D-104 Squeals??

[Stoneman]

What happened to the D 104, I have a bunch laying around here, & figured I hook some up...I hooked two up today for a Navaho, both squealing like a pig...Changed batteries, still the same...Any clues to fix these, I used to beable to crank these up all the way...Cheerz!

[halfwatt959]

What model Navajo do you have? I have a 433, a 458 and a couple of old 30a s. The 433 has no mic gain that Ive ever found and all my d104s work great on it. The 458 has an internal mic gain adjustment . I pulled the vr out and wired a 5k pot on the outside under the bottom. All my realistic power mics work great with the gain at full throttle on both the mics and the radio. My silver eagle d104 I have to keep at about 1/4 power and the t-ug8s I can run about half way before the dreaded squeal. But the 458 just has unreal audio anyhow. Now on some of my radios Ive found that adding a .1uF ceramic cap from the audio pin to the sheild pin helps eliminate the squeal. As a last resort on one 458 navajo I did have to take the mic jack completely out, lenthen the wires and move it away from the front mounted speaker. I put it out the side and problem solved. Hope your problem isnt that drastic. Have you ever used them on the radio before? And or has any work or mods been done to it since then? I do know that I have never been able to get talk back or echo to work in any navajo. Sure it will work but there is that horendous squeal. If by some chance anyone knows how to pull that off I would love to know myself. Maybe this will help you IDK but good luck.
73s

[Stoneman]

I have the 431 AND THE 455...Both had no work done to either since the last time I had these hooked up..The D104's had been sitting for at lest 10 years..Neither radio has a mic gain, but all I can do is crack the mic gain on the mic's like a 1/4 way open..I was gonna try better ground, or new mic plugs, I just hate soldering that 5 pins....

[halfwatt959]

May try spraying all the contacts with a good contact cleaner and shine them up with fine grit sandpaper. After sitting so long I would expect to see some corossion or tarnish on the contacts. May even be a wire in the cord on one or two. Not likely but possible. Any chance you can try them on a different radio? And does any mic work on the radios? Seems like the problem may be in the radio if none of them work but who knows. Could even be bad solder joints on the mic jack itself. Thanks for keeping the old Navajos alive. I love them myself.

[Stoneman]

That's probably there biggest flaw, putting the mic jack right next to the speaker...