to this hater, there is nothing wrong with old tech. If properly repaired it'll still function perfectly fine. While there are high voltages everywhere (be careful), and heathkit scopes are not the best quality, they are simple and easy to understand how the circuits work. This is more 50s to 60s tech, anything starting from the 70s onward, if you buy it broken, they are hopelessly complicated to repair for a beginner. If you can, find a cheap (working) tube tester. Also, replace any electrolytic or paper capacitors (which are usually tubular shaped) and make sure the resistors read close to what they are supposed to.

EDIT: here's some more stuff on tube scopes: https://www.eevblog.com/forum/repair/barn-find-oscilloscopes/

[Paul Moir]

Be careful operating this oscilloscope without it's full compliment of tubes installed.  With one of them out and therefore the power supply less loaded, the voltage increases. To prevent this getting too high, it's absorbed by the regulator tube which is V11 in this case.  If you look at the schematic, V11 pretty much shorts across the B- line as it turns on.  That's why it glows brightly.

First step is to turn it on letting it warm up a minute or two.   Turn the intensity all the way up.  Turn the focus to mid point.  Turn the frequency to Horiz In (all the way to the left).  In a darkened room, now sweep the Horiz Center and Vert Center controls and see if you see even a dim glow from the screen.

[electronics-whiz]

If V11 is the regulator tube then I don't understand how if I have all of the tubes in it glows, but if I remove the one it dims to a low glow just like the others.
I have even left it on for like 5 minutes to warm up and still nothing.

I was able to get in touch with a friedn/ electronic teacher at the college I went to he said in a couple weeks he'd be available and said he had some spare tubes from something and seemed to think it may be repairable. I may just leave it as is until then while I know a good bit about electronics, transistors, etc tubes, scopes are pretty much a new animal to me. I know what scopes do, some of the attenuation adjustments, etc, but usually most things I see show digital scopes.

[tpowell1830]

Keep in mind that you need to run this in low light in order to see the trace on that old scope. The CRT is not top of the line to begin with and then factor in the age. I have to turn the lights out in order to see the trace on mine.

[electronics-whiz]

HMM that is interesting. I will have to try that, but unless it's really dim I would have thought I could see it indoors in my workshop/closet.

[Cyberdragon]

Also, it's IO-10 not 10-10. Just in case you need to search for it.

[Paul Moir]

I misunderstood.  You said V11 glows brightly when you put a single tube into either V2 or V6.  I assumed it glowed normally when you had tubes in both.  If one particular tube is behaving differently than the other, then something is clearly going on.

Also V8 should be glowing quite brightly.  The 1V2 in my IO-12 (much older design) is almost lightbulb like.  It has had trouble in the past with making good contact with the socket pins, requiring a little wiggle to coax it back to life.  I finally gave up on it and put in a high voltage diode.   Note to others:  this is the tube that rectifies the 1250v high voltage for the CRT, so if it isn't glowing, there's not going to be any hint of a trace.

[WastelandTek]

We often discuss the choice of a beginner oscilloscope, a digital or analogue oscilloscope.

Speaking of analog oscilloscope, we mean a modern version transistorized and in good working order.

Here you have bought a brontosaurus vacuum tube technology oscilloscope and in a not working condition ...

Do not you think you exaggerated in the absurd? 

This oscilloscope can at most appear in the showcase of a museum and is no longer of any use at the present days.

In addition, tube technology is too dangerous for a beginner because there are high and lethal supply voltages.

Put this device in the dumpster or resell it and buy a modern oscilloscope that is in good working order.

Unless you are a collector, do not waste your time with such an antiquity.

hogwash

do NOT dumpster this fine piece of equipment...ffs

I have a PILE of scopes here, I still use my restored O-10 quite frequently, do not listen to this puffery.

Replace ALL paper and electrolytic caps per the Carlson video linked above.

[floobydust]

I would recap the unit, change out all electrolytic capacitors, they don't last this long.
V8 HV rectifier filament glow, there is a shield inside so hard to see. If you're getting a trace, it's working.
I would check the +150V and -72V regulated power supply voltages.

With no tubes driving the CRT deflection (pulling V-deflection V3,V4 and horizontal V5,V6) you should get a centered dot.

[oldway]

This is absolutely not a fine piece of equipment...that's an useless bullshit....You can't measure nothing with this oscilloscope, it has no calibrated input attenuator, not even a calibrated time base...

There are a lot of cheap analog oscilloscopes to buy....

Buy some decent analog oscilloscope in working condition as Tektronix 465B, 2235, HP1740A or Hameg HM605....

[WastelandTek]

 

[oldway]

Try to post something more clever....

As I said, it may be o collector item, (but of very low value because they are not rare at all), but useless even for basic electronics.
Don't loose your time and money with it....

Problem with this oscilloscope is not that it is a vacuum tube technology, but that it has been made to be the cheapest vacuum tube technology possible.
In this time (years 60), Tektronix was making very good vacuum tube oscilloscopes....but these Heathkit oscilloscopes had nothing to do with this...It was a copy of old WWII era technology and fully outdated in the sixties.

I had one when I was a kid because it was all what my little money could pay.

[Cyberdragon]

Problem with this oscilloscope is not that it is a vacuum tube technology, but that it has been made to be the cheapest vacuum tube technology possible.
In this time (years 60), Tektronix was making very good vacuum tube oscilloscopes....but these Heathkit oscilloscopes had nothing to do with this...It was a copy of old WWII era technology and fully outdated in the sixties.
I had one when I was a kid because it was all what my little money could pay.

Have you ever thought that since he is a beginner maybe all he wants to do is see the signals?

