Re: [EE]: Transistor replacement by mike oneil .

Sean Breheny wrote: > > HI all > > My old Tek 7704A scope encountered a sudden problem last night. The display > suddenly (and permanently) shifted over to the right and compressed a > bit. After a few measurements and tests, I narrowed the problem down to > the horizontal driver board, one of the horiz diflection plates just sits > at 50V. > > As it turns out, the transistor which drives that line (marked Q95) has a > collector > emitter short. I'd love to replace it, btu I don't know what an > equivalent or suitable part would be. The original part number is > 151-0270. This is followed by the number 718 (after a space). There is > also a large letter F on the can (I guess Fairchild?). It is a PNP > transistor in a TO-5 or TO-39 can. Anybody have an idea what would be a > good replacement? Hi, I had a look at the service manual for a tek 7844 scope. Looking at the schematic for the horizontal amplifier there is a tranisisor that drives the left plate. The reference for this is Q1920. This has the tek part no of 151-0270-00 (no mention of 718). This is then described as "Transistor: Silicon, PNP, sel from 2N3495" Maybe this is of some help? Mike -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics