Low cassette input into /4A

[+acadiel]

I am having issues with my current main console (which I never used a cassette with) where the input into the /4A from the cassette recorder is very low (the white ear jack).  I'm using the standard cassette cable (mic, ear, and remote), and the deck works fine with other consoles.

 

The Output from the /4A is fine.  I can play the tape back (after yanking the ear cable) and it plays fine on the recorder.  Just that it is barely audible going into the /4A.  I've reflowed and checked all the pins on the DB9 connector.  I'm assuming this is a transitor, cap or other component that might be having an issue.  Anyone have any ideas?

 

[+OLD CS1]

My guess is something in the audio path to the jack in the recorder itself if all else is checking out.  Is this your only recorder?

 

Greg posted the schematics a while back but I do not have them handy.

[+acadiel]

14 minutes ago, OLD CS1 said:

My guess is something in the audio path to the jack in the recorder itself if all else is checking out.  Is this your only recorder?

 

Greg posted the schematics a while back but I do not have them handy.

I've tried multiple recorders and multiple cassette cables - so have eliminated everything but the console.

[F.G. Kaal]

Be careful not to make the same mistake I did many many years ago. When my new TI-Basic program failed to load I got the bright idea to use my brothers stereo system. Turned the amplifiers volume to a high level  and everything went fine ... until I saw smoke coming from my TI99 console. I quickly disconnected the cable from the amplifier. After some investigation I found that only one of the opto-coupler was a bit thicker than it used to be and had a little crack in it. But it stil functioned properly after this but my little basic program was lost anyway. I must have used a bad tape.

 

Fred

[Ed in SoDak]

It's sure possible some part was damaged in the past by a static spark or improper connection. Here's the schematic showing the cassette section.

-Ed

 

TI99_3.TIF

[jrhodes]

Try a in line audio amplifier between the tape player and TI?

[+acadiel]

4 hours ago, jrhodes said:

Try a in line audio amplifier between the tape player and TI?

That’s what I finally wound up doing.  It’s a replicated Radio Shack 277-1008.  It actually worked.