[Heathkit] Need IM-16 Solid State Voltmeter Info

[jack m]

Hi Gang,
 
I just came into possession of an IM-16 Solid State Voltmeter which has been partially bubba-butchered internally - someone actually replaced the power transformer and battery with 2 wall warts (internal to the cabinet and rattling around!) - one 7.5 volt AC bucked with or against a radio shark universal transformer,  and a 1.5 DC wallwart tied to the battery terminals for the ohmeter function, and they even modified the circuit board to do all this!  Maybe not a bad idea, but I'd like to return it to original, since it's complete, and the case, meter, panel, 2-way probe and knobs are all pretty nice and original.
 
Does anyone on this list have an e-copy of the manual?  I'd like to get the parts list, board x-rays and whatever instructions I can find.  I assume the original power transformer was about 10-18 volts AC since there is a 9-volt battery plug inside for battery operation, and I did trace to what appears to be a zener diode right on the transformer secondary and after a half-wave rectifier.  Thre are also some mysterious traces and lands under the transformer mounting, which may be used (originally) for a 115/230 VAC selection using a dual-winding transformer primary.
 
Thanks 
 
Jack