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sparkey

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Joined: 15/06/2011
Location: Australia
Posts: 819

Posted: 11:07am 12 Jul 2011

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i have a studio series silicon chip pre amp ...it uses 5 v switching to select and change the input select ..ok so i am going to use the pre amp re modify the output from the switchable inputs by passing the preamp section using the line out and then
using the digital pins to select from 6 possible in puts ...am i making sense to any body so when i wire the origanal selector switch wires from the switch to my own design interface board i wont need a expander board as such just a matter of cutting tracks on the pre amp board and feeding the output to the rca socket of the monitor and then i can plug up to six camereas into it ...oh i dont use the preamp any more ..got a rotel for that so i do like a challenge now its just a matter of writing the program to run it ...

regards sparkey,,,,old junk can be handy ...///Edited by sparkey 2011-07-13

technicians do it with least resistance

stuarts

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Joined: 15/06/2011
Location: Australia
Posts: 199

Posted: 02:04pm 12 Jul 2011

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Sparkey, are you talking about an audio preamp here. If you are, I'd check that it passes video ok before cutting too many tracks.

Stuart

Time is nature's way of keeping everything from happening all at once.

sparkey

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 819

Posted: 07:40pm 12 Jul 2011

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its the mother board out of the studio series preamp i bought it as a stand alone pcb kit "k55022a1" any way it has five 5 volt relays if you read silicon chip you would prolly have the article ...any way all you need to do ..oh yes it passes video first thing i did really ...now remove the two caps behind con 13/14..there 47 uf bipolars this breaks the audio output from the switching cct`y next replace the five bc327`s with bc640 fit as per overlay ..next remove the 3.3k and ten k resistors on each relay next pull up one side of the five resistor links 0"ohms" remove if you want and then from the 5 volt line fit diagonally to the collectors do this on all five so that you now have 5 volts running into the collectors....next i fitted 270 ohms to the base`s of the bc 640`s prolly could fit 1n914 diodes if you wanted but i thought that 270 ohm would be ok ...prolly go higher in resistance if u wanted too...having done this so far i connected up a flat 9v battery to the 5 volt line battry voltage was about 4.5 volts its what i had handy...then i also had a couple of 1.5 volt batterys in a holder so they read 2,8 volts hooked the negatives together and then one by one i applied the 3volts to the 270 ohm resistors reylys clicked a little hard but working so next i made a cable from the
original switch cable and have it ready to hook up to my made up veroboard mini breakout board ...thats basically it the preamp ccty is isolated from the switching cct..and cut the two tracks from the five volt rails that run accross the board just past the last relay ...thats about it for tonight tomorrow i will sit down and write a programme to run the thing any tips on switching on the i/o pins for say 20 seconds at a time would be appreaciated as i am fairly new to actully writing programs ...all i need to do as well is run 5 volts from the maxi to the five volt rail and have the i/o pins switch up to 3volts max really ...hope you can make heads and tails out of this ..its around five thirty in the morn i`m tierd gunna catch some zzzz`s...thanks for the reply...

technicians do it with least resistance

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