[TMRA] Digital stuff.

[Brian Knoblauch]

    OK, thanks to a day off work I had a couple hours to poke at it (usually 
I can only get a few minutes here and there, which is horrible for 
troubleshooting)!

    I verified all the cable pinouts/connections first (thanks Steve KC8TVW 
for some pinout info he sent me directly).  Then used the IC-7000 speaker 
output (in headphone mode) directly into the computer line-in to verify my 
line-in is still working.  I then pulled the SCI cover off (while still 
attached to the "Data" port) and grabbed a loose cable to connect to my 
line-in on the computer.  I used that cable to poke at the circuit in the 
SCI in various locations and was able to learn that the "Data" port is 
indeed putting audio out on the "AF Out" pin, and it's making it through the 
cable to the appropriate wire inside the SCI.  However, it's disappearing 
somewhere between there and the cable that should go to the computer's input 
(not showing up anywhere, I was hoping it would be on the wrong cable...). 
I flipped the system around, using the radio headphone out to drive the 
"computer" side as well, and same deal that way, I get audio into the box, 
but not out the other side.

    So, the good news is that the Icom data port af out pin really does 
output audio at line-level, and that line-level is accepted by the 
soundcard.  The bad news is that my signal is disappearing somewhere on the 
interface circuit board...  So, next step is to pull the PCB out of the 
enclosure and start the tedious process of debugging the circuit...  It's 
not terribly complex (basically just a gain control and a transformer for 
isolation), but still, everything is really close together and hard to work 
with!  (Yes, I could just modify my cables to have the audio bypass it and 
just use it for PTT activation, but that would be giving up)  :-)

Thanks,
Brian KD8COO

----- Original Message ----- 
When I first got it I do recall hooking up an external TNC via the DATA 
socket.  I recall it working and having no issues.

I'm looking at the IC-7000 manual now.  On page 12 the table for the DATA 
socket pinout looks like it has one pin for AF OUT (pin 5) and one for DATA 
OUT (pin 4), but the DATA OUT pin looks to be only if you've got it in 
"9600" mode.  I would assume that regardless you should get audio on at 
least one of these at any time.  The IC-7000 has a menu setting for putting 
it in "9600" mode... menu M-3, then button F-4 should toggle it (page 116 in 
the manual).  I think it'll say "9600" somewhere on the screen if it's in 
that mode, so I would assume that if you don't see 9600 on the screen, then 
you should get audio on the AF OUT pin on the DATA socket.

My only other thought here is that maybe the AF OUT output is "line level", 
and not strong enough for the soundcard to process?   This is just 
speculation.  But on page 12 of the manual in the "ACC Socket" table for pin 
12 "AF", it notes that the output level is "100-300 mV rms".

<second message>

Brian, also, since (still on page 12 of the IC-7000 manual) the 
"description" for Pin 12 in the ACC Socket has a note that the AF out level 
is "fixed", but there is no such note for the AF OUT on the DATA Socket, I 
would assume that the level is NOT fixed on that one.  So you might try 
cranking the volume knob all the way up to see if that can give it enough 
power to register with the soundcard...