Hi,
I currently have two Apple-1 computers, one I made myself and another one I'm testing our for someone that bought an assembled board from Armin Hierstetter (https://www.apple-1-replica.com). Both computers work but I have trouble with the ACI (one I made myself and other one I purchased on ebay (https://www.benl.ebay.be/itm/266615745568?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=ODs0xQVESVG&sssrc=2047675&ssuid=zDO_mlSPQKu&widget_ver=artemis&media=COPY).
I mostly tested with the purchased board, casette interface & casette tape from the ebay purchase and an AIFF file from my iPhone.
I tried to load Basic by typing C100R and then E000.EFFFR + enter.
When I start the audio (from casette player or phone) while reading in, after a few seconds the characters on the screen start shifting towards the right, then onto the next line and after a while even changing to random characters. I tried playing with the volume but nothing seem to work well. In some ocasions I got a '\' when it was done, sometimes didn't happen.
When I type C500R, the screen starts doing the same thing.
The audio cable I use is a MONO kabel, could it be that I need a STEREO to MONO cable modification? (something I read in another question)
I'm almost out of things to try so if someone could help me with finding the issue, help is really appreciated!
Hi Xevro18 -
this is a very interesting case of misbehaviour during ACI loads, and I would like to give you an expert opinion about the possible causation(s).
Alas, Applefritter does seem to have problems with the video format you provided.
I've sent you a PM so you can send me the video directly.
- Uncle Bernie
You have to use Firefox and then right-click --> Save Video As...
Here it is inside a ZIP archive:
att.mDUX0BF55ee7X67_oNR11JOCC8fH8qD7gYyHzQW1fYg.zip
Strange indeed. Does the test program of the apple-1 manual work fine? Does a memory test also work fine? It only occurs when loading / instructing the ACI? Could it be that the terminal section gets cross talk on the bus with a failing 74154?
I am able to type in "0:A9 0 AA 20..." and when running, it prints out all ASCI characters in a continuous stream.
I can try to swap some ICs like the 74154 and see if it gets resolved.
I swapped the 74154 and it didn't help.
Now I noticed that my issue is perhaps not directly related to the ACI. When I type an instruction like the '0:A9...', after hitting enter it also shifted the whole line and output around 4 spaces to the right, but it doesn't do this consistently. When using the ACI it happens after a few seconds when the actual data starts playing.
Hmm don't think it is that related with the ACI but with the terminal section, look at the diagram here: https://sbprojects.net/projects/apple1/terminal.php
Maybe something is wrong in the input selector part as in the diagram, maybe swapping some ICs that affect that area is worth trying out?
what kind of keyboard are you using? You cross tested that?
I use a Datanetics Rev B Keyboard (have 2 of them https://www.benl.ebay.be/itm/266912262950).
On my own Apple 1, I sometimes have some trouble when typing. It types an extra character, sometimes multiple or I suddenly can't type anymore. Typing on the other Apple I works fine ( I think sometimes is wrong on my own Apple 1).
In one of the keyboard cables I found a wire in the connector that was connecting to a pin next to it.
After trying everything I got no result, finally I soldered the 6 damping resistors in and this solved my problems.
The diagnostic program of Bernie that was in the PROMs and loading BASIC from a cassette tape both worked fine.
Thank you all for trying to help me out!