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It's scope week - Printable Version

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It's scope week - Radioroslyn - 05-18-2017

at Radioroslyn. Since Mike got my dad's old Tek 465 up and running I thought I'd have a go at my old Heathkit HO-10.
It's designed to be used a as signal monitor scope in a ham station vintage about 1963. Haven't used it in 15yrs or so. Flipped it on a while back and it had no trace. This preciptated a rebuild of the power supply. Now if I had longer arms to reach into my deep pocket I could order a capacitor kit from Hayseed Hamfest @ $60. But I don't so I rebuilt a can to fit it. Back in the 60's you could easily get HV electrolytic cap in a wide variety of voltages. Now days it's pretty much 160,250,and 450v.
Had to use a slightly taller can as all of the replacement were 450v (3-22mf and 1-33mf) and a couple of 40mf @ 350v wired in on the chassis. Along with these there is also a pair of .15mf@ 1.5kv (HV filters for the crt anode voltage). Used 3 .68@ 630v to get about .2@1890v. A common issue with these scopes is that the .15mf cap will short and take the 1550v winding on the power transformer. That pretty much renders it scrap.
Got all of that replaced and found a few problems, couple of resistor way out and a broken wire of two. After that power it up and it was back to normal. Tweaked the CRT a bit so the trace was straight.
Manual is here  http://www.rsp-italy.it/Electronics/Kits/_contents/Heathkit/Kits/Heathkit%20HO-10%20monitor%20scope.pdf
It's really a bare bone scope but does have some handy features like a tone generator that you can hook into your transmitter audio to check for distortion and level of modulation. Can be used to monitor radio signal though a receivers IF stage. Want to give that a try with the old HRO set.
Pictures @11pm.

RE: It's scope week - Radioroslyn - 05-18-2017

More pics including a John E Fast 2.0mf cap that I need to source. I have a 630v one but I have to use it in a 200v circuit. Novel name I thought.

RE: It's scope week - morzh - 05-18-2017

That Tek your dad's? That's like 70s model.....

RE: It's scope week - Radioroslyn - 05-18-2017

Dad worked for Motorola starting in the late 60's and retired from there in the 90's. I'd guess the Tek was a perk and probably wasn't used much. He was designing VHF/UHF radio systems for two way radio accounts (like police and fire) making sure that they would fulfill the sells claims. He was in his mid 40's when it was built.

RE: It's scope week - WallaceRoger - 05-19-2017

Someday I want to learn how to use one of these. When I was a night shift janitor in college I always saw these in the electrical engineering labs and thought they were really cool. Icon_smile

RE: It's scope week - morzh - 05-19-2017

Using scopes is simple, they merely provide for graphic representation of the waveshape of signal. One simply connects it go the signal and then watches it. Usually the user knows what general shape to expect and so sets up the vertical (V/div) and horizontal (time scale, sec/div) scales accordingly.
The gist is in understanding what the waveshape means. And that goes way beyond the usage of scopes.

Same goes for every measuring device: a DMM, an EKG, MRI, etc. This is why learning basics is to me way more important than learning tools.

RE: It's scope week - Eliot Ness - 05-19-2017

(05-18-2017, 09:41 PM)morzh Wrote:  That Tek your dad's? That's like 70s model.....

I was told by a radio collector and employee (of Tektronix) that the 465 was their best selling scope.  I could believe that since everyone I knew in the 70's and 80's was toting around a 465.  As much as I liked that scope it seemed like every calibration cycle my 465 had at least one issue.

RE: It's scope week - morzh - 05-19-2017

Seems like a nice enough unit. Plus easily taken apart and all the transistors are socketed, makes for easy repairs.

RE: It's scope week - Radioroslyn - 05-19-2017

Hi Greg,
You might like to have a look at this vid. Done by a Tek employee about using scopes to troubleshoot and how to set them up. Unfortunately it was done on the fly so some of the recording techniques aren't the greatest. Never the less has  a lot of useful information.
https://www.youtube.com/watch?v=niBGkqlh2XY

RE: It's scope week - WallaceRoger - 05-20-2017

Thanks Terry, I will watch that!