Charger needed for a Realistic dx 440

[st25r]

Wait, if FM isn't distorted through the speaker, then it's not likely a speaker issue.

If it's AM, there's a switch on the bottom right that shows Narrow/Wide. Try switching that to one or the other and see if it improves.

I played with and fiddled with those controls and the clarity of the transmission was still muffled although one could tell the filter was engaged because the sound changed. The only thing that improves the clarity is touching the metal speaker grille

 

[mmckenna]

I played with and fiddled with those controls and the clarity of the transmission was still muffled although one could tell the filter was engaged because the sound changed. The only thing that improves the clarity is touching the metal speaker grille

Did you try headphones?

 

[st25r]

Did you try headphones?

I knew I forgot to try something! I will do that tonight. One thing I noticed is the rf gain does not seem to work on broadcast AM. Reception is quite poor regardless of the dial position. 650KHz comes in on two different radios quite strongly, yet is quite weak on the dx440. The gain audibly works on SW and FM. When I touch the telescoping antenna I have a lot of interference on LW and broadcast AM. If the distortion goes away when I plug in the headphones what components should I check? Thank you again for the help. I appreciate it!

 

[mmckenna]

That doesn't sound out of the ordinary. If it's a strong AM broadcast station, the RF gain turned all the way down may not attenuate the signal enough to be noticeable.

Make sure the switch on the back for the antenna is set correctly. INT is for the internal ferrite bar/telescopic whip. External is for the RCA antenna jack.

Touching the antenna will do that on LW and AM.


If the sound is good through the headphones, but bad on the speaker, look for debris in the speaker cone, or loose hardware. I'm betting there's some dirt in the speaker cone or something just came loose.

I'd fix the speaker issue (or use headphones) before passing judgement on the audio quality. I suspect that may be the core issue.
Set the antenna switch correctly, if it isn't already.

There is a small transistor that acts as an antenna amplifier in the radio that can sometimes take a hit from static electricity. It can be replaced if it's bad, but I'm not sure that is your issue.

 

[Boombox]

The DX-440 is a great radio for MW but in many areas (like mine) where the signals are weakened you need an external loop or other external antenna to really get the best out of the radio, especially for DXing.

Also, don't forget. The INT/EXT antenna switch in the back of the radio can oxidize and affect reception. Exercise it a few times. If that switch is oxidized, it would affect MW and SW more than FM, being that stronger FM stations would come in even without the whip.

I don't remember if the RF gain actually works on MW, I never have used it on MW.

Ditto on trying headphones. The headphone jack has a switch, and if it's oxidized, it could conceivably affect the sound.

 

[st25r]

Hi mmckenna, I tried the headphones and when I slightly twisted the jack the audio was crackly. I managed to get it in the right position and listen. While environmental noise was absent, the audio was muffled and scratchy regardless of bass/treble settings when listening to AM. Narrow selection was super muffled. The sound clarity was improved again touching the speaker grille. I could see some fur and hair in the speaker compartment so I vacuumed it out but there was no change in the sound. I guess what I'm trying to say is the radio lets in more noise than signal and the signal is blurry on the AM band. I hope someone didn't make some random adjustments.

 

[mmckenna]

The DX-440 is a great radio for MW but in many areas (like mine) where the signals are weakened you need an external loop or other external antenna to really get the best out of the radio, especially for DXing.

I'm running an end fed antenna on mine. Works pretty well for AM DX.

 

[mmckenna]

Hi mmckenna, I tried the headphones and when I slightly twisted the jack the audio was crackly. I managed to get it in the right position and listen.

That can be from oxidation on the headphone plug, in the jack, or dust in the jack.

While environmental noise was absent, the audio was muffled and scratchy regardless of bass/treble settings when listening to AM.

OK, might indicate a problem with the radio.

Narrow selection was super muffled.

As it should be on narrow when listening to AM broadcast.

The sound clarity was improved again touching the speaker grille.

That is odd that it would do that with the headphones. Might be a that you are grounding the chassis and changing the antenna performance.

I could see some fur and hair in the speaker compartment so I vacuumed it out but there was no change in the sound. I guess what I'm trying to say is the radio lets in more noise than signal and the signal is blurry on the AM band. I hope someone didn't make some random adjustments.

Would be hard to make adjustments to the radio.

But it does sound like something is wrong with it.

Does FM sound OK if you tune in to a local FM broadcast station?

 

[st25r]

That can be from oxidation on the headphone plug, in the jack, or dust in the jack.



OK, might indicate a problem with the radio.



As it should be on narrow when listening to AM broadcast.



That is odd that it would do that with the headphones. Might be a that you are grounding the chassis and changing the antenna performance.



Would be hard to make adjustments to the radio.

But it does sound like something is wrong with it.

Does FM sound OK if you tune in to a local FM broadcast station?

FM is loud and clear. Through the back, I could see an approximately 7" long ferrite loop stick which should pick up stations just as strong as the 4" ones in the other radios. I sprayed some deoxit in the internal/ external antenna switch and moved it back and fourth several times to no avail. The headphone jack cleared up a bit, with the deoxit, but still sounds blurry. This is the second eBay radio I bought that has been troublesome. The first lasted a day and wouldn't turn on after that. At least this one makes some noise!

 

[mmckenna]

OK, if FM is working correctly, then it's likely not an amplifier issue.

Digging into the radio would be necessary at this point. If you can return it for a refund, that might be a good idea. If not, there's the option of opening it up and looking for obvious damage.

 

[Omega-TI]

Used radios (from Ebay) are often like used cars, people get rid of them for reasons, then they become someone else's problem. It's a roll of the dice (gambling).