[Elecraft] K2 Troubleshooting question

[DW Holtman]

Hello,

Last night I was working on an older K2 S/N 02XX. I was going to install a 
SSB module and a RS232 adapter that I bought from a forum member. I 
installed the SSB with no problems. When I installed the RS232 adapter and 
turned it on, I got an error message (080) I think), I quickly turned it off 
and removed the RS232 interface.

Now there is no receive audio except when I select the menu. Also the S 
Meter bar graph completely quit working. If I have the menu selected, it 
receives. As soon as I hit menu again and the frequency is displayed, no 
receive audio. I hooked a scope to R17 on the control board, the mute line. 
It goes high when menu is selected and I can hear the receive audio.

Anybody ever seen something like this?

Thank you in advance.

Best,
DW Holtman
WB7SSN