Hi, I finally got one Tektronix P5205A probe, but I don't have a way to make the adapter board.
Instead, I planed to make an external power supply and connect it to the bnc box of Tektronix probe.
I opened the BNC box of probe and found that it connects only to +- 15Vdc sources and data pins. All other pins have no connection on circuit board.
Please, I would really appreciate to have any confirmation about my draws bellow, as I infered them from the pictures above (mainly the first board and the probe hooked to it), and the probe costs 10x my oscilloscope!
Highlights (from the post bellow):
- I have identified that the Black and Blue wires are the -+15V main power supplies. When the -+15V are on, I can hear a brief beep and LED flash.
- The official power supply 1103 also supplies +-5V. But they are not likely used in p5205, since p5205 has a circuitry to split/convert the +-15V supplies to a pair of +-5V supplies.
- Brown goes to the Tekprobe "Data" pin, which is the attenuation sense input (aka "readout" pin).
Red goes to the center wiper of a 1-turn 10k pot, and the ends of the pot go to +15 and -15. This is the offset adjustment accessible through the small hole in the compensation box
You are correct on the blue +15V and black -15v.
...power supply is not demanding. Mine draws 71mA steady.
.. So, 50 ohm termination with this probe is not a good thing.
Now, there are two important questions: 1). Will the power be clean enough at the required load level; and 2). The P5205 was speced to use +/-15.0V power. Will a +/-10.5V supply be adequate?
Answer: A sine signal of 100MHz and Vpp of a couple volts was connected to the input of the 5205.
For supply changing from 15.0V to 9.0V, the signal output stayed flat at about 2.6V. When supply further reduced to 8.0V, the signal output was dropped to 2.45V, or a 0.5dB attenuation.
...When the supply further dropped to 9.0V, the output voltage clamped about 7% and other artifacts started to show up at the peaks of the waveform .
Based on these tests, I think a supply voltage between 10V to 15V should work fine.
The case (main case, not the BNC connector case) is fastened with four screws. You can access the screws by lifting the top plastic sticky sheet cover. You need only to lift it at each corner just enough to see the screw well. A sharp knife can be used to do the initial lifting.
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