Joe Try Intrenational Crystal Manufacturing in OK (www.icmfg.com) They have formulas available for most Heath gear. Thanks Dom Listserver Subscription:listserv at listserv.tempe.gov - "subscribe heath 'name' 'call'" Listserver Submissions: heath at listserv.tempe.gov Listserver Unsubscribe: listserv at listserv.tempe.gov - -"signoff heath"