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Forum 141

[Closed] 1982 Philips LaserVision VLP-600

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Video Recorders, CED, LaserVision, DVD & DTV

Last Post by crustytv 5 years ago

41 Posts

9 Users

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crustytv

(@crustytv)

Posts: 11869

Vrat Founder Admin

Topic starter

Hi Rich,

Yes the waveform I got completely threw me too, I was expecting a square wave as shown on the cct. Now I don't know If I have a intermittent fault or my test connection was at fault but after seeing your results I removed the connection to TS7411 checked it was on the collector (it was) and then put it back. I then powered up fed in the 150Hz 1Vpp Ramp and low and behold I have the square wave output and the mark-space changes as I move up the frequency range. Three snapshots below 150Hz, 450Hz and 750Hz. So the pulse from IC7408 is behaving correctly, it looks like the mono-stable is also working so my fault has to be elsewhere, the problem still remains though...... where!