Does anyone have a Philips PM3240 Oscilloscope and know how to calibrate it as I can’t find a sqaure wave.?

I recently brought a used Philips PM3240 Oscilloscope off ebay for £16, but I don’t know how to calibrate it as even though I have found instructions for it online, it does not really detail how to calibrate it. It doesn’t mention a built in square wave anywhere nor can I see a button or picture for a Square wave on the oscilloscope, so I assume it doesn’t have one. Does anyone else have one and know how to calibrate it?

Okay, check out:

http://www.cpc.wmin.ac.uk/~delaitt/PM3240/circuit.jpg

and

http://www.diybanter.com/showthread.php?t=44691

It appears that your scope does have a square wave generator built into it for the purpose of calibration.

My guess is that there is a tiny external terminal some place on the face of the scope for this purpose. It may not be real obvious at first and you may be just over looking it. But it’s there.

Heathkit Oscilloscope Model # IO-4555 for sale on Ebay