Problem With DX-160 on Band C

[bludytiger]

I recently got a used Realistic DX-160 and love it so far, however there is a problem I am having on Band C. I am not sure if the problem existed when I first got the radio since I have been doing most of my listening on Band D.

The other night I noticed when tuning through Band C that I was getting no signal at all, and the AF Gain had to be turned up considerably to hear static. I thought maybe it had something to do with my antenna or just a bad night for listening so I would wait until another time to try again before worrying. In the morning I got up and decided to check Band C in the morning. When I started up the radio, it was working fine on Band C. I tuned into a station low on the meter an sat back and listened for a bit. However after about 2 minutes of listening, suddenly the signal was gone in a flash. The gain had to be turned up again to hear static and without adjusting the tuner, and the AF gain at full, there was no signal at all.

I turned the radio off and waited another day to see if it would work again on its own but after 24 hours, it is still not working. All other bands work excellent with no signs of problems. I stopped using the radio since in case so not to damage the unit.

Taking the upper and lower covers off and doing a visual inspection, I see no problems. I do have the service manual on PDF, but don't know where I should start. Any help would be greatly appreciated.

 

[Beetle]

First thing comes to mind is dirty contacts on the bandswitch. Get some spray cleaner and carefully clean all the contacts, paying particular attention to Band C.

 

[loosecannon]

you say that you do most of your listening on band D, but recently have been listening to band C, and this problem arose during this period.

i am curious to know if when the receive went out on band C, would it work if you switched bands immediately.

knowing this would help narrow down the cause.

if you're not sure, try the radio now on band C, if it is not working, switch to another band and see if you can hear anything.
LC

 

[bludytiger]

Thank you guys for the replies.

I don't think it is a problem with dirty contacts. I will try cleaning them later, but I did do a quick check before for connectivity between them with my multimeter, but should do a more thorough check I guess.

If I am on Band C and switch to any other band, it will immediately start working, and when switching to Band C again it will immediately stop.

On my way home today, I got an idea since the volume drops dramatically when changing to Band C, it seemed to me that it sounded as if it were getting no gain or signal from the antenna. What I did was disconnect the antenna and check the bands like that. Like I thought, the volume of the static was near the same on all bands.

This makes me think that the problem lies somewhere with Band C's connectivity with the antenna.

 

[Captain Kilowatt]

Check for bad connections around T3 and T8. Those are the bandpass filters in the front end. It appears that everything after that stage is common so the problem must be in the front end bandpass filter area.Also check around T13.

 

[bludytiger]

Thanks again for replying. I checked T3, T8, and T13, they all seemed okay with the unit off so I decided to try to turn on the unit and see if Band C was working right now, and it is.

I then decided to carefully prod gently on T3, T8, and T13. If I tap T13 on one side, Band C goes out, but if I tap it on the other side, it comes back. Obviously the problem is with T13, or its connection to the board. I am thinking and hoping that it's just a connection to the board, and a quick fix of soldering. I'm thinking that is the problem since I can touch the opposing side of the board where T3 connects and it goes out like that as well.

I'll try re-soldering it and let you know the results.

 

[bludytiger]

I believe that has fixed the problem. After re-soldering the joints, I cannot recreate the problem when tapping the sides of T13 anymore and signals seem to be coming in on Band C great now.

Thank you everyone for your help. I'll let you know if it starts to act up, but I think that has fixed it.