[oldway]

Have you ever thought that since he is a beginner maybe all he wants to do is see the signals?

You are kidding ? Do you really think that you can see a signal with a  one channel 200Khz bandwith oscilloscope, with a multivibrator time base (not triggered base time), the worst sincronisation you can imagine, no calibrated input attenuator, no BNC input connector, the most bullshit oscilloscope you can find on the market.... and a beginner should use this in the actual technology....SMPS, Arduino, FPGA, even to test a 555 circuit, it does not serve...?

You can only be kidding....

[electronics-whiz]

This scope has BNC input, external horizontal input, a few other things I don't yet know what they do. Figured $10-15 for a first scope is not bad, if I screw up and blow it up I'm not out much. Right now I'd just like to look at some signals, maybe see if I have clean DC off a rectifier, mess around and see if I can see the bus frequencies on an old Pentium 3 motherboard.

There is no point dropping $$$ on a fancy scope when I still have to figure out the beginner part. I have no real plan to use in any real complicated testing, etc. I don't see how this wouldn't be worth at least trying to fix. If it's a $15 scope and $150 to fix it then maybe not worth it. Seems even older scopes online still sell for like $100+

[oldway]

http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_IO-IP/IO-10/IO-10.pdf

This scope has BNC input...

Only if it has been modified or if it is not an IO-10 heathkit oscilloscope.

maybe see if I have clean DC off a rectifier

And how do you do to measure if the ripple is in the specifications of the service manual ? No way to measure anything without calibrated vertical input attenuator. NB: no need of an oscilloscope, use your multimeter in AC voltage to know how much ripple you have.

mess around and see if I can see the bus frequencies on an old Pentium 3 motherboard.

Nope...

[Cyberdragon]

Most old scopes have been modified (really only get them if they have been). Again, he is new to scopes, he needs to learn how to view signals fist before he can measure them. So a 200Khz untriggered viewing only scope is plenty good enough. Yes, he will eventually need to upgrade, but wait till he's ready before shoving a bunch of buttons and knobs at him. That is far from the worst "oscilloscope" ever made. Look up the Waterman Electronics Pocketscope and be afraid. Now that heathkit looks fancy.

But no, it won't work on any computer motherboards. It'll be fine for simple breadboard circuits, audio, and PWM stuff though.

[oldway]

So a 200Khz untriggered viewing only scope is plenty good enough.

  Yes, using his CRT to make a clock....and nothing more

It'll be fine for simple breadboard circuits, audio, and PWM stuff though.

...To sincronize that oscilloscope on a PWM signal  

Two channels and 20 Mhz minimal bandwith recomended for a beginner. 

[mcinsand]

Any update on the scope project?  I've always liked the simplicity of the IO-10, and it's useful for some of the things at my bench, such as sweeping a VCO and looking at resonant circuit responses.

[bd139]

Indeed. Interesting thread. It's either been abandoned or OP killed himself on it 

My second scope (the first one doesn't count as it wasn't actually really mine) was an IO-12 which could just about slew to 5MHz if you pushed it. Perhaps surprisingly if you know a few tricks you can actually get these as usable instruments into the 100MHz+ range with some compromises but not a lot of people know that (down-conversion, sampling, demod probe, power detector etc). Relative measurements are quite useful too which it's capable of as well. There's a whole education in bending low specification tools to get the information you need out

[mcinsand]

>>Perhaps surprisingly if you know a few tricks you can actually get these as usable instruments into the 100MHz+ range with some compromises but not a lot of people know that (down-conversion,
>>sampling, demod probe, power detector etc).

Don't forget about using inductive compensation to increase interstage bandwidth.  Your IO-12 might have enough room under the hood for such tinkering.

>>There's a whole education in bending low specification tools to get the information you need out

My first tutor was a near-nonagenarian when I met him in the 1990s.  He was the person for HF and VHF radio repair in Western NC, and he got his start working on the very early radar systems for the military.  He was a tremendous help when I was working on my first project: a Heathkit HW-101 transceiver.  I remember noticing an ancient DuMont scope on his bench during one of my first visits, and I'd learned enough to know that it had a bandwidth of maybe 1 MHz.  So, I asked if it was there just for decoration.  He laughed and said that, no, it was his workhorse scope.  No doubt that he learned how to do more with limited bandwidth during his radar days, but he did know how to diagnose, design, and repair like I doubt that I ever will.  Scopes and test gear with electronics are definitely like tools in other fields; better to have a skilled person with limited tools than an unskilled person with top of the line.

[bd139]

Exactly.

High bandwidth scopes are a relatively new thing as well. If you look at the Saturn V Instrument Unit, it uses C-band transponders on it (4-8GHz) back in the early 1960s. No oscilloscopes that fast then! It was all frequency domain and you can get your SA output on 1 MHz DuMont fine and he knew it

[oldway]

It should not be exaggerated. 

We are on a forum where some people do not hesitate to say that an analog oscilloscope is totally useless.

I do not agree with that.

But come to argue that an oscilloscope whose technology dates from the WWII is usable by a beginner, there is an exaggeration.

When Dave is looking for an analog oscilloscope of less than US $ 50 on Internet, he is looking for modern decent oscilloscopes of 20 or more Mhz, not this kind of antique crap scope that no longer belongs in an electronics workshop at the moment.

Yes, it can be a museum piece and I leave it to collectors the right to waste their time and money on this kind of apparatus .... It serves, yes, to show it still works to the visitors of the museum and nothing else.

I can write about it because I had a IO-12E in the past and the first thing I have done was to buy a 7 Mhz BEM  003 MBLE when I had enough money to replace this piece of shit.