Don't panic. All fixable.

1) The second faint trace is a trigger issue. Easily remedied.
2) The multimeter needs a new fuse.

In future, please ask one question at a time.

Sorry if I seemed a bit anxious. I was just trying to give a quick rundown of the problems. I found the operating/service manual for the multimeter so I'm going to start there.

Scopes are usually out of calibration - unless it has a recent calibration sticker, its best to verify frequency and amplitude with better suited instruments.

In my workshop, the scopes are just for examining what waveforms look like.

I was thinking the same thing. But it would be nice to have the scope functioning within reasonable accuracy

 

Sorry if I seemed a bit anxious. I was just trying to give a quick rundown of the problems. I found the operating/service manual for the multimeter so I'm going to start there.



I was thinking the same thing. But it would be nice to have the scope functioning within reasonable accuracy

From time to time, various hobby magazines publish projects for scope calibrators. A master crystal oscillator and a chain of dividers is sufficient for checking sweep time.

Everyday Practical Electronics recently published a 10.0000V voltage standard. Most of the project was just tarting it up with a push button on and time delay off. The actual chip pretty much only needs a bit of board, a noise damping capacitor and a battery clip. It should be possible to verify several DMM ranges with that, then the DMM can be used to give confirmation of sinewaves on the scope.

 

Thanks Ian, I'll keep an eye out for a project regarding the sweep time. Interesting about the voltage standard, I'll have to do a search for that.

I just watched a video by w2aew on scope calibration and all that it entails so I'm looking forward to that.

I found both service manuals for the 485 and meter so I've got a lot of reading to do.

 

I just watched a video by w2aew on scope calibration and all that it entails so I'm looking forward to that.

You should have seen that the calibration procedure requires calibrating vertical at different sensitivity settings and horizontal will require checking at multiple frequencies. So you're going to need more than a very accurate 10.000V reference. You could probably cobble something together to do your own calibration, depending on how much accuracy you want. The Tek calibration procedure will likely specify things within 2-4%. The reason (IMO) being that scopes aren't meant for high accuracy voltage or time measurements.

I don't know why the 485 doesn't have a calibrator (my 466 doesn't have one either). I do most of my voltage calibration using the calibrator on my Tek 7000 series mainframes. I use my voltmeter to set the 4.0 or 400mV output (depending on scope). For horizontal calibration, I use a Tek time mark generator. I check the time mark generator accuracy by measuring with several different frequency counters and/or comparing with some frequency synthesizers I consider to be accurate enough for my requirements.

One good thing, though YMMV, is that the scope may not need any, or major, calibration. I checked my 466 recently and it was spot on; even though it was last calibrated in 2005.

Just make sure you let your equipment warm up for a couple hours before checking...

 

Thanks Ian, I'll keep an eye out for a project regarding the sweep time. Interesting about the voltage standard, I'll have to do a search for that.

It could take a while to find the article to give you the exact chip number, but I believe it was an AD part - just get their page and look for voltage standards.

It doesn't take all that much Googling to find crystal oscillator circuits that can drive TTL, the old favourite divide 10 chips were the 7490 but they've got rare as rocking horse............... There's a newer part that contains 2 of the required decade counters in one package, can't remember if its the 74290 or 390, but there's somewhere near the right ballpark.

Not sure whether there's a similar enough CMOS decade counter - the 4017 is listed as a decade counter although every one of the outputs produces in sequence, a single pulse for every 10 clock pulses, but if you're happy with that as a time sweep time standard; CMOS gives a cleaner squarewave, and if you use unbuffered type Vdd can be more than 5V.

The TTL 7490 and descendents are binary coded decimal decade counters, in the standard configuration for driving a display decoder-driver, the 1/10 F-in output (output D ) isn't 50:50. The input is an uncommited flip-flop that simply divides by 2 - and also outputs 50:50 mark space ratio, if you simply move that from the input of the divider and drive it from the D output, you still get /10 but with 50:50 MSR.

 

It could take a while to find the article to give you the exact chip number, but I believe it was an AD part - just get their page and look for voltage standards.

I found the article. The part number is AD587KNZ. Digikey has some available for $8.41.

Here is the article in case anyone is interested, it starts on pg. 10:
http://mint.re/Magazines/May 2015/Everyday Practical Electronics - May 2015 UK.pdf

 

I found the article. The part number is AD587KNZ. Digikey has some available for $8.41.

Here is the article in case anyone is interested, it starts on pg. 10:
http://mint.re/Magazines/May 2015/Everyday Practical Electronics - May 2015 UK.pdf

In the EPE project article, there was mention of various type number suffix letters - one of them is the economy model at a lower price.