Re: 2e Problems

[pbauer@ATHENA.MIT.EDU (Paul H Bauer)]

	Info on 2e problem

			
        >Regarding my sick AIIe  here is what I have done so far.
>     1: With nothing plugged into the board but the key board all I get
        is vertical bars on the monitor.


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        sorta like this pattern?

        if so, the CPU is not operating.  This is the default memory pattern
        for the text page 1 memory.  It is currently in the default lo-res
        mode.  The first thing the CPU does is lift up control-reset, which
        will reset text mode, (that's in the hardware BTW) and then start
        executing the reset code in ROM.  The CPU is NOT performing this
        reset-procedure.  The screen will look like this with the CPU unplugged.

        >     2: I replace all the ram chips and put the old rom (cd) + (ef),
        6502,and character generator from when it was a unehanced IIe ,
        I pulled all the socketed chips out and put them back in with no
         change
>     3: The power supply voltages are okay.
>     4: If I put a drive and a card in slot 6 or 7 it won't auto boot.
>
>AND NOW FOR THE KILLER:
>
>     5: My friend paul said why don't you plug in a AE Transwarp card
        in and see if if it buy passes the problem. And would you believe it he
        was right. Now I get the IIe on the monitor a drive will work
        and a  program will run. It also runs fine with the enhance
        chips put back in and the Transwarp still installed. that's
        because the  transwarp card is using its own CPU, bypassing
        the 6502.

>     I hope I've provided enough clues so some body can tell me how to
        fix my CPU.

        hehe, REPLACE it.

        >Thanks

>
>      Also another friend has a 2c which is doing the vertical bar
        problem >but he does not have the option of inserting a
        transwarp card. Any insites would really be appreciated.

        probably the same problem.  Oh, also try re-seating the CPU in its
        socket - mine has to be wiggled around a bit to work right, and it's
        best to do your wiggling with the power OFF.  Try it 5 or 6 times to be
        sure it's not the socket.  Borrow a 6502 from someone else and see if
        that does not fix the problem.

        One other possible cause is if the clock (TMG) circuits are not 
        working. No clock signals means the CPU does not move.  The
        likely  problem is either a TMG chip, bad transistor in the
        oscillator, or bad crystal (XTAL/XTL) in
        the same oscillator. (funny metal can, usuall strapped down on 
        its side, two wires out one end)

        "When in doubt, swap it out"


        > PS   The vertical bars are solid color alternating with black, not
        > charecters if this makes any diffference.

        they *should* be solid white and solid black bars.  (not characters,
        sorry I was not clear in my last mail)  If you've replaced the
        CPU with no luck, definitely check the clock signals.

        good luck!

        Paul Bauer


        From: Jim Royal <jimr@eicon.com>
        Subject: Vertical bars
        Date: Thu, 20 Oct 94 10:37:00 PDT

        Hi.  I'm posting this reply to comp.sys.apple2 in response to your
        question, but I'm also e-mailing it directly to you because my 
        access to the newsgroup is so slow.

        You said:

        > Also another friend has a 2c which is doing the vertical
        > bar problem but he does not have the option of inserting
        > a transwarp card. Any insites would really be appreciated.

        The vertical bar problem can be cause by a badly-seated 6502 chip.  I
        have a IIc with a Z-RAM Ultra card, and a Zip Chip.  The Z-RAM
        sits in the  sockets for the CPU and MMU. If either of these
        items is not making proper contact with the sockets on the 
        motherboard, then the vertical bar problem can
        occur. It scared the hell out of me the first time it happened. Seating
        the board firmly solved the problem.

        If your friend has neither of these products, and has, in fact, never
        opened his IIc, then open the machine and check the seating of 
        the CPU and the MMU.
        The MMU is directly "north" of the CPU.  Both are under the keyboard.

        Good luck.

        Jim Royal
        jimr@eicon.com


        From: j.stosez@genie.geis.com


        The 74SO2N next to the 65c02 was the culprit I'll do some
        testing  later.Thanks for the help and encouragement.

        JACK