If the on-wait-off-quickly-back-on sequence works, then the battery is no good.
Then I'd check to make sure the AV card and the adapter are both seated firmly.
Also, I forget if the 6100 has a motherboard reset button, but if so, you should press that for 60 seconds after adding new hardware.
Any way you could try the motherboard video? ie do you have an Applevision monitor or adapter? Is it possible to confirm the AV card in another x100 machine, or substitute a different AV/HPV card? Ditto on the adapter. Are you completely sure it's not a DOS card adapter?
Don't give up. Sometimes it just takes a while to get these old beasts going again.
Then I'd check to make sure the AV card and the adapter are both seated firmly.
Also, I forget if the 6100 has a motherboard reset button, but if so, you should press that for 60 seconds after adding new hardware.
Any way you could try the motherboard video? ie do you have an Applevision monitor or adapter? Is it possible to confirm the AV card in another x100 machine, or substitute a different AV/HPV card? Ditto on the adapter. Are you completely sure it's not a DOS card adapter?
Don't give up. Sometimes it just takes a while to get these old beasts going again.