Degen / Kaito 1103 jog dial then S-meter dies, fixed both

[mitaux8030]

Like some others, my jog dial operation became erratic, so I opened up the DE1103 and squirted a bit of electronic quality contact cleaner into the jog dial mechanism, and noticed the jog dial wires at the plastic header plug end looked a bit less than ideal, so I carefully pulled the header pins out, reterminated the wires and reinserted them, as well as strengthened the arrangement with a bit of heatshrink over the wires.
(I wouldn't recommend doing this unless you've got good magnifying glasses, very fine tipped soldering iron, really fine needle nose pliers etc)

After reassemby of the radio, I noticed the DE1103 signal meter no longer worked. The DE1103 was still as sensitive as ever, and would scan and stop on signals as normal, and the battery meter function still worked fine.

The problem turned out to be the flat ribbon cable that joins the two circuit boards together. I'd used a pair of very fine needle nose pliers to insert the ribbon cable into its plug on the CPU circuit board, and in doing so had pinched/bent one conductor close to the 'free' end of that cable. Straightening out the ribbon cable and carefully reinserting it with my fingers only solved the problem.

If you've an unexplained S meter failure on your 1103, after recently tinkering with its insides, take a look at the very delicate ribbon cable and see if its pinched or bent or has a bit of contaminant on the contacts at the 'free' end. One other (unlikely) cause of failure further down the track could be the 10uF electrolytic capacitor on pin 7 of the TA2057N IC - if that were to go short circuit, the S-meter function would definitely fail and likely also have an effect on AM/SSB reception too.

 

[gipsybar]

Hi mitaux8030,

I see that this thread is 3 years old but I'm still writing to you because I can't manage to find any other useful resource about the s-meter of the Degen DE1103 receiver.

My problem: I've got this receiver from 2 weeks and I bought it new. It's working fine, except for the s-meter which seems to be "lighter" than the other things on the display. I mean that the signal bars are difficult to be seen (it doesn't matter if you look perpendicularly on the screen or from a different angle), while the numbers of the frequency, the orizontal bar and the other things are all clearly visible. Moreover, I've seen many videos on Youtube in which the s-meter is dark and perfectly visible exactly as the rest of the other screen informations, so I deduce that it's my own device's fault.

My question: do you have any suggestion for me about fixing this issue? Should I try to look for the ribbon cable that you mentioned, even if I didn't modify anything nor open it?

Thank you for the attention, I hope you can read and answer this message.

Regards.

 

[mitaux8030]

If your DE1103 is only two weeks old, I'd return it for refund/exchange.
If that's not an option, unfortunately you may have to live with it. The S-meter display is part of an integrated LCD unit, and shares all common circuitry with the rest of the display. Either the LCD itself is at fault, or more likely IC8, an SJP72N4 MCU is at fault. Neither would be economic to replace ie it would be easier to replace the entire radio.
Two easy things you might try is confirming all the PCB to LCD connections are good, and that there's no dry joints around the 100k SMD resistors going to/from the LCD display. Its been a while since I had the 1103 open, so can't recall if the LCD is directly soldered to the PCB via pins, or wether it's connected by one of those funny conductive rubber strips, or some sort of flexi-track. If there's any screws holding the LCD down, try tightening those just a touch. Don't overdo it, as that may crack the LCD and cause it to 'bleed'.
Sorry that wasn't much help, hope you get it sorted.

 

[gipsybar]

Thanks a lot for your help, mitaux8030. I am a little worried about opening it but maybe I'll find the courage and I'll check all the things you indicated me. By the way, since it seems that you are experienced with these kind of things, why don't you check out this page that I found Google Traduttore (it's translated from Russian with Google translator), which contains a list of modifications for improving the Degen 1103.

My receiver is new as I already said, but I bought it from China (no one seems to be selling it here in Italy neither in the rest of Europe) and so it would probably be not worthy to act for having it replaced, specially because everything else works very well.

Anyway, if I'll do any progress, I'll share it here.

Thank you again.
Regards.

 

[gipsybar]

More details on some strange behaviours of the display of my receiver.

Thanks to a "discovery" that I've just made, by pressing the VOL button the lcd shows the battery charge indicator, but all the bars are correctly visible only starting from an angle of view of approximately 170°; at about 130° I can see that only the first 2-3 bars from the left are dark, while the others seem to become gradually more transparent from the middle towards the last on the right; from a lower angle till 90°all the bars become totally invisible (the reason why I didn't even know the existence of this feature, aside from not reading the manual carefully ).
The key symbol of the HOLD function, if the function is not activated, is visible in the same ways from the same angles of view that I've just described.

Instead the numbers of the clock/frequency section are Ↄ8:88 (a reversed C like followed by three 8) from an angle of view of ~130° to ~170° .
At certain times some segments of the 8 digits blink together with the dots of the clock, but these blinking segments aren't never the ones involved in the representation of the numbers of the actual time.

Last but not least, if I don't do anything, the bars of the s-meter/battey indicator from an angle of view of ~170° look as follows:
-the first 2 from the left are dark;
-the third and the forth from the left are more transparent than visible;
-all the other bars are completely invisible.

 

[Boombox]

Dumb question time: are you using fresh batteries, or an AC power supply? Some LCD readouts like full batteries.

Dumb question #2: Do you notice a difference when the room temperature changes? Some LCD readouts will act up a bit when it's very hot or very cold. I have a SW digital portable from the 90's that has an LCD readout that goes a bit darker than usual when it's hot, and when the radio's cold (like under 45-50 degrees F) some of the elements on the LCD don't go dark enough.

