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Title: Communication on a 039 board Post by: Mirage_Chaser on December 19, 2013, 06:31:33 PM Can anyone tell me where com 3 is handled on the 039 boards? I have a game that I am trying to do tito with and I am not getting any signal. I think it may be the board but I don't have a spare to try it with.
Title: Re: Communication on a 039 board Post by: Foster on December 19, 2013, 10:20:32 PM You have to locate the communications board
it is usually located in the AC distribution chassis the board with the ribbon cable going to it from the motherboard. it is the 5 pin Molex SL 0.100 (all them are black) Title: Re: Communication on a 039 board Post by: Mirage_Chaser on December 19, 2013, 10:31:32 PM Thank you. I am familiar with the com board on the unswitched power supply. The com board is good. it is also not the ribbon cable and not the backplane board.
I am looking for the actual IC on the board that is responsible for the comm for channel 3. Title: Re: Communication on a 039 board Post by: TZtech on December 20, 2013, 04:57:41 AM Looks like level shifters at U76 and U80 with the actual comms coming from U31 (SC26C94) QUART
Did You check the unswitched PSU output voltage - Thats a fairly common failure point. Title: Re: Communication on a 039 board Post by: Mirage_Chaser on December 20, 2013, 09:45:10 AM You mean on the 5 volt side? I'll double check. Thanks for the info. I remember the quarts being senet but I wasn't sure if it did the more complicated messages.
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