Re: Apple II plus hardware problem

[NOSPAM@PRODIGY.NET (Andy)]

Hello Allen, it sounds like you may have more than one problem with
your Apple II+.  In addition to what Rubywand suggests, you might try
to check the keyboard encoder chip on the small pc card under the
keyboard.  If you can get a schematic of the keyboard, you can check
the chip with an ohm meter (diode checking mode-Apple turned off) and
compare the resistance from ground to each of the matrix keyboard
pins.  They should all be the same resistance value.  If one is
different, the keyboard chip is probally bad.  Your best bet is to
purchase a non-working Apple II+ on Ebay and scavage for parts as I
couldn't find the keyboard chip anywhere.

Good luck,

>>> Andy
+ + + + + + + + + +
On Sat, 28 Oct 2000 09:39:30 +0800, "Allen Bong" <sfbong@tm.net.my>
wrote:

>Hi All,
>
>My Apple2+ recently developed an intermittent problem.  When I switched it
>on, It went straight to low res graphic mode and the whole screen was
>scrolling up accompanying with the constant beep sound.
>
>I checked with a logic probe and found F14 74ls259 pin 4 to pin 7 were all
>L, so I suspected that F14 chip was bad.  I changed the chip and the fault
>disappeared for a while and as soon as I plugged in the keyboard the same
>fault came back again.  I'd removed all the cards plugged in the slots when
>I did all the test.
>
>Is there anything other chips that would caused this problem ?  I'd also
>soldered the 6 eproms directly onto the PCB as the sockets were giving other
>problems last time.  Please help me if you'd any clue for me.
>
>TIA.
>
>Allen
>
>