Hi,
I am taking at look at an old Bell & Howell School oscilloscope marked as "Solid State Oscilloscope Triggered Sweep 5MHz Bandwidth" it is the blue one that is a little taller than it is wide.
Also known as:
Heath Model # 100-203-31
Bell & Howell # Model 9560-1
5 Inch Triggered Sweep Oscilloscope
Some docs here. I plan on assembling those into a PDF:
www.bunkerofdoom.com/lit/bellandhowell/index.htmlHere is the PDF... The owner of Bunkerofdoom said to make it into a PDF was OK with him.
http://meanmutha.com/BellHowellScopeManual.pdfWill post pics tomorrow.
I got it generally up and running. Was way out of cal and you couldn't find a trace at all. But I went through the cal procedures and it is generally OK now.
I am having an odd issue, though. When I set the horizontal division (uSec/cm) to 1 (the lowest setting) I am unable to trigger on a signal from about 80-120kHz. It will not get a stable trace even if you turn up the Stability control (need to research exactly what that is, as I am used to Tek scopes, which have no such control). I will not trigger with internal or external triggers in that frequency range. But only if the horizontal is set to 1uSec/cm.
I tried two function gens, and with and without termination. I tried sine, square and triangle waves. It just won't get a good trigger.
My wild guess is this is some ripple on the power supply. I am seeing a fair amount when measuring with an AC meter. I had around 1V on one rail, and half a volt on the other, etc. I think I should replace the old electrolytic caps, and measure any resistors I can (lots of carbon composition).
Does anyone have a working one of these scopes? Would love to get some measurements. The docs have some voltage measurements, but no ripple tolerances like a Tek manual (professional tools vs. something you build in school).
Interesting little scope, really. It was a kit to be built by students and then used. They do this after they build their own Bell & Howell Nixie tube meter (got that in the sale too!). Both kits are made by Heath. I was planning on giving this to a friend who is new to scopes if I can get it going.
Thanks. Any info is appreciated.