Unauthorised Access UK  0636-708063  10pm-7am  12oo/24oo

From    : G8VHF @ GB7CRG.#11.GBR.EU

To      : ALL @ GBR

Date    : 920219/1744

Msgid   : BF 23085@GB7CRG, 35535@GB7EDN $23085GB7CRG

Subject : SKY DECODER MOD - DETAILS

Path    : GB7SAN!GB7JED!GB7NCL!GB7EYM!GB7YAX!GB7CHS!GB7CRG


     About four weeks ago I put a bulletin out asking if anybody 
had the details of how to modify the external SKY decoder to
stop SKY from "zapping" cards. I had many many replies, mostly 
from people wanting the mod, but a couple  answer to my question 
also arrived.

     The details supplied were a bit sketchy, but thanks to G6WZD 
the modification was finally completed and the unit is back 
together with hopefully an ever lasting card. I promised to send 
details of the mod to ALL@GBR so here are the details of what I 
did to my unit. If you have the modification to the internal 
decoder can you please pass it on.

73's and many thanks to those who help... John G8VHF @ GB7CRG     
 




               SKY VIDEOCRYPT DECODER MODIFICATION  
               

     The following notes detail how to modify the SKY external 
decoder to disable the re-programming part of the circuit 
thus stop the "zapping" of the card that makes it invalid. It 
should be noted that this modification will probably also stop 
the card from be updated and making other channels available to 
the viewer. I'm sorry to say that I cant even guarantee that the 
modification does what it claims to do, but I have been assured 
by several people it does work!!. So in theory if you have a 
valid SKY Movies+ or Movie Channel card then it should stop valid 
just as long as SKY dont issue a whole set of new cards to 
subscribers or issue an unknown-command to the decoder.

     Just one other point. You do this modification at your own 
risk, and no way can I be held responsible for the failure of any 
decoder or card. I was originally sent two mods that simply did 
not work on my system and produced the message "invalid card" 
from my decoder. The third modification did work but I have added 
a couple of more bits to aid further protection to the decoder 
itself.             


     Below is the circuit diagram of what you have to do to 
disable the re-programming part of the decoder. It involves 
isolating pins 38, 37, 36, and 35 of the 8252 microprocessor and 
connecting a zener diode from J108 to earth. You also need to 
solder together a number of components a connect a new 5 volt 
feed to them.



   J130
5 VOLT FEED
     !
     !   IN4001+
     +---OOOOOOO--------+
               +        !
                        !    LIFT HERE
 RP15   -------OOOOOOO--+----   X------ PIN 38  }
                        !                       } 
 DP24   -------OOOOOOO--+----   X------ PIN 37  } CPU IC
                        !                       }
 DP25   -------OOOOOOO--+----   X------ PIN 36  } 8252
                        !                       }
 DP27   -------OOOOOOO--+----   X------ PIN 35  }
                       
 DP26   -------OOOOOOO----------------- LEAVE ALONE

                 47R
 J108   -------OOOOOOO--------+--------
                              !
                              !       15V ZENER
                              +--------OOOOOOOO------+
                                       +             !
                                                     !
                                                     !
                                                   GROUND
                                                    J120



     Start by taking apart the decoder, turn the front to you and 
look at the bottom left hand side near to the power supply 
heat sink. You should then be able to locate the components 
listed in the diagram above. You first need to lift clear RP15, 
DP24, DP25 and DP27; RP15 is a resistor, the rest are diodes. You 
can either cut the components clear or as I did desoldered them 
from the foil side of the board. Lifting these components clear 
automatically isolates the required pins of the 8252 I.C.

     Next, solder together the lifted ends of the components and 
connect the positive side of an IN4001 diode; the other side of 
the diode is taken to +5 volt supply at J130. The IN4001 was not 
part of the original circuit but I decided to add it to help 
protect the 5v line as this connects to most of the decoders 
I.C.'s.

     The next part of the original mod involved connecting a 15 
volt zener diode from J108 to earth. Most people complained that 
this diode got "mad hot", and I have to agree with them it does. 
Therefore, I decided to limit the current flowing into the zener 
by replacing link J108 with a 1 watt 47R resistor. This does have 
the effect of cooling the diode, but in anycase you will need a 
fairly large zener, I used a metal can 10 watt type and that just 
run warm. I could not obtain a 15 volt diode so I fitted a 16 
volt zener to my unit. The negative end of the zener connects to 
ground and a convenient point is link J120. 

     Thats it, all you need to do now is put together your decoder 
and check if it still works. I understand that there are a number 
of other mods available including a full cardless modification, 
if you have details please pass them on. I would also like to see 
the same mod to the internal decoders fitted to most receivers 
now.

73's John G8VHF @ GB7CRG   



----- End of message 35535 from G8VHF @ GB7CRG.#11.GBR.EU -----

