IF SH doesn't have one available, you might try Bulldog Battery 800-721-1119 in
Ohio, or The Nicad Lady (CA?) to
rebuild the NiCd tray. Bulldog probably can
rebuild it using modern 2000-3000mA
batteries to give you 3x-4x longer run times, and genearlly you can rebuild with NiMh cells. The only downside is that
charging the new pack will take 3x-4x longer as well, unless you also replace the
charger.