When it's regular room temperature, and the batteries are fresh, the LCD's fine....

It's entirely possible that Degen readouts don't have these tendencies, but I thought I'd mention it just in case....

 

[gipsybar]

Hi Boombox, thank you for suggestions, which for sure are not dumb

1)I'm using 4 fresh Sony AA rechargeable batteries of 2700 mAh because they last much longer than the ones provided with the receiver, which are only of 1300 mAh. I recharge them with an external Sony recharger because it is very fast: infact it takes only 5-6 hours to completely charge four 2700 mAh batteries, while the radio, even if it's capable of acting like a recharger, takes more than a day to accomplish the same job. And more, the Sony recharger does also remove the memory effect if present and monitors the batteries one by one, stopping the charge when they are ready.
I've not checked if the LCD behaves at the same way when using the Degen batteries, but I'll do it as soon as the current batteries discharge.

2)About your 2nd question, I don't have an answer because I own this radio from less than a month and here the temperature is always quite high, 30°C today, so I think I will be able to do such a comparison when this winter comes.

Please feel free to give me any further suggestion.
Thank you.

 

[Boombox]

It may be that your radio has a poor connection to that section of the LCD readout, like Mitaux8030 mentioned. I just saw a pic of the 1103 (I've never seen one or tried one) and it looks like it's a complex LCD readout.

So I suppose it's a matter of whether the signal strength indicator 'glitch' is something you can live with, at least until you can fix it.

One of my favorite digital portables has a next to useless signal strength indicator (basically three bars -- and any noise level at all will give it two bars). Two other radios just use a red LED, which light up when the IF chip sees more than 25dbuv (whatever that really means)....

With those radios, the 'signal strength indicator' I use is my ears.

With a couple other radios -- which have more bars in their readout -- I still use my ears to estimate whether a signal is S3 or S5, because they don't always react the same way to a given signal.

 

[gipsybar]

Yes, I think the LCD should have quite complex connections to understand and check, at least for me.
Obviously it is quite clear when a signal is strong or poor, but I'd like to have an objective indicator, specially because I'm a newbie in SWL and BCL and so I'd prefer to have at least a certain level of reliability for sending reception reports - activity that I would like to start soon. Even if the S-meter of the Degen DE1103 is probably not the perfect one, because it consists of 9 bars which are divided into 5 groups and so they should be considered as 5, it would help if it worked.
But in the end, I don't care a lot about it because all the rest works perfectly

* Little question off topic: you spoke about the IF chip, can you please explain to me what it really does? Does it work like a filter for frequencies? Because I had this impression from what I've experimented with the wide/narrow band selector of my radio. *

Thank you Boombox.

 

[Boombox]

The IF chip is the chip in the radio's circuitry that contains the local IF oscillator and mixer circuits; the IF amp(s); detectors for AM and FM (if the radio has FM); a connection for LED or LCD signal metering; a connection for a stereo indicator, an FM mono / stereo switch, etc. -- and sometimes an RF amp and AF amp are also thrown in -- all depending on the chip.

Radio manufacturers started using them sometime in the late 1970's to reduce parts.

Some shortwave digital portables have extra circuits in front of the IF chip to improve performance -- the Sangean 909 / Realistic DX-398 is an example. They have several IF stages in front of the IF chip, including the wide and narrow filters. I don't know if the Degen 1103 is set up that way -- I've never seen a schematic for one -- but it's possible..

I'm guessing that the wide/narrow switch in your radio would probably be in front of the IF chip, and if it's anything like the circuit in the DX-398, it's probably a switch between two different ceramic filters, and the signal then goes into the IF chip for a final stage of amplification, detection, etc.

I'm sure others on this board know a lot more about this than I do, and can probably explain it better.

Hope it helps, though.

 

[gipsybar]

Thank you for the explanation

 

[gipsybar]

LCD fixed!

Hi guys, I've got good news: I've fixed the display of my receiver
I finally found the courage to open it and do some check.
Since the front and the back are linked together by three connection cables (one for the speaker, one for the LCD and another one which I don't know what it really does), I limited my intervention to only pushing/moving these cables and their connectors while checking the results on the display. After doing so for a while, magically the faded parts of the LCD become 100% black! Though I'm not able to say what the problem was. Infact after seeing the positive result, full of happyness, I immediately reassembled the receiver with the screws, I turned it on and sadly realised that the problem was returned again. So I had to re-open it and play with the connections once more to make the ghost parts become black again, this time checking the LCD after putting every single screw.
Now it's functioning good and I really hope that the fix will last.

 

[Boombox]

I'm glad to hear you fixed your problem!

Sounds like the connector in question was just a bit flaky -- maybe it wasn't secured enough at the factory.

Hope your fix lasts.

And at least you know what the problem is now, so if it happens again it will be easier to come up with a permanent fix -- if that is ever needed.

 

[gipsybar]

Thank you, Boombox. The fix is lasting for the moment and I'm happy with it. I have to say that having a working S-meter has revealed to be more interesting than what I thought, because it lets me better understand and compare the different signals I receive. For example, I found that two signals which seemed to me to be one more strong than the other, actually had the same signal strenght on the S-meter and so the difference I felt should be due only to noise, fading or other propagation defects.

The Degen DE1103 S-meter probably isn't the best one around, but for sure it is better than not having one! ;-)