About 8 months ago I bought Tamron 28-300mm Ef mount zoom, 2nd hand from Ebay. It worked fine for 4 months and it then started to show the ER reading. Over the next month this error message became more prevalent and now I find I cannot use it beyond 100mm. I spoke with a repair technician who advised that it was an aperture fault with the wiring connections and the lens would have to be completely disassembled for repair. From internet searching I found a temporary solution was to tape over the brass contacts and the lens would work in manual focus mode ok. Could someone point me in the direction of a diagram that explains what the 7 brass contacts on the lens mean? My lens from right to left a small brass square, a brass rectangle the contacts rise to another level closer to the camera body then 5 other square brass contacts. I was considering taping over the contact that controls aperture and use the lens in TV or manual mode. Can anyone help.