Need help from the experts (Jerrold DP-7 repair)
Mixmaster
I am trying to repair a General Instruments DP-7113 (Jerrold Impulse)
converter and need some help. Well, actually a lot of help. :)
Problem:
Someone tried to make it get scrambled channels by shorting pin 24 of u5
to ground which supposedly would clear a RAM chip. (u5 = LC3518BL-15)
(I did measure a few volts on this pin, when it was unplugged, so it
could be some type of battery backed memory device.)
Symptoms:
* No usable signal comes out of the converter (to TV) when it
has a good cable signal going in to the converter.
* Channel + goes down from ch. 02 to ch.01 then stops there.
(it should go up from ch.02 to ch.61 and then recycle.)
* Channel - seems to work ok but only goes from ch.32 down.
* F0 reports EA (wrong serial #)
* F1 reports -0 (disconnected & FM data ok.)
* F2 reports 0F, 1F, 2F... for a serial #
(I have the original serial # if that matters.)
Questions:
1) Any suggestions on what is broke, where to start, etc...?
2) What is u5 (LC3518BL-15)?
3) Where can I get schematics for this box?
4) Is there a way to reinitialize the unit to clear the F# errors?
(F0: wrong ser #, F1: disconnected, etc...)
I don't need any info about descrabling any channels. I just want
to get the converter working again. Thanks in advance.
Huge Cajones Remailer
------ (------@netcom.com) wrote:
: On 29 Jan 97 01:04:13 GMT, mixm...@remail.obscura.com (Mixmaster) wrote:
: >I am trying to repair a General Instruments DP-7113 (Jerrold Impulse)
: I'm by no means an expert, but it sounds like the converter has been
: "disabled" (shut down). This happens if:
: A: The cable Co shuts the box down via a data signal, usually due to
: non-payment
: B: The box has timed-out from being disconnected from the cable too long.
: These addressable converters need to be "addressed" via a data signal from
: the Cable Co continually, or they time-out at some point (time varies) and
: the box essentially dies. ;(
So, I need to send the proper activation signal to the cable box?
(e.g. box with ser.# xxx please turn on/wake up).
1) Where can I get test equipment to do this? Will a 'cube' do it?
2) Can I make the converter non-addressable so this doesn't happen again?
3) Where can I get technical data about the converters (schematics,
addressing specifications, etc.)?
: Hope this helps.....
Yes it does. Thanks for the help.