Rigol DS1102E showing negative signals on Channel 1

[interconnect]

I recently got a Rigol DS1102E that my work was getting rid of.  Channel 1 has some sort of issue where the signals are negative when they should be positive.  The issue is only with Channel 1; Channel 2 appears to be Ok.  I've tried swapping scope leads, so that's definitely not the issue.  I see the same issue no matter the signal; they are always very low and negative.  I have also tried doing a factory reset and the self-calibration procedure, but no luck there.  I have attached a couple photos of Channel 1 versus Channel 2 using the built-in calibration signal generator. 

Anyone know what may be going on with it?  A bad amplifier or something?  I think it may be some sort of hardware issue.  Has anyone seen this before or know what may be going on here?

[wasedadoc]

Why do you say that CH1 is low? Photos show it is about five times larger than CH2.

What are the probe attenuation factors set to in the scope menu? Those must be manually set to match the little switches on the probes.

[interconnect]

I guess I meant it’s low in that it’s negative, when it should be positive. Scope and probes are both set to 1X.

[807]

Are you absolutely sure that the probe setting is set to 1X in the channel 1 scope menu? You would get that p-p reading if it was set to 5X. Not sure why it has a negative offset though.

What display do you get if you press the "Auto" button.

[2N3055]

This scope have a setting in channel setting to Invert channel. Did you check if that is reason?

[interconnect]

This scope have a setting in channel setting to Invert channel. Did you check if that is reason?

Yes, I did check that. Invert for both channels is off.

[interconnect]

Just found that I am getting -17.2VDC on Channel 1 with nothing even hooked up!