has anyone come across this fault ? my spare Apple II + displays question marks and flashing blocks at boot and does nothing else.
no beep - nothing.
The PSU is recapped and functions fine on another Apple II
thank you all.
my first doubt would be about one of the RAMchips in the 16K in row C. I´d examine seating ( bent leg under the chip and not in the socket ? do the same examination at row H - CPU and Bustrancieverchips ) and if the seating is O.K. probably one of the 8 chips damaged. Try a row from another board where the chips solved a RAMtest successfully. If the board starts then examine the single chips - chip by chip - till you find the bad one....
final note.... that "bad" chip must not really be dead... maybe it works at another board with slight timingshift and does just have trouble in this board with it´s own timing....
i allways recommend to have one tested and trustable row of RAMchips on the shelve as spare and storage them in a antistatic foam.....
and just besides: it´s always a good idea to keep rows of chips together if possible to have entire rows from one manufacturer and one run at least one selection (refering to the timing mark of -2 = 200 nanoseconds as example ) .... mixing chips often causes trouble.... in this case one half of the chips ( D0 to D3 or with location marking C3 to C6 )is from another run than the other half ( D4 to D7 or with location marking C7 to C10 )....
just by the way ... the dust is not a good fried of that mainboard.... cleaning it might be a good idea too...
Looks like a reset circuit fault to me. Anything happen when you hit Ctrl-Reset?
Thanks for the info , I'll try more ram
Finding good ram is proving hard
Looks exactly the same as my problem.
If you search back, you will see me struggling with this. I also noticed the memory chips 'got warm'.
In the end, exactly as Speedy said, I took out all the RAM, found a cheap Atari 16k cartridge and used its chips in the first row. Once done, the machine booted and passed some soak tests. I spent days with all of the chips I extracted trying to figure out which were bad, but it was frustrating without better test gear and in the end they sit my my foam board with marker pen around them saying 'sort em one day'. Shame as it is alot of original Apple chips.
I have a full set of good ram to try , not done it yet but i will - im just doing a soak test on another Apple2+
man these Apples can be a pain sometimes....