I have two large fold out schematics of Heathkit Model IO-103 oscilloscope. Send a 9 X 12 SASE and one will be yours. 73 Bill W4MA 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"