I recently picked up a 199B with a bunch of test leads and an i2000 Flex high current probe for a nice price. The battery is completely hosed, but after letting it sit on the charger for a bit I was able to get it powered on, though it dies the second the AC adapter is pulled.
The DMM inputs seem to work fine (just tested off of a 9v battery that was handy) but both the "A" and "B" channels of the scope are non-responsive.
Could this be from the low battery? Or is it pretty safe to say there is a board issue with the RF inputs?
My inkling is to return it ASAP and get a refund, but if there's a possibility that it's due to the low battery, maybe it's worth gambling $35 on a new one before giving up on it.