Philips AZ2760 Cassette/CD Boombox Radio Losing Reception

[con3636]

Hello, I have an aging Philips AZ2760 Cassette/CD Boombox Radio and it's losing FM radio reception. It used to pick up all stations really clearly but now it only gets a few with a nice strong signal, I have tried playing with the telescopic antenna and even connecting it to an outlet ground, with no improvement. Are there components internally that can be replaced so the signal comes in better? Thanks!

 

[davelectronic]

Hi con3636.
I would look for any bad capacitors, mainly electrolytic's on the board, if you can get inside the unit, baring in mind you need to reassemble it, some units are difficult to get in to, some easy, i say electrolytic capacitors as there life is shorter than other components, like semi conductors etc.

 

[con3636]

I got it open without too much trouble, other than a really deep screw requiring a long screwdriver. All the caps inside looked ok, none bulging or anything. I tried adding some wire to the antenna to make it bigger but it still doesn't get reception on certain stations in it's spot in the kitchen. I wonder if interference or something has just changed for those stations and any radio would receive them poorly. Any solutions for making the antenna better or something? Thanks a lot for your reply

 

[davelectronic]

very much dependent on the frequency of the stations, but i would buy an antenna, or build a dipole, the internet can give lengths of cable for dipoles for different frequencies. you might be able to get a signal amplifier for radio / tv use, most cover a wide band range. google radio dipole, or build a radio antenna. what you said about weeker signal is probably the cause.

 

[con3636]

I was looking at the concept of dipole antenna, but they all assume a radio with an antenna of 2 conductors. Mine only has a single wire running to the telescopic antenna. Would there be another component inside that is the second conductor of the antenna?

 

[davelectronic]

One side of the dipole is the single reception wire, the active side, the other side is ground or the chassis which ever is ground for the unit.

There are calculators on line on other sites to help you determine cable length for any given frequency, generally the higher the frequency the shorter the antenna. ive converted a couple of separate stereo tuners to take a PL295 plug, it what i had lying around, But BNC or other RF connectors are just as good, i know use my nad tuner on an outside Aeriel.

 

[con3636]

I found written on the radio portion "Eco 5 Tuner Board" and I found it in this service manual on page 7B-1. Sorry, I'm kind of a noob, but I still don't understand where the second element of a dipole antenna would connect, the chassis is all plastic and it's cord has only 2 conductors. It looks like there is a tiny lead that has an "A" written next to it so I thought that might be it, but when I touched it with a wire I didn't hear any better reception on the radio. Is it the more wire the better for antennas or does more wire weaken the total signal? Thanks a lot for your help

 

[Resqueline]

On page 7B-4 (upper left) there is a 300 ohm connector 1101 connected to points T001 & T002, but it's probably an option instead of the 75 ohm connector.
Link 9128 goes to one of its connection (T001) and point A is the other.

An antenna can be as long as a full wavelength, next best a half, or third best a quarter. The wavelength [meters] is 300 / frequency [MHz].
But it does not sound like a bigger antenna will benefit you. I'm not sure what could be wrong with the radio section though. Could it have been dropped?

 

[con3636]

It wasn't dropped or anything, and it works perfectly on some stations, but others which it used to pick up (and can be picked up by our cars) barely come in. I'm not sure if maybe just the interference patterns have changed or what has happened. Thanks for the expertise on the diagram, I'll give it a shot with a super long, 2 element, antenna.