After years I wanted to run my old Apple II Europlus again - I started the machine but nothing to see at the monitor - the disk II in slot 6 started also not to boot.
So I cleaned the board and tested every IC with the "Fairy IC Test Card for Apple II" - result: every IC is o.k..
I connected the disk II to an Apple IIe ... and ... while doing this I realised that 2 pins were not correctly connected to the disk card ... I put them proper to the card and in slot 6 of the Apple II Europlus - and he started to boot the Basic System - sounds correct (same sound like on the Apple IIe)!!!
But still nothing to see on the monitor (which is perfectly all right - tested it with an Apple IIe - cable also).
What could be the problem???
Would be happy about every idea that could help!
Some pics of the board:
At the moment you´ve posted not enough info´s to make any proposals or guesses...
Try booting without Diskinterface plugged in....
do you get the prompt and display without the disksystem inserted ?
If you get prompt without disksystem - then the trouble is located eiter in the controller or the Disk II.
In such case it´s rather common mistake - that trying to boot with misalligned cable
between Disk II and Diskcontroller - will have damaged parts on the controller
or the analog board of the Disk drive.
Thanks for the answer.
No, without the disk II there is also nothing on the screen.
The disk II is perfectly all right - I connected it to one of my IIe and it booted the Basic Systems o.k.
Meanwhile I tried to connect the Apple IIEuroplus to a TV over the 4 pins on the board using a modulator - there I can see "APPLE II" and the prompt!
Then you might have twisted the trimming resistor
( the one close to the 2 pin connector )
and the brightness/Contrast is turned down low.
Try again a boot without disk system and without
Try adjusting that trimmer to test if you get display.
Do you only use TV-set for display ?
What kind of display is used ?
don´t proceed unless you get display at the Monitor / TV set.
I booted without disk and tried to adjust the trimmer but absolutly no reaction ...
I use an Apple Monitor II (the TV modulator was just a test to see if there is anything written on the screen).
Another thing I just noticed - the tagged RAM becomes very fast very hot if the board is powered on ...
Then it should be replaced by another RAM. In general use the RAM chips don´t get that hot.
Do you have a Disk with test programs for the mainboard availiable ?
Do you have a link where I can buy RAM?
Don´t you have a 16kB Language Card sitting aside ?
some also offer U256D a RAM chip manufactured in the former German Democratic Republic,
but they did not have the comparable quality....
No, a test disk for the mainboard I don't have - what is the name of the program? Maybe I can download it from Asimov.
But so far I will replace the RAM. But if this doesn't brings something on the screen - I will have to solve this problem first...
o.k. the problem seems to be difficult ... I found a 16kb language card and replaced the RAM that became very hot - but - the replaced one also became very fast, very hot ???
I found this:
Clock frequency (timing could be slightly off or you could have wrong crystal)
Video Sync Counter (S-4)
Video Generator (S-11)
as possible problem points - where is S-4 and S-11 on the mainboard?
I beg you pardon, but what do you refer from when
using terms S-4 and S-11 ? Which book or circuitplan ?
I found it here at "no video":
Thanks for the link.....
well i finally discovered that Mike Willegal refers to the "Red Book"
Reference of the Apple II and there to the Block Shematic at
S-4 refers to page 144 of the Redbook and there to the row of 74LS161´s at location D11 to D14.
S-11 refers to page 151 and there to a huge bunch of Chips spread all over the board.....
Among all that chips i´d focus rather to the 2 74LS194 chips at location B4 and B9
and the 74LS151 at location A9 or the 74LS74 at location B10 and maybe
the 74LS257 at location A8.
I´d have suspected rather more:
74LS174 at location B5
Databus Buffer at location H10
damaged filter capacitor at supply voltage rail
nearby the heating RAM chip
Note i´ve enlighted my favorite suspects by bold printing.
Thanks for the explanation!
Therefore I have tested every IC with the "Fairy IC Test Card for Apple II" (done the long loop test for aged IC's) - result: every IC is o.k., it can't be an IC.
With "damaged filter capacitor at supply voltage rail nearby the heating RAM chip" - do you mean the yellow, red or blue arrow on this picture?
But besides: I also own a Fairy IC-Tester.....
and i´d give advice not to trust the results of that tests 100%
it´s a good "precheck" for simple check.... but that tests sometimes produce mistakes....
in that pictures something red is displayed ???
what kind of stuff is that ?
Thanks a lot!
o.k., I will order the mentioned IC's at ebay.
Question towards IC's: I found f.e. some it is written on them "SN74LS161AN" - on my Apple board is written on the IC "DM74LS161N" - makes this a difference, or can I order them?
Question towards filter capacitor's: On the Apple board is written on the blue one's "104Z5E" and on the red one's "00IK Mexico" - can you tell me, maybe from the "red book", how the exact description is (on this webppage I can't find them https://www.conrad.de/de/keramik-kondensatoren-o0245110.html ).
