Needed Service Manual of Kikusui ORC11 Oscillator

[sryun]

I bought a used one, Kikusui ORC11 oscillator a year ago. (1st image)

But recently I had some dissatisfaction with its quality of square wave.
Following figure is a square wave at 500kHz and it looks like there are a lot of distortion, not strict square form. (2nd image)

At -50dB output level, it looks like some oscillation waves are mixed in main wave. (3rd wave)

I feel it needs some repairs or change of some devices (electrolyte capacitors etc.).
But I could not find a serve manual or schematics in the internet, so is there anybody who gives some help to me?

 

[thaumaturge]

You might try these contacts directly to see if they can help, but your model doesn't register a response from either site. kikusui@kikusuiamerica.com, service@kikusui.co.jp

I see your output has a BNC connector. Do you have the proper termination on the cable?
If generator is expecting a 50 ohm load it will make a BIG difference.
Doc

 

[cliffyk]

The ORC-11 rise time spec for square (pulse) wave output is 200 ns or less.

from the ORC-11 owners manual:

Here is a trace from my well-calibrated ORC-11 (I have the service manual which cost $65, and also a very specific non-disclosure agreement):

This was captured with a Lecroy 9354L 500 Mhz scope, with a 600Ω termination into the 'scope's 1 MΩ inout. You will note that the waveform is very similar to that which you captured, and that the rise time is 166.6 ns well meeting the published specification.

The square wave output on this instrument is sort of a "freebie", something they provided along with the very low distortion sine wave output--calibrated, at 1 kHz, my ORC-11 output has a THD + N level of 0.0019%--raw, unfiltered. Applying a 30 kHz filter drops that to 0.0011%...