• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Melaka poor audio on ssb

I finally gave up and took it to my tech,. Basically it was butchered to hell and back. Its working fine now.. Thanks for the help, guys..
 
"Choppy and Distorted" usually means you have a bad coupling issue between two stages.

The Melaka uses the 360014B board...so IF you have that Schematic Great! Else, you should get one as well as the component layout one too. Foil side of it too, can help...

As SP5IT was inferring - if your AM sounds ok, and seems to show no signs of "pinching" - then the path to the AM Regulator should be ok. But are you sure? Does PA and FM mode also sound ok? AM Regulator can run in two modes - Carrier control (Forms FM and AM power) or open Throttle SSB mode (SSB where ALC is the limit)

But, it uses several methods to turn off the Regulator for SSB mode. If one of them isn't working right, you can get pinched or distorted audio.

That doesn't mean it's there either - you can get pinched audio effects from a poor tuneup - might be a good idea to double check work and verify your tune up is right - else nothing is going to work.

Lets' take a look...

Those are your tuneup locations...Alignment - Caster/Camber -Toe-In Toe-Out - Tracking

And there's your Mic amp section and it's related components...

So, did you do your homework and see if the Bias (TX) voltage at R217 is even there?

Did you check to verify ALC is working? (Removing TR32 and the audio clears up - well you have more work to do)

FM mode - does FM work ok or do you get "distorted results" in that mode too?

IF your only mode that gives you distorted audio is in SSB - then make sure AM Regulator and all it's systems are not interfering with the Radios' Full-Throttle control.

View attachment 28275


How about that wonderful Wall-Of-Wattage - the TX Strip and related components - did someone screw up a slug or is the Bandpass Filter out of whack? How about the Predrivers? Issues?

View attachment 28274

So please - tell us that you've done all we've asked you to do - so we can help you...Lots of people have stopped in to help - doesn't seem like you're getting anywhere - so work with us here...
Yup.... I just had my tech who has the right equipment look at it.. Only so much I can do. I'm not a tech and I have bad eyes so reading a scematic hard..
 
Good deal. One way to tell if a tech knows his stuff, if the SSB transmit audio is clean after he's done with the radio.

Sideband is a lot more finicky about alignment adjustments. Any one of them can hammer the SSB audio quality.

73
 

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated