Looking for tektronix probes with the extra pin that lights up the 10x range

[imaradiostar]

Any clue how to identify them? I guess I can look carefully at pictures on ebay but surely someone is selling aftermarket ones for way less somewhere.

jamie

[loudthud]

Tek probes use a resistor between ground and that extra little pin to tell the scope what the attenuation factor is. Not likely to see that on an after market probe. The Tek probes with that feature have the plastic shroud over the BNC connector, I don't know of any exceptions.

A word of caution: Tek probes are modular and some of the ones you find on ebay have mis-matched parts. The tip assembly, cable and "comp box" usually won't work properly if one of the parts came from a different model probe. Example: A 1 meter probe won't compensate properly if a 3 meter cable is substituted. So buyer beware. Some sellers either don't know or don't care.

[imaradiostar]

Thanks for the tips! I think I'll just buy more cheap probes like the ones I have. If the 10x thing really bugs me I can always pull out the channel modules and install a little "10x illum" switch.

I don't need particularly great probes. I don't ever work on RF stuff with my scope and rarely see frequencies above 20k. I've only seen them while working on the occasional switcher. I have proper scopes and probes at work if I need higher frequency tools.

jamie

[Enzo]

I have always gotten just fine performance in my audio work with the basic cheap $30 probes you can get anywhere.

[imaradiostar]

I've been tasked with upgrading a bunch of hardware at work and I found a few worn out 10x probes in a box at work and they said I could have them- score! Not perfect but serviceable.

jamie

[Tom Phillips]

If the 10x thing really bugs me I can always pull out the channel modules and install a little "10x illum" switch

Jamie,
If you goal is just to activate the 10X light then I may have an easy solution for you. Following is a method I use with my Tek 456 & 465B scopes. Then a disclaimer.

Solution: I slipped a thin split lock washer between the channel input BNC receptacle and plug. I found the unusually thin split lock in my box of misc. switch hardware and bent it open just the right amount to short the switching terminals on the scope when the BNC plug is connected. I use this where my load box is pretty much permanently connected to one of my scope inputs because I have a 10X attenuator permanently installed in the load box monitor output.

Disclaimer: As Loudthud mentioned there is a resistor in the Tek prob plug between the switching pin and ground. In my Tek 6109 probe it measures 11 kΩ. However, using the dead short washer on my personal Tek scopes (465s & 456Bs) has caused no problems and I’ve been doing it for over 10 years. The probe switching contacts in these models do not directly control the lamp (or LED in the case of the 465B). It just grounds the base of a darlington transistor though a total of 1.6 kΩ of internal resistance.

Cheers,
Tom

[imaradiostar]

another good tip- I'll have to try that too.

jamie