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Article #658Re: advice on descrambler
From: Mark Robert Thorson
Date: Thu, 22 Jun 1989 00:29
Date: Thu, 22 Jun 1989 00:29
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1960 bytes
I once built a descrambler with no components except an SPDT switch! Several years ago, channel 26 in San Francisco was broadcasting scrambled transmissions in which the horizontal sync pulse was inverted. I opened up my set, and found a single pc trace going from the video amp section to the horizontal sweep section. I cut this trace and hooked up the input to the horz sweep to the pole of the switch. I hooked one side of the switch to the signal from the video amp section. The other side of the switch was hooked to a signal I found by experiment. First, I hooked it to the other side of the same transistor which generated the signal going to the "normal" side of the switch. Didn't work. Then, I traced the base input to that transistor back to another transistor in the video section. My first connection there didn't do anything, either. Then, I moved the connection to the other side of that same transistor. Bingo! I had found an inverted form of the video signal, and it worked just fine for receiving the scrambled transmissions. I still couldn't get the sound, because it was scrambled in some obscure fashion, but that really didn't matter, because channel 26 only broadcasted pornography :-) BTW, this can be dangerous. My set was isolated from the line by a transformer. Don't assume that because I lived to tell this story, that you will too. [copyright 1989 Mark Thorson; all uses of this document are allowed, except for republication in moderated new services, such as that provided by Anterior Technology.]
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arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!uunet!portal!cup.portal.com!mmmReferences:
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!uunet!portal!cup.portal.com!mmm From: mmm@cup.portal.com (Mark Robert Thorson) Newsgroups: sci.electronics Subject: Re: advice on descrambler Message-ID: <19744@cup.portal.com> Date: 22 Jun 89 00:29:51 GMT References: <111377@sun.Eng.Sun.COM> Organization: The Portal System (TM) Lines: 30