Hi
I got an Apple II europlus motherboard...
one rom is missing but I was thinking that if I was trying to switch it on
I would a least get a bad video (garbaged)
I have absolutely nothing... (no composite signal)
on an Apple II does it need a working 6502 to get a composite signal ?
on my IIe when I repair it (no ram working, I had a signal
I guess it's coming from the clock ?
thanks
Yes you are missing the timing generator clock signals. Even a bad 6502 will give you bars or something onscreen.
Likely a chip at location B1 B2 C1 or C2 for starters
Larry G
thanks for the information, not I'm sure of what I have to fix first
any idea if an apple II europlus can start with only 16k of ram
the idea is to install only 1 row of "working" 4116
to see if it starts (once the clock is fixed)
and then test the rest of the 4116 with this working row
in install the ram when I'm sure that the 4116 are working...
thanks
TOP RIGHT "SEARCH"-Field to find previous threads about that topic...
it would display threads with link to:
http://www.appleii-box.de/D04_resurection.htm
missing input in postings ( like no pictures or info which ROM is imissing )
leads to none reliable output....
speedyG
>any idea if an apple II europlus can start with only 16k of ram
From what I understand, the EuroPlus was basically an Apple II+ with PAL video and slightly modified Applesoft.
I would think it could handle 16K. When Applesoft is first inited via $E000 it does a scan for how much memory
snd plugs the # of pages in $74 normally $C0 for 48K but would be $40 for 16K. Yes, what rom is missing?
Larry G
how about reading the page i mentioned above - the answer is at that page...
great website, I think I have all I need to repair it now
my question crossed your answer... (when I asked your answer was not yet visible)
thanks for all your help, I guess I have all I need to repair it
Thanks
dead 74LS195 in C2
I know have a screen alternating between (totally white and black and white stripes)
and also 2 beeps, so the cpu starts
with some ram vertical stripes and with some other horizontal
Finally several other chips dead...
74LS86, 74LS174
then the nice eprom (looking brand new with a nice label) was with a wrong timing...
the content was ok, copied to a AT28C16 I got an image...
I have a few questions...
I'm waiting for a ps/2 to apple 2 keyboard adapter (waiting for osh park)
also waiting for Apple ROM to AT28C16 (also from osh park)
I guess the apple is stuck waiting on a missing keyboard...
any way to un lock it to see if I get a "Apple ][" message ?
for example with a pullup on strobe ?
I saw on a web site that apple could have either a 9334 or 74LS259
are these chips compatible ? exact replacement
or some apple boards used the 9334 and some others the 74LS259 ?
thanks
Hi,
The Apple II does not need a keyboard to show the boot screen ("Apple II" on top). The prompt with flashing cursor will only appears if no disk II controller is present).
Yes, the 74LS259 is equivalent and pin compatible with the 9334.
Some boards use the 9334 while others use the 74LS259.
Thanks to all,
this board is finally working...
I'm now waiting for the rom and keyboard adapters from osh park...
I have a new symptom...
the apple alone seems to be working fine...
but as soon as I try to plug a Legend 128K ram board the machine is not responding
Large and very fine bar pattern on the screen
bus crash even without any rom so the problem is not due to an INH problem
any idea ? is there any common errors due to language card looking like this one ?
thanks
Why INH ?
ever thinking about the Legend locking up a line in the Data- or Adressingbus ?
Turn back to Posting #3 and reread....
sincerely
SpeedyG
INH simply because rom replacement are sometimes not working with language cards
the legend 128 is seen as a language card with extra port...
as I have eeprom replacing standard Apple Rom, I also tried without any rom/eprom installed
the looks does not look like the case with data line stuck...
but you gave me an idea to try to find the solution...
I think it's due to a chip too slow to deselect
I'll try to find the schematics of this board...
btw I received my rom replacement from oshpark.com they work...
I also received my keyboard adapter PS2 -> Apple II
I'm working on the code...
thanks
a few extra bad chips on this machine again... (4116 bought on ebay)
lot of oxydes removed...
rom adaptor working now the apple soft starts
legend 128k working (also a lot of oxydes) + a few dead chips
partial keyboard (I have to finish the software for my adapter)
what sort of memory test do you suggest for the main memory and for the legend 128kde ?
thanks
hello dvador,
for Ramtest in the first row:
First, I suggest you try this simple 48K RAM test (thanks to Jim Sather and his precious book "Understanding the Apple II") :
1. Go to the monitor (CALL -151)
2. Type in the following code (don't forget the space between 34:14 and Return).
C050 C053 C054 C057 N 265:FF N 266<265.BFFEM 266<265.BFFEV 265:0 N 266<265.BFFEM 266<265.BFFEV 34:14 (Return)
The Apple II will go to HGR mode and display white and dark graphic screen along with question marks and inverse @ characters at the bottom of the screen.
