General > Buy/Sell/Wanted

For sale: HP 1152A Active scope probe - 2.4GHz bandwidth - 0.7 pF

(1/2) > >>

tnt:
Hi,

I have two of the scope probes and only really need one.

I modified one of them to work with the newer 3000-X agilent scope and it seems to work great. The mod only involves the 'comp box' and not the high speed probe head.

Depending on what you prefer I can sell either:
 - A unmodified probe (exactly as I got it) that has no visible tampering / damage (and still has the warranty seal) but that I can't test (because not supported by the 3000-X)
 - A modded probe that I can test and that will work in the 3000-X (and any other).

Both have most of the accessories (not all but close) and spare tips.

I'l try to post some shot of the probes and accessories and of the one working with the 3000-X.

Make offer (here or in PM).

Cheers,

    Sylvain

ErnieEngineer:
Hey, how did you get the smartprobe to work with your scope? whats the hack?

tnt:
There are several things:

Identification

Old probes identified by a specific resistor value between a pin and ground. Now, they all have the same resistor value but have an I2C EEPROM for the probe specs. So you need to replace the ID resistor and add an I2C EEPROM.


Power supply

More advanced scope have a variable symmetric power supply sent to the probe. Between +-3V to +-6V depending on another set resistor. The 3000-X doesn't have this supply and only sent a fixed +- 5V value, which is the value required by all new modern probes. Unfortunately the 1152A wants 4V so if you just try to plug it, you send 20% too much voltage to the delicate FET amplifier in the probe ...

Solution is to cut this 5V direct path and insert a LDO + filtering in the path.

Pictures in attachement. The orange stuff is a kapton sleeve I made to ensure no shorts.

Cheers,

    Sylvain

ErnieEngineer:
thanks tnt. you cam thru for me again! how did you figure out the probes use a chip id? did you have a newer probe to mess around with?

never mind. i see you posed all about this in the projects section

tnt:
Do you have a 1152A ?

Navigation

[0] Message Index

[#] Next page