(IMG:Thurlby_1503_1.jpg)(IMG:Thurlby_1503_2.jpg)(IMG:Thurlby_1503_3.jpg) Service Manual - (https://k1.spdns.de/Vintage/Sinclair/Other%20Inventions/Other%20Electronics%20Products/SINCLAIR%20THURLBY%201503%2C%201504%20MULTIMETER%20SERVICE.pdf)