If some RAM chips are bad, faulty addresses will be printed on the bottom of the screen.
Make sure there is a space between the 34:14 and the RETURN otherwise it will only run once.
If any numbers/letters/memory locations are printed out you have bad ram.
and reread:
http://www.applefritter.com/?q=content/null
related to the legend card:
if the original software isn't availiable - maybe a test for similar card works at least partially:
ftp://ftp.apple.asimov.net/pub/apple_II/images/hardware/storage/memory/
giving a try to that cards that have most smilarity -
like the Saturn card in DOS-Mode contains a ramtest....
The Legend-S-cardsoftware contains a utilitydisk with ramtest....
speedyG
Thanks for the information, I'll try it as soon as I have a working keyboard...
(should not be long, most of it is working, but still some missing keys)
btw: do you have any idea on how the reset works on an apple II europlus
actually it looks like a soft reset on Apple IIe...
(a looping basic program is interrupted and the control given back to apple soft)
any idea on how to do a hard reset on this machine ?
thanks
I have a strange failure on the apple II europlus
from time to time the image disappear or even seems to be flashing... (the entire screen)
I guess it's due to a loss of the video signal....
to get it back I have to turn slightly the TRIM around J14
apparently it has a name R11 (unreadable it's partly written under the trim)
the problem is that I dont get a stable screen after 10mn to a few hours
I have to adjust this trim again
any idea ? trim dead ? something else ?
it seems slightly worse since I converted the board to NTSC
I have a PAL encoder, but for a TV, not composite
I'll try to find a way to convert it to composite
the 2 boards looks very similar
then I may switch back to PAL
no idea for the flickering ?
to get lores and hires working I had to change 3 other chips...
but for this flickering I can't find any reason...
it's like if at some time the video signal was just missing... (so the adapter try to adapt to another signal)
when I have a page with a lot of graphics, the image seems stable
any side effect of the color killer ?
thanks
One of the most common reasons is:
Bad contact or oxydation at the rear Videoconnector or between the plug of the
videocable and the rear connector - or a damaged coppercore inside of the videocable....
SpeedyG
Hi SpeedyG
thanks for the help, I'll check the connector...
I already removed a lot of oxyde in this area
the cable is clean I use it with several other machines..
this machine is full of surprises
the CFFA3000 fully works...
after the graphics
and my keyboard adapter is almost fully working....
thanks
Hello dvador,
glad the info's help ahead.....
it's a challenging struggle to keep that stuff up and running...
SpeedyG
I fact the problem seems different...
when I have no boards connected, the screen looks ok...
(for example the memory test)
but as soon as I add a board the video problem starts to occurs...
till now I used 3 boads...
- CFFA3000
- Disk II controller
- Legend 128k
any idea ?
thanks
In fact no problem without any card in the slots...
I insert any card in the slot even not activated and the problem starts...
I check the power supply same values with or without card...
when I say "not activated": I inserted some board that need external software
such as the mem/dos board or the microsoft cp/m board
related to Slots:
IOSEL,DEVSEL,IOSTRB....
74LS138 at H2,
74LS138 at H12,
74LS138 at F13..
and partially
74LS08 at H1.
SpeedyG
Thanks for this information
I tested the 74LS138 recently but not the 74LS08 H1
I'll retest them..
I took the board with the less chips (the disk II controller)
and removed all the chips and reinserted them one by one
the problem occurs when the 74LS323 is in place, removed the video works
in any case the controller board is working when all the chips are on the board...
thanks
Thanks for this information
I tested the 74LS138 recently but not the 74LS08 H1
I'll retest them..
I took the board with the less chips (the disk II controller)
and removed all the chips and reinserted them one by one
the problem occurs when the 74LS323 is in place, removed the video works
in any case the controller board is working when all the chips are on the board...
thanks
74LS323 ???
Where is that chip located???
take also a look at the "Arbitrary Chart" at :
http://www.appleii-box.de/D04_resurection.htm
and compare chips.... or mail link to picture of that Mainboard here.
SpeedyG
this chip is ont the Disk II controller...
without this chip, the controller is not working but no video problem...
with this chip the controller works but the Apple is unusable due to the video problem...
