David:
http://www.webtfg.com/sync7.htm
The above link is to The Film Group and their "Blooper Hand-Held Slating Unit".
It's been a couple years since I talked to 'TFG' and that was about crystal sync work. I am not up to speed on their current offerings but it's worth a call.
Good luck.
Were batteries in the cameras during long term storage? Any damage in the battery compartments from leaking batteries? A compromised ground connection may be causing problems/damage to the CdS photocell.
Harry, do you have operations manuals for your cameras? They were designed to use alkaline batteries. Are both of your cameras loaded with alkaline batteries?