Sharp CE-150 printer/cassette interface questions

[polbit]

There doesn't appear to be any English-based forums for these, so I hope I'm not overusing HP museum forums with all these Sharp questions...

I have purchased few of these to work on, and all behave the same way (after removing the old NiCad pack), with a 1.5A 9V charger:

- When I turn on my Sharp PC-1500, the printer head moves back and forth few times, then I get the Check 6 error. That's a battery error. It won't accept LPRINT - Error 78 - again battery error.

- The paper advance button does nothing. In fact I can't make it move other than the head - no pen change mode, etc.

- The cassette interface works fine.

Do I need to replace the battery to make the printer work at all, or do all have the gears broken?

As far as the battery, other than trying to solder 5 AA Nimh cells, has anyone found a pre-made pack in the 3-2 shape?