Then the Timing on that chip disturbs the access to the
Databus try another one with better timing...
Sorry it's not this chip the problem is on the motherboard....
this Disk II controller works perfectly well on several machine
and any board inserted in a slot has the same effect...
it's not linked to the 74LS323 itself but one of the signals
connected to this chip
one of the signal has a problem and actullay I dont know which one...
I checked the 74LS08 and 74LS138 they are ok
I have to analyse the schematics of the motherboard
and of the disk II controller to try to understand which signal
is involved in this problem
thanks for your help
Timing might work in another mainboard... that's not really excluding the chip....
at the other hand....
the 2 Bufferchips ( at some boards 1 Bufferchip ) at the Databus have a limited
"Fanout" ..... in case one of the cards or a chip on the mainboard drag too much
power that might be the trouble to the Databus....
similar is valid about the 74LS257's at B6 and B7
and the 2x 74LS174's at B5 and B8.
SpeedyG
I also changed these chips (with brand new one)
there one strange effect:
when in text mode the flickring makes the machine unusable (I rarely see the text on the screen)
when in graphic mode (loderunner) the screen is mostly visible just a bad effect of fast redraw...
it look almost as if the flash timer was interrupting the screen...
but why only if a board (any board) is inserted in a slot...
in fact apparently the problem occurs when there is any load on the databus...
but the machine always starts and never crashes...
strange thing to remember:
chips are not made for eternity....
no but they have a long life if they are correctly stored...
some of my old boards are like new
the most remarkable is a 64k extension for commodore 8000
it look like if it had just left the factory...
I'm thinking that the problem on my europlus is not due to a problem of logic
but rather some interference with the video signal...
I'll try to build a kind of shield with aluminium paper to put around the disk II controller card
to see if the problem appears / disappears when I remove / place the shield
it will probably takes several days, I have to find a way to make a shield correctly isolated
to avoid short circuit...
I'l also try to follow the video signal with the oscilloscope from the output of the last logic circuit to the video connector...
I'm convinced the problem is in this last part...
I think the video signal is mostly correct but from time to time another signal is superimposed on the video signal
when it happens I guess the composite to hdmi is loosing the signal and is trying to recover it
these adapters are often cycling among several configuration when they are not locked on the signal
I finally found the source of the problem...
it's effectively a problem of interferences...
between the Apple II and the composite to HDMI adapter...
connected to my TV it works
it's strange this adapter worked fine with many machines...
Apple IIe
Tandy coco 2 / coco 3 / MC10
Commodore 64 / sx64 / vic 20 PAL / vic 20 NTSC / C116 / plus 4 / Commodore 8032
Thomson MO5
Atari 800xl
Oric
in short I thought I had the right adapter...
and never thought the problem could come from there...
now I have to check the difference in the video signal of these machine
I dont understand why this apple is not working like other machines...
I will compare the generation of the video signal (from the clock to the output)
the machine never crash so I guess the problem is not related to the bus...
I check the signal from the Apple and the signal from a VIC20 NTSC
on the vic 20 we clearly see back porch / synchro / front porch / color burst / data...
on the apple:
the back porch is not clear and seem spartly merged with the syncrho
the colors burst seems to start in the synchro
I'm think that my samsung tv (where I get a stable image) is counting the lines as Rainman was counting the cards...
do you know if it exist somewhere a web site with the images of all signals composing the video signal (before they are merged)
I would like to compare each component to see if one is not correct
I'm thinking to a problem on vsync...
thanks
Finally I found a solution with this screen: T24E390EW
not so expensive (around 150 Euros)
has 2 HDMI/VGA/Composite/Component/Peritel
works with my old machines (including the Apple II)
also works as a standard screen for my PC
and has a TUNER....
With the Apple II europlus the image is good in graphic mode
and not some good in text mode, (some waves of color (very dark blue) perturbating the image from time to time)
at leat not loosing the vertical synchro...
I'll find a solution later...
Sorry it's me again with the same problem...
with the new screen and the stable image its easier to see the problems..
I made the following experiences...
1/ I cut one leg of resistor r6 I loose the color but the black and white image in mode text looks perfect...
2/ I reinstalled R6 and removed R27 then I reconnecte a resistor of the same value to the base of Q6
and connected altenatively to GND and +5v connected to GND I have the problem, to +5V a perfect image
3/ I checked the signal (normally connected to R27) and found 4v