Ratdude's first scope

**PeteS in CA** · 03-08-2012, 08:41 PM

Re: Ratdude's first scope

I probably used one of those in high school. IIRC, a lot of old tube consumer electronics connected AC Neutral to the chassis. So step one, IMO, should be to find out whether one of the AC cord prongs has continuity to the chassis and/or case.

**KeriJane** · 03-08-2012, 09:35 PM

Re: Ratdude's first scope

Ratdude...

Congratulations!

That's an ideal first scope. you can learn a great deal with and from it.

It's all tubes, right? Learn about them. Practically no one else under 30 has and vacuum tubes have some unique characteristics as compared to semiconductors... characteristics that might be extremely useful in a 'scope.

I wouldn't change the cord just yet if it's functional.
You might want to look at it to see if it's connected to chassis.
It might well be pointed out in the manual which is an invaluable study guide.

Tying the case to ground wasn't necessary in 1966 and could possibly affect operation as it might affect shielding. Of course all of the insulation is pushing 50 so... it's an even better idea to study that manual!

I prefer "live" scopes like yours over the digital ones... lag drives me nuts.

Congratulations again

**Sparkey55** · 03-08-2012, 09:59 PM

Re: Ratdude's first scope

I have that same Heathkit model. Will eventually get around to a restoration in the future.

**Agent24** · 03-08-2012, 10:15 PM

Re: Ratdude's first scope

Looks nice! Yours actually has division labels on the knobs. Better than mine...

**ratdude747** · 03-08-2012, 10:22 PM

Re: Ratdude's first scope

the prof also has a vac-tube based volt meter... it has super high impedance... he says he isn't sure if he will keep it or give it away...

his office has half of his collection in it... the other half is for home use. he has a bunch of devices stacked, all made from kits and most of them quite aged.

the thing is that heathkit manuals do not exist in a .pdf... the prof says that anybody who posts a pdf gets a cease and desist letter from them (aka lawsuit).

I doubt the neutral is tied to ground... it doesn't have a polarized plug, which makes finding neutral vs hot ambiguous...

I will leave the cord anyway... the unit may be worth something as since it is in such good condition and it still has the manual... having 100% stock parts makes it that much better.

this is not my first time using a scope btw... the labs at my college have both analog and digital scopes... we learned how to work analog scopes at the start of this semester; the first lab was solely on the use of an analog scope.

**Agent24** · 03-08-2012, 10:59 PM

Re: Ratdude's first scope

Originally posted by ratdude747

the thing is that heathkit manuals do not exist in a .pdf... the prof says that anybody who posts a pdf gets a cease and desist letter from them (aka lawsuit).

That's a bit stupid for something that old...

**Toasty** · 03-08-2012, 11:17 PM

Re: Ratdude's first scope

Here:

Houston - We have a problem. Site keeps changing .gifs to .jpg's and shrinking them. STOOOOOOPID.

Be back shortly with a jpeg that works...

Okay. Let's try this again:

Attached Files

**Th3_uN1Qu3** · 03-09-2012, 05:29 AM

Re: Ratdude's first scope

I think there's a mistake on the schematic. On the right, at the HV output after the 1V2 tube, the first cap is labeled as 1000v while the voltage at that point reads 1400v. That cap should be 1600v like the one to its left.

**ratdude747** · 03-09-2012, 08:08 AM

Re: Ratdude's first scope

i know he swapped a 200v cap for a 400v cap as per a penciled in mark in the manual.

**berniedd** · 03-09-2012, 09:55 AM

Re: Ratdude's first scope

Originally posted by Agent24

That's a bit stupid for something that old...

Cease and Desist Letter from who? I thought the Heathkit company closed down years ago.

**Toasty** · 03-09-2012, 10:08 AM

Re: Ratdude's first scope

Nope:

http://electronicdesign.com/article/...heathkit-20689

http://www.heathkit.com/

.

**PeteS in CA** · 03-09-2012, 04:35 PM

Re: Ratdude's first scope

I remember Heathkit VTVMs from high school, too. Try talking to a modern young tech or engineer about their voltmeter having to warm up before it can operate ...

I work with vacuum tubes pretty much every day ... aka TWTs.

**Toasty** · 03-09-2012, 04:42 PM

Re: Ratdude's first scope

You work with TWATs? How lucky can you get!

**Jack Crow** · 03-09-2012, 08:17 PM

Re: Ratdude's first scope

R,
Looks like a good start.
With a minimum of care it should last another ten years or more.

You can do a lot of good stuff with that.

I presume you can set it for X/Y display?
If so, I will re send a sketch for a cheap semiconductor curve tracer.
Made a lot of money with that tool over the years.

A simple and cheap gizmo that will let you look at diodes and transistors and see real fast (as in 60 times a second) if the junction is any good.

Keep it safe
Jack Crow

**PeteS in CA** · 03-10-2012, 12:02 AM

Re: Ratdude's first scope

Yep, Toasty. I connect some to 3.8KV and some to 4.2KV ... after warm-up, of course.

**Agent24** · 03-10-2012, 09:07 PM

Re: Ratdude's first scope

Originally posted by Jack Crow

I presume you can set it for X/Y display?
If so, I will re send a sketch for a cheap semiconductor curve tracer.
Made a lot of money with that tool over the years.

A simple and cheap gizmo that will let you look at diodes and transistors and see real fast (as in 60 times a second) if the junction is any good.

That sounds like a useful tool - but I think my scope is too basic for that.

Would a curve tracer by any chance do a similar job to this: http://www.siliconchip.com.au/cms/A_112767/article.html ?

**ratdude747** · 03-11-2012, 01:40 AM

Re: Ratdude's first scope

Originally posted by Jack Crow

R,
Looks like a good start.
With a minimum of care it should last another ten years or more.

You can do a lot of good stuff with that.

I presume you can set it for X/Y display?
If so, I will re send a sketch for a cheap semiconductor curve tracer.
Made a lot of money with that tool over the years.

A simple and cheap gizmo that will let you look at diodes and transistors and see real fast (as in 60 times a second) if the junction is any good.

Keep it safe
Jack Crow

it has both a horizontal input and a vertical input. is that the same?

**Krankshaft** · 03-11-2012, 03:35 AM

Re: Ratdude's first scope

You usually set the scope to XY mode and use Channel 1 for X and Channel 2 for Y.

**Jack Crow** · 03-11-2012, 06:39 AM

Re: Ratdude's first scope

R and K,
The gadget in the article is over complex.
Mine is 'stone ax simple' and works 99% of the time.

http://www.flickr.com/photos/9010884...57626109758650

Been trying to find the 'photos' of it in use, but they are refusing to show up at the moment.

J

Ratdude's first scope

Ratdude's first scope

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