• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

2225 with poor FM reception

You should try tweaking the trimmers for the FM RF. Tune in a station near the top of the dial, and rock the trimmers above the sections of the tuning capacitor that have the few widely spaced plates, while watching the peak tune meter. Don't mess with the local oscillator trimmer (the one all the way to the left) unless the dial is way off the frequency of the station near the top of the dial. If the dial frequency is way off, check that the pointer reaches both ends of the dial before touching the local oscillator trimmer, and be aware that the different type of trimmer used for the local oscillator is subject to breaking when adjusted, so don't move it unless it is necessary.
 
AE Bob said:
You should try tweaking the trimmers for the FM RF. Tune in a station near the top of the dial, and rock the trimmers above the sections of the tuning capacitor that have the few widely spaced plates, while watching the peak tune meter. Don't mess with the local oscillator trimmer (the one all the way to the left) unless the dial is way off the frequency of the station near the top of the dial. If the dial frequency is way off, check that the pointer reaches both ends of the dial before touching the local oscillator trimmer, and be aware that the different type of trimmer used for the local oscillator is subject to breaking when adjusted, so don't move it unless it is necessary.
Click to expand...
Thank you, @AE Bob . I will try. However I am suspicious of H305 because sometimes the right channel goes out and when I freeze sprayed it the right channel came back. I'll let it sit and see if I can repro the issue.


upload_2021-8-5_8-2-8.png
 
Nothing on the MPX decoder board would have any effect the signal level on the meter etc.
 
AE Bob said:
Nothing on the MPX decoder board would have any effect the signal level on the meter etc.
Click to expand...
Oh thank you for that. If I am having an issue with the levels, is there a place other than the variable capacitor and trimmers that I should investigate? I am going to try twiddling carefully with the trimmer on top of the FM VC. Much appreciated.
 
ocdecio said:
Oh thank you for that. If I am having an issue with the levels, is there a place other than the variable capacitor and trimmers that I should investigate? I am going to try twiddling carefully with the trimmer on top of the FM VC. Much appreciated.
Click to expand...
Lets just handle one symptom at a time. Start with the reception because if adjusting the trim caps doesn't fix it, this will have to go to a tech with rf experience. Specialized test equipment will be needed to go thru each stage and find out where the gain is being lost.
 
dr*audio said:
Lets just handle one symptom at a time. Start with the reception because if adjusting the trim caps doesn't fix it, this will have to go to a tech with rf experience. Specialized test equipment will be needed to go thru each stage and find out where the gain is being lost.
Click to expand...
That is looking more like it. Thank you for all your help and guidance!
 
dr*audio said:
Lets just handle one symptom at a time. Start with the reception because if adjusting the trim caps doesn't fix it, this will have to go to a tech with rf experience. Specialized test equipment will be needed to go thru each stage and find out where the gain is being lost.
Click to expand...
If I move the trimp cap it is going to another station, but I am able to get back. Am I working the wrong one?
 
You are turning the wrong trimmer. The one you are turning is the local oscillator. Set that one so a station near the top of the dial comes in at the correct place on the dial. After that, tweak the other trimmers that are above the tuning capacitor sections with few widely spaced plates (the RF sections), to get maximum indication on the signal level meter. Do not touch the trimmer capacitors above the tuning capacitor sections with many closely spaced plates. They are for the AM tuner
 
So this one:

upload_2021-8-5_13-3-26.png

This is the closest to the few plates (the one on the right is the local oscillator) The black wire above comes from the antenna stick on the back.
 
Never mind - it is # 1, 3 and 5, I see the spacing difference now.
 
I turned one by one, back and forth, half turn one way, half turn the other way and both meters aren't moving. The "tuning" meter never goes anywhere when I change stations, and the strenght move very slightly when I tune a station.

When I turn the receiver, I get only left channel. If I spray freeze H305 the channel comes back. Something doesn't look right.
 
It is losing gain somewhere, due to a failed component. If you tell us where you live maybe someone will know a qualified tech.
 
I am in Orlando FL, hope you know someone that can help me - thank you!
 
You must log in or register to reply here.
Back
Top Bottom