Mirage 88 squealing in truck

[Randy Nix]

I have a Mirage 88 which works fine on the bench, no squealing at all. As soon as I put it in a truck and key the mike I get a terrible squealing. It's been in two trucks with the same problems. Has anyone seen this problem before?

 

[King Mudduck]

Have you tryied grounding the chassis of the radio?in the past i have had the same problem and once i used a small wire attached it to one of the small screws that holds the radio cases on and the the other end to the seat frame it went away.maybe you could go with a var,talkback.

 

[nomadradio]

Hmmmm. Does it squeal with the talkback turned off?

Or with a different mike? If the plastic sleeve gets left out of the mike plug, and the 'shield' wire touches the inside of the metal plug barrell, this can create a 'ground loop' squeal. Trying the stock mike would narrow this down.

73

 

[ButtFuzz]

Take off those pants.

...or is TR32 removed?
...or is there a ridiculously high SWR?
...is the antenna properly mounted and grounded.
...are you running a kilowatt 'leenyer'?
...are you running a D-104 with the mic gain wide open AND TR32 removed?

 

[Randy Nix]

TR32 missing

TR32 is missing. I will replace and report back as to whether or not it fixed the problem. Thanks for the info.

 

[freecell]

that'll help........also check TR53, D70, D83, D92 and R249.

 

[RF- MATRIX]

check the mounting bracket screws they could be to long, touching the circuit board. Also check the so239 connector on the back of radio make sure its tight. Chech the very simple things first. It runs on the bench but not in the trucks! Something is being over looked.

Hope this helps

Tim Rfmatrix

 

[Randy Nix]

TR32 missing

I replaced TR32 and that fixed the squealing problem. We put it back in the truck this morning and it sounds great! Thanks for your help.