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peter_scott · 19th May 2017, 4:46 pm

Mine looks as below but Jac on this forum managed to get rather better results than I did. You'll see in my web page if you click on the test card image that I didn't manage better than 2.5MHz when fed from Aurora but Jac has very nice 3MHz. Having said that when I send it a 405 line signal with Test Card C using the PC and graphics card I can register a bit of 3MHz although you'll note that due to the crude sync combiner that I'm currently using there is no interlace.

I found I could achieve better response with a little hand and eye test card tweaking after adjustment of the response curve.

I removed the "optional" push about coil because it messed my focus and picture centring was easily achieved simply by pushing the tube neck back and forth.

The speaker will be very low resistance but a scope would tell you if it is shorting the output.

Peter

19th May 2017, 4:46 pm	#51
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,274	Re: Marconi 702 advice Mine looks as below but Jac on this forum managed to get rather better results than I did. You'll see in my web page if you click on the test card image that I didn't manage better than 2.5MHz when fed from Aurora but Jac has very nice 3MHz. Having said that when I send it a 405 line signal with Test Card C using the PC and graphics card I can register a bit of 3MHz although you'll note that due to the crude sync combiner that I'm currently using there is no interlace. I found I could achieve better response with a little hand and eye test card tweaking after adjustment of the response curve. I removed the "optional" push about coil because it messed my focus and picture centring was easily achieved simply by pushing the tube neck back and forth. The speaker will be very low resistance but a scope would tell you if it is shorting the output. Peter Attached Thumbnails __________________ http://www.nostalgiatech.co.uk https://www.youtube.com/c/PeterScott/videos Last edited by peter_scott; 19th May 2017 at 4:59 pm.