wtm@neoucom.UUCP (Bill Mayhew) (02/05/90)
Hi I've been charged with the duty of repairing a sickVideocipher module. It is a 0192-xxxx serial number with the full-size board and green plastic covering the DES parts. Apparently something went wrong with the power (clumsy installation with the IRD plugged into the wall?) and cooked part U1. There is a little filter choke (L1) to one of the power pins on U1, and the paint on L1 shows definite signs of over-heating. U1 is a CN 4071 (8 pin, apparently a buffer of some type). The symptoms are that the videocipher apparently still works most of the way. FA channels, such as the Weather Channel or PBS A-sched are still received and decoded correctly. SM channels such as pay-per-views and non-authorized stuff is still masked out. SA cannels that are duly authorized such as prime time 24 bring up a picture, but no sound. The diganostic screen shows that the channel is indeed SA, but the error counter at the bottom hovers near the maximum value. For obvious reasons, I don't have schematics to the VC module. It looks to me like U1 must have something to do with switching between sending fixed key audio to the output DAC and picking off data from the DES output. Anybody know? I'd prefer to fix this bug myself since it looks simple ??. I broke the seal (tsk-tsk) to wee what was wrong anyway. It is possible to unsolder U1 and replace U1 without blowing away the seed keys? Checking with a voltmeter, it looks like U1 has no power on it when the VC module is out of chassis. Please note, this is not an attempt to pirate any programming. This is legally authorized VC unit. Bill