Vintage Oscilloscope Probe Choice

[bugco]

Hello All!

This is my first post after joining your forum, and it is regarding an instrument type that I have no experience with, and it is old clunker to boot! I hope the question is not too dopey but if it is... apologies.

The unit is a Telequipment Oscilloscope Type S54
The Specs I have found state it is 10MHz Bandwidth, 400 Vdc + Max Input, Single Chanel.
Not sure if relevant but has a Y Axis selector for 1x/10x gain on panel.

It seems generally operational (?) But I have no probe, or signal generator yet.
I will only playing with this on Audio components and circuits. Low voltage stuff (no valves/tubes) until I learn a thing or two.

Question: Can I use any Probe up to the 250MHz ones I see about, or do I need to find a 10MHz unit? The lowest MHz 'cheapo' unit I have come across is 20MHz. The higher MHz probes give more choices and qualities but I am afraid they may not work at the rated MHz, and they are not 1x/10x selectable but seem fixed at 100x

Thanks for any advise/comments
Simon

[nathanpc]

Hello bugco, you can use any probe you want as long as it has an equal or higher bandwidth spec, for example the 200MHz probe will work perfectly fine on your oscilloscope. The selector switch for x1 or x10 is only used to select the type of probe you have connected, so just use the appropriate option for the type of probe you're using in order to get a accurate Y scale.

[tggzzz]

Just ensure

• the bandwidth is higher than your scope's bandwidth
• the probe's compensation range encompasses your scope's input capacitance
• with *1/*10 probes, ensure there's nobody in earshot when you notice that the switch is in the wrong position - because that will happen sometime
• the voltage rating is appropriate for your signals
• you understand the safety aspects of probing, particularly that the scope and probe shield are connected to ground

For more info on probing, see https://entertaininghacks.wordpress.com/library-2/scope-probe-reference-material/

[TheN00b]

I suggest buying whatever hertz probes you can find (higher the better) for a decent price. Make sure it has 1x and 10x on it. Marlin P Jones and Associates is where I bought my probes (not an ad) and they were Chinese, but work great after a bit of tuning and I only paid $4 per probe.

[bugco]

All great and useful comments, thank you all!, Especially the link to best 'probing' practices - thanks tggzzz, that will keep me from random searching for a while.

I must admit that I am still trying to understand why there is a 1x/10x toggle on the Scope itself... i mean do I need to set it to match the setting on the probe or if the probe is set to 10x and the Scope toggle is set to 10X is the result 1X, 10X or 100X?

[tautech]

I must admit that I am still trying to understand why there is a 1x/10x toggle on the Scope itself... i mean do I need to set it to match the setting on the probe or if the probe is set to 10x and the Scope toggle is set to 10X is the result 1X, 10X or 100X?

It's nothing to do with matching probes to the scope and only for an additional sensitivity needs but what comes with its use is more displayed noise.
Some P6100 probes will be fine for your TQ, just search the 'bay for them and you should easily find a pair for ~$15.