Crosley 9-403m Help Needed

[cdmarion]

Originally Posted by earlyfilm

OK, that is a very good clue. Use your Sam's tube pin resistance measurements and/or just trace the circuit back the B+ (or possibly B-boost) and find out where it is being lost. (Actually pull the tube first and and repower the set to see it this restores the plate voltage. This could be a simple as a shorted tube.)

If you or someone has a schematic of the video, vertical and CRT sections and could post it, it would help.

James

Ok...The first thing I did this morning was to pull the 12au7 video amp tube, as soon as I pulled the tube I got a good raster, I had previously tested the tube and it tested good but I decided to replace it with a brand new 12au7, after installing the new tube I lost the raster again. I've also noticed that with the tube removed and raster present that the bright control has no picture effect but it does act as a volume control for the audio, turn the brightness ccw and the audio volume decreases and vise versa. I'm not sure if this is a normal reaction of having the video amp removed?

I will scan the schematic and post it shortly.