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Old 7th Jan 2018, 3:20 pm   #36
Sean Williams
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Join Date: Feb 2005
Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW
Posts: 3,517
Default Re: 8085 processor questions

Righto, Power supply now repaired - a 5v regulator had decided to act as a short circuit.

A list of "Big" ICs on each board.

CPU Board

D8251AC
D8259AC
D8253C-5
Program Eprom

Printer Drive Board/Decoder Board

D8243C
D8741AD
D8039HL
2 Eproms

D8259AC
D8251AC
D8243C
D8253C-5
D8039HL
1 Eprom

Keyboard

D8039HL
22-950-38
FX1 059
1 Eprom

There are also 2 memory boards - from the description of the German machine that is similar, these two cards are only used for message storage functions, so as far as I can tell these will have little bearing on the basic start up of the machine.

The display driver board has a large selection of 74 series logic chips, which I guess must take the data from the CPU and convert it to something that the monitor understands.

Roger, I will have a rearrangement in the workshop to get the machine and scope closer together, so that I can take some screenshots of what is happening.

Cheers
Sean
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