P.S.: the red arrow is on the last pic I posted ... but you answered my question perfectly - thanks
P.S. (2): I found in this guide www.appleii-box.de/H198HomeRepairGuide.htm 6 mor IC's that could be responsible for the problem.
If the replacement RAM chip heats up very hot also, are you sure it's oriented correctly? If it's been put in wrong, it will be fried/shorted.
reply to question 1:
If there are 2 letters before the number it´s abreviation of the Manufacturer and is not relevant.
SN is typical for Texas Instruments and DM is typical for National Semiconductor.
reply to question 2:
the filter capacitors have a value of 100 nF.
This is spoken 100 nanoFarad.
It sometimes is also abreviated by 0,1 meaning 10th part of 1 microFarad.
For better understanding:
1000 pico Farad is 1 nano Farad
1000 nano Farad is 1 micro Farad
1000 micro Farad is 1 Milli Farad.
if it´s coded by numbers the first 2 numbers are value and the third number indicates the amount of zeros.
so 104 = 10 0000 = 100.000 ( pico Farad ) = 100 nano Farad.
at conrad the correct link to the filter capacitors is:
additional info to explenation from Peter Rittwage:
All IC´s have either a notch or marking that indicates the side where pin 1 is located at the IC.
And at the Apple II mainboard all IC´s ( except those at 90 degreee angle ) have same orientation and
the notch must be at the same direction like the notch of the neighbor IC´s heading towards the frontside
where the keyboard is present!
Thanks a lot for your answers and explanation!
Yes, I've put the RAM in the right direction on the board - so it seems the filter capacitors are a problem!?
Great that you posted the link to conrad!
But what for a kind is the red filter capacitor where you drawed one of your arrows (left side of the board)- there is written ".00IK Mexico" on it - value 0 makes no sense or does the "." mean something?
Of the blue ones there are two types on the board - "104Z5E" and "104M5E" - I understand you in the right way: this makes no difference?
0.001K ( K is abreviation for Kilo = 1000 )
=1000pF = 1 nF
( attention - picture is wrong but value displayed in title is correct ! )
second question: correct no difference
Thanks a lot!
I will try to repair the board when the ordered parts arrive ...
In regards to your issue of no video from the output jack, I notice your cable looks very much like an audio cable. I know you said the cable and display are fine on a //e
however, sometimes the center pin doesn't make contact with the jack. Since you get video from an RF modulator, I would suspect contact in the jack on the board.
I tried also another cable- the same result.
So, I had luck - while I was searching for IC's I got an Apple II+ board on ebay at a lower price than buying all the IC's.
Here it is: an Apple II+ from 1981 ( I only had to replace 1 RAM).
I will use the other board (also 1981) as a reserve.
I checked the the board with the diagnostic programs - everthing works perfectly all right!
Question: The only point are constant light vertical lines on the screen - what could that be? Which IC should be changed (if so)?
Here is a pic (the fuzziness at the top of the screen is just on the picture - wanted to show the descriped lines):
I tested all above mentioned IC's from the first board - every one works on the second board - so must be o.k. - the lines on the second board are still there.
What can I do against the descriped lines?
That lines are normal.... they apear if contrast or brightness is turned too far up....
As retro gear said, if you can get stable video out of the 4 pin header, then the issue lies between the R11 trim pot and the RCA video out connector.
From you photo of the board it looks like the RFI model. There are only 3 components from the trimpot to the video connector, 4 if you include the trimpot.
If you had a multimeter you could check continuity from the centre of the video out connector back to resistor R10 (27 Ohms), there is an inductor connected from R10 to the video connector centre. There is a capacitor across the centre of the video connector to ground. The capacitor could be short circuit, the resistor or inductor could be open circuit.
These could lead to no display on the monitor.
o.k. I adjusted brightness and contrast - the lines are nearly gone ... nearly - but if that's normal ... o.k. - never saw that at my Apple IIe's.
I have no multimeter, but I think I will buy one - thanks for the description!
I just recognized that the bulb under the power button is missing ...
What type of bulb do I have to buy?
A small 5V rated one, like this one.
But you have to check if it will fit.
I recently took my Apple ][+ out of the closet and turned it on.
I had the very same problem of the vertical bars on the display in addition to random resets, freezing and disk drive read errors.
The first thing I did was to "recap" the power supply; its' been a wise decision since some capacitors were starting to leak.
With my disappointment the random resets did not disappear, so I went on searching for the problem and I accidentally discovered there were false electrical contacts in the "A" and "B" rows of the motherboard; it turned out that all the chips had to be pulled out from the motherboard, pins cleaned and chips reseated.
It's a tedious work but it's worth doing since I solved all my problems.
I no longer have vertical bars on the screen and my Apple ][+ is now rock solid; it does'nt reset or freeze even fully loaded with cards (more on this in a following post) .
Luca, to pull all chips out of the board can help - as I said above - here not.
But this doesn't matter, because the board I bought works perfectly all right and now I have the other one as a spare part.