Some advice on purchasing a (local) oscilloscope

[ethereal]

Hello everyone,

I'm just starting out in the world of actual hands-on electronics after having spent the last six months reading things on the topic and talking to some EE friends. I've just put in an order of the parts that I think I'll need for my first two projects (so when I have to wait for the 3-week PCB manufacturing turnaround, I still have something to work on!) and am now turning my attention to the various things that I'll need to build and debug things. I'd quite appreciate some advice from more seasoned individuals.

I have a decent (temperature-controlled) soldering iron bought off of one of the aforementioned EE friends. (It's apparently not the best iron, but "gets the job done" is what I've been told. Reserving judgement until I use it for a while). I have a power supply made out of an old computer ATX power supply, a (cheap) multi-meter, and all the rest of the usual suspects. The two important omissions from my workbench are an oscilloscope and a logic analyser. I'm mostly concerned with the oscilloscope right now, for reasons I'll get to in a moment...

I've been doing some reading on the subject. The circuits I'll be working on first are running with a 24MHz digital signal, but I have some preliminary designs for upgraded versions running at 64MHz, so I'd like to be able to use an oscilloscope on circuits at similar frequencies. I was thinking about getting a 200MHz scope for that reason (so I can get the third harmonic on a 64MHz signal), but as I'm planning on using LVDS links, I think I'd really find a use for more than just two channels. As a result, I was thinking about getting a Hantek DSO5062B (maybe the extended memory version) and using the wonderful hack by tinhead. (My day job is messing around with software internals to make things break, so I'm quite happy with executing that hack.)

However, I recently noticed that someone near me is selling a HP 54600B scope for $60. It's a 2-channel, 100MHz scope from the early 1990s; as a result it doesn't have any sort of fancy functionality, but it's close by and extremely cheap. (I live in Canada, so shipping from US distributors is often extremely expensive, disproportionately so considering the additional difference for EU shipping!) Furthermore, someone else is selling a Phillips PM3320 that's a 200MHz, 250MSPS 'scope for $80. Both scopes apparently work well.

Given that I'll mostly be working on digital circuits at frequencies around 50MHz . . . in your opinion (humble or otherwise), is it worth purchasing either? Is it the sort of thing that I might find useful, given that I'm already likely to purchase a logic analyser separately?

Thanks!

- ethereal

[xwarp]

I'd get the Phillips.

[ethereal]

Some more information about the Phillips (found the service manual, woo!):

• Service manual is from 1987. I'd assume the scope is from the same era, late eighties.
• It's a 10-bit scope.
• There are four storage registers, capable of storing 4,096 samples each. Full memory only usable down to 1ms/div; 500us/div and below are max. 512 samples.
• Looks like only linear interpolation between samples is available.
• It weighs 18kg (I knew scopes were heavy, but . . . wow.)
• Full schematics are included! Seems useful for repair etc.

[marshallh]

The 54600B has one of the best UIs and responsiveness of any digital scope ever made. They do the screen refresh in hardware, with a precursor to current Agilent's Megazoom technology.

The 100mhz scope will let you know if something is horribly wrong. If you want to do proper SI analysis you will need 1 ghz scope as a starter for digital stuff. But until you are more committed don't bother, just get the 100mhz