conceptual / block diagram

Hi all, I am working on an EVO MA10, with little prior experience. The sample chamber doesn't hold vacuum (despite passing a helium-spray leak check), leading to the belief that the isolation valve may be leaking and/or the ion pump is underperforming. So here's my question: Is there anywhere to be found some basic diagram of the vacuum layout of this instrument? The vacuum system doesn't appear complex, but I can't devise logical troubleshooting steps without knowing some basics. I'd even be happy for a hand-drawn sketch from someone familiar with this microscope. Just as an example: How many distinct chambers are there? I'm aware of the column and sample chamber, but is there a third? I see three vacuum connections to the microscope body. Another example: Between two of the three vacuum connections to the (column?), there is a solenoid valve. I'm puzzled over what that external valve does, when, and why, and ultimately, whether it should be included in this troubleshooting progression. SO - I'm not necessarily looking for help troubleshooting (at least not yet) but I am looking for a very basic understanding of how the vacuum system works in this instrument. Unfortunately, I can't get this info. from Zeiss OR from the user of the instrument. Any help is much appreciated, and I won't be expecting anyone here to solve my problems for me, or provide guaranteed / comprehensive / perfectly accurate service information. Cheers...