A little help needed for a simple issue

[Ageispolis]

Hello all, new member here (enthusiast not professional). I have this wind up radio that I would like to put an input on so I can play my ipod instead of listening to the weatherband (or FM/AM if need be). Last night I took it apart and found the main chip's datasheet online, and because its mostly in Chinese, I can't know for sure what I'm doing (the chip is a CD1691CB btw). Anyway, here's what the sheet says for all 28 pins

1 MUTE
2 DISC (FM)
3 NF
4 CON (VOL)
5 OSC (AM)
6 AFC
7 OSC (FM)
8 OUT (REG)
9 RF (FM)
10 IN (AMR)
11 NC
12 IN (FMR)
13 GND (FE)
14 OUT (IF)
15 FM/AM SW
16 IN (AMI)
17 IN (FMI)
18 NC
19 METER
20 GND (IF)
21 AFC/AGC
22 AFC/AGC
23 OUT (DET)
24 IN (AF)
25 C (RIP)
26 V (CC)
27 OUT (AF)
28 GND (P)

I found that connecting the two wires from my jack to 28 and 24, I get good sound but it might be killing my battery pretty fast. Is there a better way to do this?

 

[davenn]

I tried all the usual datasheet suppliers without luck can you supply a link to where you got your datasheet from please

I would suggest that you should be feeding your signal into the amplifier stage of the radio not the receiver/IF/detector chip.

so you need to see where pin 27 (audio out) goes topossibly the volume control.
that would be a better starting point

cheers
Dave

 

[Ageispolis]

Thanks for the reply. The link I used is (http://www.datasheet4u.net/download.php?id=612954).

Here are a few pictures of the two boards. The smaller one has the volume control, and the larger one has the chip. Pin 27 goes to the yellow box (diode?) on the larger board. The signal doesn't really respond to it.

 

[davenn]

yeah ok

that was one of the sites I went to, the pdf wont show anything for me just a blank document who knows why ??

Anyway..... forget about the chip, that yellow thing looks like a ceramic filter, a weird thing to be hanging off the AF out maybe you miscounted the pins started at the wrong place on the chip ? dont worry

get back to the volume control.... in the 2nd pic there are 3 solder terminals in the middle of the board I circled in green....

the middle one appears to go to that yellow wire to the left... where does that yellow wire go to ?
one of the other 2 will/should go to negative rail, the other one will be signal in from that other board. thats the one you want. Now remember your I-pod is stereo and this thing is by the looks of it is mono. So using just left or right channel from the I-pod you should be able to connect to that vol control between the signal in and the gnd/negative lines

I assume there must be another circuit board with a small amplifier chip on it to feed the speaker ?

cheers
Dave

 

[(*steve*)]

That is amazing. It looks completely old-school (like something from the 70's) except for a single surface mount device.

It looks to me like pin 24 is the input to the audio amplifier.

If that is true then you could inject your ipod signal into this pin and have a wind-up ipod amplifier.

Next trick is to have a wind-up ipod.

 

[(*steve*)]

the pdf wont show anything for me just a blank document who knows why ?

You need the Chinese font pack. Then it magically appears with an incomplete looking block diagram

 

[Ageispolis]

The yellow wire from the volume control goes to pin #4 (CON VOL)--haha. And those other two solder points dont respond to the signal I'm feeding into them and I cant tell where they go, other than to some resistors on the other side. There are no other boards that look like they might be of use. But there are two more (one for the headphone jack and one for the solar panel.)

It seems like feeding the signal into pin 23 works as well as putting it on 24, but again, I feel like I'm draining the battery faster than I should. Am I imagining this?

BTW, this little radio is cheap ($20) and I found another almost identical version on the net in case anyone is interested in this kind of project.

http://www.amazon.com/Rothco-80004-Solar-Wind-up-Radio/dp/B003U0BCRW

 

[davenn]

You need the Chinese font pack. Then it magically appears with an incomplete looking block diagram

ohhh ok, I have always been wary of adding unknown sourced font/language packs
viruses etc mite give it a go.

he said he tried pin 24 but it was killing the battery fast
BUT he didnt say which battery, the Ipod one or the radio one

D

 

[davenn]

ok.....
having now seen the datasheet

pin 23 detected audio out goes into pin 24 audio in to amplifier stage. audio out from pin 27 to speaker.
there's an audio out of pin3 via vol control and back into pin 4.

you would easily overdrive the signal level into pin 24 from the Ipod. it would have to be set at the lowest volume. Why ? ..... cuz the recovered audio from the detector pin23 is going to be very low going into pin 24

ok Ageispolis, point to consider. The total power disapation of this chip is 700mW
so at the most you are going to get 500mW at the speaker. and its mono to boot.

If you really want something respectable for you Ipod to use in your room, why dont you just get a set of amplified computer speakers. most of those are rated at ~ 5 - 10W per channel. Would make a great amp for you Ipod, mobile phone music playing etc

is just a thought I think you are likely to be unimpressed with the results of trying to use the tiny little amplifier in this radio unit.

cheers
Dave

 

[Ageispolis]

Dave,

The whole point of this little setup is to be able to play mp3s while camping/backpacking. This seems like the most compact way to do it. I know the sound isn't great but its better than some earbuds, and being that there are solar powered ipod chargers out there, I can take it all out with me and it will still be smaller than anything else I can use and I wont have to worry about batteries either.

I'm not understanding why the volume level would have to be low since it is going from 23 to 24, and I'm jumping in at 24. It sounds fine when I tap in. But again, (I'm not really understanding this completely), could I be draining the amp battery faster this way than just listening to the provided radio? It seems like so.

 

[davenn]

Dave,

The whole point of this little setup is to be able to play mp3s while camping/backpacking. This seems like the most compact way to do it. I know the sound isn't great but its better than some earbuds, and being that there are solar powered ipod chargers out there, I can take it all out with me and it will still be smaller than anything else I can use and I wont have to worry about batteries either.

yeah ok you have to unserstand its an extremely low power amplifier in that unit.
You would almost get the same volume level just putting the output of the Ipod straight to a couple of speakers.

I'm not understanding why the volume level would have to be low since it is going from 23 to 24, and I'm jumping in at 24. It sounds fine when I tap in. But again, (I'm not really understanding this completely), could I be draining the amp battery faster this way than just listening to the provided radio? It seems like so.

Because of what I said in my previous posting....

"you would easily overdrive the signal level into pin 24 from the Ipod. it would have to be set at the lowest volume.
Why ? ..... cuz the recovered audio from the detector pin23 is going to be very low going into pin 24."

The normal level out of pin23 into pin24 is absolutely tiny, much much lower than the output from the Ipod. Therefore it will be VERY easy to overdrive the input to Pin24.
The mismatch between the output of the Ipod and the input to Pin24 may possibly be what is causing the Ipod to draw more current and hence flatten its battery faster.
cant confirm that without doing some tests.

Dave

 

[davenn]

I would also be interested to know...
How much voltage the solar panel on the radio is producing.
with the radio switched on and operating normally, measure the voltage from the panel

Dave