Robyn SB-520

[Holydvr]

When I received this radio, it would turn on and it had no receive. It would click over to tx but had no power out. I replaced the driver and final as well as the AM regulator. The way someone had put it back together had most of them shorted with no screw insulator. Tx now seems to work fine on AM and SSB with good power out.

I plan on recapping the entire radio if I can get one final issue sorted.. SSB has great receive sensitivity as well as volume when the volume control is turned up. AM sensitivity and volume are horrible. The volume control has to be turned all the way up to even have a chance at hearing anything even a local is saying. Have to be fairly close to the speaker to hear it also. Anyone run into this before? I will continue to troubleshoot as I can, but figured I would see if by chance someone has seen this in this 858 chassis before.

 

[PSYKO_Inc]

My guess would be a bad cap somewhere in the audio chain. Since you're already planning on recapping anyway, it wouldn't hurt to move forward with that and see if it fixes the problem.

 

[nomadradio]

My first question would be what does the S-meter do? Does it fall off for AM and read normally for SSB?

Or does it show mostly the same on AM or sideband?

If it does, a bad electrolytic cap in the audio is where I would look first. Following the AM receive audio with a 'scope down the audio path would reveal the culprit. And if you don't have a 'scope handy, just changing all those aluminum electrolytics would probably fix an audio fault.

Probably.

Just make sure they ALL get turned around the right way.

73

 

[Holydvr]

I will have to check the s meter behavior from AM to SSB. I did not even think about that.