Post by Chris Tobar
Yeah, the SSC is in slot 1. I just double checked the switches and I did
have them set the way you explained, and the jumper is on Terminal. The
green select light is on the printer, and the red "error" light is not
lit. When I type PR#1, I don't see any ouput on the screen after that,
but the printer doesn't respond either. It doesn't do anything, it just sits there.
What I'm also wondering about is the dip switches that are in the printer
itself. They're inside, near the left front. I tried looking up
information about them, but I haven't been able to find much. I saw
something mentioned about "baud" settings on a couple of the switches but
I don't understand what that's about. (I'm pretty clueless about how
these early computers worked). I wonder if those switches are set wrong,
could that cause the computer to fail to communicate with the printer?
One thing I forgot to mention is that there is a small cover missing on
the printer. It's on the back top side. I can see a blue connector. I had
read that you could have an optional memory add-on, and I assumed that
was what the connector is for. I didn't think the cover was a critical
part or any critical parts were missing, also since the printer self-test
works. It prints the settings of the printer dip switches at the top of
the test page. So I don't THINK the problem is the printer.
I also don't think (or at least hope!) that the SSC is dead. I get the
"Apple SSC" prompt when I type IN#1. I'm really hoping that I just have
something set wrong.
By the way, I'm definitely still interested in getting a color ribbon if
I can get the printer to work! I know we talked about that in the earlier
topic. I was just given a Visa gift card, and I used it to order the
serial card and a couple of black ribbons. If I ever get this dumb
printer to work, I definitely want to buy a few color ribbons from you!
From the symptoms you describe, it seems that most of the SSC is working
and most of the printer is working.
The remaining "suspects" are:
1) the cable
2) the printer's RS-232 receiver chip(s)
3) the SSC's RS-232 transmitter chip(s)
If you write a short BASIC program to PRINT something ("Hello World!", for
example) continuously, then RUN it after typing PR#1, you should be able to
detect the serial data stream on the TX line at the SSC's connector.
The detection of the pulse stream can be done in many ways: LED plus
resistor, logic probe, multimeter (fluctuating average voltage), or
If the pulse stream is present at the SSC connector, the SSC is probably
fine, otherwise the problem is in the SSC--likely the transceiver chip(s).
Then plug in the cable, disconnected from the printer, and check the TX
line (called RX at the printer end) for the pulse stream. If it's missing,
the cable is faulty.
If both previous tests work, but the printer doesn't, then the transceiver
chip(s) in the printer probably need replacing.
Cables are pretty easy to check with an ohmmeter. All the proper
connections should have good continuity and no shorts to other wires.
Transceiver chips are easily damaged by ESD or plugging and unplugging the
cable without taking the usual precautions (units at both ends off, units
at both ends at same ground voltage, etc.)
It should not be difficult to get your printer working, though serial
RS-232 connections have a well-deserved reputation for having lots of
choices that must be made "compatibly" at both ends.
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com