From nntp.crl.com!howland.reston.ans.net!ix.netcom.com!netnews Sat Oct 28 07:44:42 1995
Path: nntp.crl.com!howland.reston.ans.net!ix.netcom.com!netnews
From: expert_e@ix.netcom.com (David Roberts )
Newsgroups: rec.video.cable-tv
Subject: Re: external black box descrambler
Date: 27 Oct 1995 04:03:06 GMT
Organization: Netcom
Lines: 56
Message-ID: <46pllq$50f@ixnews7.ix.netcom.com>
References: <46nvek$302@news.uncc.edu>
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X-NETCOM-Date: Thu Oct 26  9:03:06 PM PDT 1995

In <46nvek$302@news.uncc.edu> kcwinter@uncc.edu (Kevin C Winters)
writes: 
>
>I've got a SA 5890 box and I'd like to get all of the premium channels
>descrambled.  I'm not interested in opening up my box and replacing
>the existing chip with a test chip, although I'm told it _can_ be
>done. What I'd like to know is, how can I incorporate the test chip
>into an external device (black box) to reprogram/descramble my box.
>
>Before someone says 'it can't be done,' let me say that I've seen such
>a device.  The kid who built it wouldn't tell me much about it (mainly
>because he has a lucrative business "zapping" boxes), but he did open
>it up and let me see inside.  It's a breadboard with a chip and a
>resistor. Of course, I couldn't see the bottom of the board and the
>wires and connections there.  BTW, his device only works on Zenith
>boxes.
>
First off, did you mean SA8590, not 5890? Assuming so, the 8590 can
theoretically be zapped one of 3 ways:

   a. An intelligent "cube" to simulate VBI command data.
   b. Replacing the micro-processor.
   c. Adding a "test kit" the writes over the serial EEPROM's, loading
      data that activates the box.

It is my opinion that it is not possible to do option A on this
particular model. Sending command data on top of real video coming in
from the cable company sounds very difficult and expensive; I doubt
anyone is doing it with any practical marketablity.

As for the Zenith box, your talking apples and oranges. It's not
logical that just because one brand can be done a certain way that
"any" brand can also be done. The device your "friend" showed you
sounds like a standard replacement PROM (some companies use PAL's
though), that is hardwired into the CPU of the ST-1000 and ST-1600
boxes. If I'm correct, it is NOT external to be box but seriously wired
internal. (Typically, it is a replacement PROM for an epoxyed covered
unit, and is connected with 3 additional wires.) You did'nt describe
enough hardware to account for a device that has a power supply,
generates a digital data stream, syncronizes it to the incoming video,
and merges it to the picture info (with an RF modulator to boot!).

A quick example on how "zapping" can vary model to model, never mind
brand to brand.

- A Scientific Atlanta 8550 and be zapped (once activated) with simply
ONE diode.

- A Scientific Atlanta 8580 CANNOT be zapped with a diode, but CAN be
zapped with an inexpensive FSK generator.

- A Scientific Atlanta 8570 CANNOT be zapped with a diode OR an FSK
generator, but can only be zapped by an serial EEPROM writer or
replacement CPU.

Be careful who you listen to. Not everyone is an expert...