Kikusui COM7101A Oscilloscope - Anyone with Service Manual? - SOLVED -

[Heatsink]

Greetings Folks,

I am a long time (sporadic) reader, this is my first post though. Recently bought this old scope, it's probably from the early 90ties. The look and feel is mostly analog, but it also has a digital mode. For 80 Dollars I am pretty pleased with it, but it does have some minor quirks, for example that the traces shift a bit when I switch from analog to storage mode.
It's not really and issue and I don't want to dive into it without a service manual. I looked around the internet and even asked Kikusui, but had no luck. Anyone by chance has the service manual?

[rvalente]

You may try to call their service support, but be ready for a long period of frustration, im two years now waiting for the schematics for a kiskusui bench power supply.

Japanese and germans have this nonsense of not sharing service information, as someone would clone them, as if they've never done this before...

[pbarton]

Your manual can be found here....https://www.kikusui.co.jp/manuals/index_e.php?MODEL=+COM7101

[Heatsink]

Thank you, the link points to the operations manual. I have it. It has some calibration information, but nothing beyond that, no schematics. I just wrote Kikusui (another) email, asking nicely for the service manual, lets' see what happens. 
 

[shakalnokturn]

The odds are that there is enough information on the manual you have.
The digital board would handle the cursors and the digital storage, so if you're experiencing shifts when switching between A/D you want to play with RV22 and RV32 (position), RV21 and RV33 (gain if needed).

[Heatsink]

Shakalnokturn, thank you for looking into this. I'll give RV22 and RV32 a careful try. I still would love to get my hands on a service manual or at least schematics though. I want to understand how signal processing is done.
I understand how an analog scope works and somewhat how a digital scope works, but this thing seems to be somewhere in between. It seems to be mostly analog with a digital add-on. Digital functions are pretty limited.

[Heatsink]

Well, after Kikusui Japan informed me that they don't support such old equipment, I asked Kikusui America Tech Support.
They emailed me a free copy of the service manual. Thanks for this great service!

[crerus75]

Now that you have the service manual, I suggest you email a copy to a site like KO4BB.com and/or the BAMA (Boat Anchor Manual Archive, bama.edebris.com).  They will place it in their service manual archive and make it available to anyone else that needs it.  BAMA already has a Kikusui category in their repository. 

[Heatsink]

I did have to sign an NDA which is valid for 1 year. Will upload it afterwards.

[shakalnokturn]

Wow! 1 year NDA on such an antique. Are they hoping you'll have lost / forgotten the manual in the meantime, given the age of the scope I don't really see what it changes if the SM goes public last year or next year...

[Heatsink]

I think it's just a formality on their side. I don't mind, I am grateful that Kikusui helped me. It is indeed a mostly analog scope, the digital part runs on two Z80 CPU's. I re-calibrated the A/D converters, but it loses calibration again when I knock on the power supply module. Next is to take it out and investigate for cold solders, bad caps, etc.


 

[shakalnokturn]

Often trimmers themselves can cause those symptoms, sometimes you can get away with contact cleaner and a little exercise, worst cases the trimmers are better replaced.