Instructables

PLAY AND RECHARGE IPOD USING OLD BOOMBOX - Hints and tips

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Consider this an addendum to other iPod boombox mods. I admit I borrowed from other Instructables. Not to take away from those Instructables, here is a "shout out" to those that inspired me to dive into my own mod. Thank you.

Instructables on modding an old school cassette player boombox to play your iPod.
Aiwa boombox
JVC boombox
Phillips boombox
Sony boombox

Instructables on building a charger for your iPod.
Super Simple
Famous MintyBoost
YAN9VUSBC
iCylinder

These are all great Instructables. Unfortunately, I ran into some snags and wanted to add a few more features. So, my Instructable covers how I solved some of those problems. I hope this will help others who've run into similar snags or want similar features. Lastly, I had many "do-overs" with this mod and wanted to motivate other modders not to give up on their projects. If you have the courage to tear apart something you just modded, you'll end up with something you can be proud of.

Background:
I started with a Sony CDF-8, an old school combo cassette tape, CD, AM/FM radio boombox. What I wanted in the end is an integrated iPod docking cradle that would both recharge the iPod and play through the docking connector Audio Line Out. I wanted to add a compartment where the old tape mechanism resided. Lastly, I also have a Motorola SLVR L7 iTunes phone so I wanted to add an aux Line In jack.

I've broken this Instructable into segments based on the features I added and the things I learned. I've skipped over most of the basic stuff since the above Instructables do a great job of explaining all of that.

Sorry, I didn't write this Instructable for newbies. The details aren't included. I glossed over things assuming the reader had some previous modding experience. You'll note most of the photos I've included are after the fact. I didn't take any before photos since I wasn't planning to make an Instructable. Without the photos I couldn't include details needed for a neophyte to tackle this mod. Therefore this is more about Hints and Tips rather than a true step by step.
 
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Thanks for the comment. Umm, yes. The AM selector probably could be used instead of the tape. I got rid of my tapes long ago so I had no need for a tape player. Good idea though! Later! : )
smoak1 year ago
Could you rather than losing a tape player section, instead lose the AM station selection? So your selections would consist of cd/tape/fm/mp3?
aompes1 year ago
i have tried this project 5 years eariel then i give up the clean line search and i just plug the head reader of the tape and yeas the sound was noisy
then when i have read your instructubale i was happy that someone have success and give me hope so i opens the boombox ind i searh for the magical line by testing the board with a sound source and bingoooo the sound was so clear and my old dream come true
so thank you because you have inspired me
hafid from Algeria sorry for my English
unknownuser2007 (author)  aompes1 year ago
You are welcome! : )
hey thanks that was a tutorial. i have a problem intalling the aux jack i found the cable which is marked tar,tal.so can u plz guide me.i have attached snap shots of my boombox .two cables coming out from the casset mechanism. thanks
unknownuser2007 (author)  007.sammy1121 year ago
Hi Sammy-
Sorry but I don't know what those markings refer to. I didn't see any attachments either.
Even so, it is difficult to reverse engineer via correspondence. Even with the circuit board in hand, it isn't easy, especially when nothing is labeled. I did this mod to another boombox which I could not reverse engineer. The design was simply too complex for my experience level and tools available to me. I ended up buying schematic diagrams. Which I consider a last resort but not unreasonable since you can usually get them online for about $5.
Sorry I couldn't be more help. : (
jacobsteel1 year ago
amazing!- and yes, this must've taken a _long_ time.... good details, great instructable! thank you
unknownuser2007 (author)  jacobsteel1 year ago
Thanks for the comment! : )
Hey, ive been trying to make my tape player radio "ipod compatible" and tried the tape head techniuqe.Your right,it didnt work too for me,all i hear is static.Guess ill have to try step 1.
unknownuser2007 (author)  mastermakoko2 years ago
Yes, you have to probe around and get lucky. If all else fails, try to find/buy a schematic of your boombox online. I had to resort to this on a similar build. Good luck! : )
goethes2 years ago
nice work! i also got an old JVC stero with CD/FM/Tape. currently i just use a iphone dock and connect its line out to JVC's AUX in. but your work inspired me. :D
unknownuser2007 (author)  goethes2 years ago
Thanks! Post an Instructable on it! : )
scarrazzoni2 years ago
Tried it out and it worked. It was complicated, and I was pretty lucky. I found the right connectors messing around , nothing was labelled. The only issue is that when I select the CD mode and play a CD, sound only comes out from the right speaker. I don't really care as I simply use the AUX input that I created and, sometimes, the radio, which works fine. I powered the boombox with a 12V 2.3 AH battery that beautifully fits in the battery compartment (takes 8 D size batteries = 12V) and then i mounted everything on my bicycle :D. It sounds so well!
unknownuser2007 (author)  scarrazzoni2 years ago
Great! Another boombox repurposed! : )
Kaiven2 years ago
My left and right audios aren't blatantly labeled, though I can clearly see a left and right, I cannot tell which leads connect to cassette 1, cassette 2, or the radio. There are 7 pairs of leads from the input selector and I have no idea what connects to what.
unknownuser2007 (author)  Kaiven2 years ago
I was lucky, my board was labeled. You can connect the power and probe around. The common ground is pretty easy to find. Just be careful you don't short anything or shock yourself. Or to be safe you can purchase a schematic diagram online. I used 911manuals.com to buy one using Paypal. Sorry couldn't be more help. Good luck! : )
I fixed it up! I found two ICs and googled what they were, both were amp chips. I found which one affected the Tape I on the ghetto blaster and hooked my MP3 directly to the IC's input. I had to put 3.3k ohm resistors on both channels, but it now works fine. I can get audible sound with low distortion up to 500ft away!
unknownuser2007 (author)  Kaiven2 years ago
Great solution! : )
drkfox463 years ago
Thank you so much! This really improved my sound quality as opposed to the connecting my ipod to the cassete head.
unknownuser2007 (author)  drkfox463 years ago
You are welcome! I am glad it worked for you. : )
rhonyg4 years ago
Hi, how can I do if my selector switch is digital?
unknownuser2007 (author)  rhonyg4 years ago
Thanks for the comment. : ) Sorry but I don't have experience with a digital interface.
threewheela4 years ago
thanks soo much! your instructions on how to find a clean line helped me to complete a similar mod on an old sanyo radio that looks much like the one in your ible
unknownuser2007 (author)  threewheela4 years ago
Thank you. You are welcome! : )
boris1114 years ago
I'm trying your method by connecting directly to the line in on a Panosonic boombox. I'm not getting any sound out, but my phone does detect headphones.   I'm thinking the boombox needs to detect that the play button is pressed before it will turn on the amp.   Unfortunately I already canabalized the ribbon cable going from the casette to the board on the boombox.   Do you think putting a resistor from the 5 V cassette motor power to ground will mock the play button being pressed?
unknownuser2007 (author)  boris1114 years ago
Oh gosh too bad you removed the ribbon cable. 
I really doubt that the circuitry is sophisticated enough to sense motor movement or motor load. It's just a tape cassette drive but I guess it is possible.

Hmm, what else. Did you find the reed switch I mentioned Step 4, third photo? That may need to be closed/shorted to turn on the amp.

When you switch the function selector switch to radio, does the radio work?

I also ran across an Instructable called "Ghettoblaster MP3 player installation". Check it out because it is a Panasonic mod. You may see something in there to help debug your problem. 

Sorry I couldn't be more help. : (

I figured it out.   I needed to run a short from the 12 Volt power to a label called "Tape H"   First tried 5 volts, but that didn't do anything. 

Sounds great!    Thanks for writing this though.  It inspired me to bring new life to my mid 90's boombox instead of spending $150 on a new  boombox with comparable sound quality.
unknownuser2007 (author)  boris1114 years ago
Great! I'm glad you figured it out. : )
mpikas4 years ago
I see your left and right connections, but where did you connect the ground for the 2 speaker channels?
unknownuser2007 (author)  mpikas4 years ago
For the iPod connector, the ground is either Pins 1 or 2. They can be tied together since they are common. : ) 
Actually, I was wondering on the board in the boombox, where you wired the clean line at the selector switch, you showed the left and right signal connections, but not the ground.
unknownuser2007 (author)  mpikas4 years ago
Oh sorry. On the board it is usually the ground plane. Meaning where the negative is connected from the output of the transformer. The ground plane is common so it is at numerous places on the board. Usually these traces are very fat and cover a wide areas since  designers sometimes use them as a RF shield. Almost all bare metal parts are connected to the ground plane so you can poke around with a continuity meter to find it.
As with most things, I am speaking in general. There are exceptions.
Hope that helps. : )
Thanks, I can find the ground plane, I just didn't realize that you can use it for the signal... I guess that's why old school GM radios are a pain to make work with "standard" stuff since they run a negative signal to the speakers.
endolith4 years ago
What brand and model number is your USB charger?  Are any other pins connected besides the four you listed?

Are you sure the pins are actually numbered and connected like this?  Both 50K resistors are connected to both pins 25 and 27?  Why didn't they just use a 25K resistor?  These pin numbers seem to be reversed from yours: http://www.ipodlinux.org/wiki/Dock_Connector
unknownuser2007 (author)  endolith4 years ago
The USB charger was an off brand with the name of Inspire on it. I don't recall where I bought it. Sorry. I used the audio line pins too in my mod.

Sorry, I didn't realize my pinout links were broken. Here is the new link. Yes, the 50K resistors are redundant. I didn't realize this until later. A single 25K should work. However, it depends on the model iPod. Refer to the link for specific requirements for your model. Yes, the pin numbering is different depending on the connector. There is a note about it on the pinout page.

I highly recommend the PodGizmo breakout connector from Sparkfun. It is large but makes the modding so much easier! : )
nitorud5 years ago
Many thank you's on the post preamp connection idea. I was using a Panasonic RZ-3940 without L or R labels. I plugged my iPod to the ground before the tape preamp and started touching the R to spots that looked promising. Bingo. Now I can crank the iPod volume and the sound is pristine. Thanks for the post!
unknownuser2007 (author)  nitorud5 years ago
Great! Glad to help! : )
GamingRobot5 years ago
Nice im working on a project just like this but im having trouble with static i used the cd linein instead is the tape player linein, does the cd linein have a high inpedence? Also i shocked myself in the project!
turn down volume on ipod, turn up volume on boombox.
unknownuser2007 (author)  GamingRobot5 years ago
Thanks. Looks like you're doing a great job. When you say static, can you describe the sound? Is it like a constant hum or hiss? Is it happening only when you dock the iPod? Or is there static when the iPod is undocked? Does playing the iPod make any difference? There are many possibilities here. Yes, you have to watch what you're grabbing. An easy way of getting shocked is grabbing the bottom of the circuit board while it's still plugged in. Those solder joints are live! Later! : - )
i get like a clicking static sound and its only when the ipod is charging when i unplug the charger within the box its fine no static.
sorry but to add i think i got it mostly fixed because there was impedance miss matching about the same problem you had but i used a t-pad which is a bunch of resistors you can see it here

http://www.instructables.com/id/Boom_Box_Ipod_Dock_Homemade_iHome/
unknownuser2007 (author)  GamingRobot5 years ago
Great! Happy you figured it out! :- )
Macyoshary6 years ago
Mum won't let me do this because she thinks I'll electrocute myself since it says on the back not to remove the case. Is there anything I can do to convince her otherwise?
hahaha ya my mom freaks out when i make fireworks, she doesn't like it when i play with explosives.
unknownuser2007 (author)  Macyoshary6 years ago
Sorry, your mum is right. There is a risk of shocking yourself. When playing with anything electrical, there's always a risk of a shock or a burn. As I mentioned in my write up, this Instructable isn't for modders that are just starting out. My boombox uses house current which is 120 volts in the US, which will shock you. Not something to be playing around with unless you have some experience or supervision .

How to gain experience? I was lucky. When I was in High School, they offered various shop classes. I took them all and learned about electricity in a supervised environment.

Depending where you live, an option are these new TechShops that are opening around the US.
http://techshop.ws/index.html
They offer classes on soldering, welding, sewing, etc. I haven't attended any of these classes but have visited one and was impressed by both the staff and the facility.

The final option that comes to mind is to find a friendly neighbor/mentor. The person always working on their car or has their own workshop is a good place to start.

Sorry, I couldn't be more help.

Ok then. My boombox has house power or batteries, would that make a difference?. Also here in Australia house power is 230-240v which is twice yours. Thanks anyway, nice instructable.
Very nice instructable but I have two questions. first is why did you decide to make your own voltage divider circuit rather than rip it from the existing dock or simply incorporate the the entire dock wiring and just hook it to the incoming power line and then run a switch in the ground wire? secondly what is the point of the 5v regulator instead of running straight from the 10v motor line if you are using the 12v input? It would charge faster that way.
Thanks! :-) 1. I'm guessing, but I think the newer firmware for the iPod knows when you're not connected to the computer that holds your iTunes library. That's the reason for the pull down resistors (voltage divider network). The iPod firmware looks for those if you're not connected to your computer. Also, the harness that comes with the iPod doesn't have the pins for the audio line out so you need to buy a new Sparkfun connector if you want to play AND recharge using a single connector. The Sparkfun has all 50 pins. :-) 2. Good question. I never attempted to test if the 12V Firewire circuit would charge the iPod from a 10V power source. I just assumed that it wouldn't. Silly me, I should have tested it before building the 5V regulator circuit. :-) Hope that helps! :-)
endolith6 years ago
Uhhh... Your speaker is an input?
unknownuser2007 (author)  endolith6 years ago
Okay, I fixed the block diagram. Thanks!
Vermin6 years ago
Excellent instructible. Only one (very minor) flaw: the Power amp and pre-amp triangles in the block diagram are back-to-front. The pointy end is usually taken as the output.
unknownuser2007 (author)  Vermin6 years ago
Doh! Of course, you are correct. I'll fix it when I get a chance. Thanks!
robogobo6 years ago
Nice post, but next time try not to be condescending toward new folks. The fact that you didn't document your project has nothing to do with a person being new or not. We like newbies here. Most of them have alot of knowledge to bring.
unknownuser2007 (author)  robogobo6 years ago
Thank you for commenting, I appreciate it. Darkcloud is correct in what I was trying to say. I apologize if I've offended anyone.
He wasn't talking about people new to Instructables, he was talking about the people new to modding.
I've been planning on doing something like this on my current stereo. This is a good instructable to remind me to get off my ass and do it lol.
unknownuser2007 (author)  Erik Lindemann6 years ago
Thank you, glad to inspire you!
andy606 years ago
nice instructable!!
unknownuser2007 (author)  andy606 years ago
Thanks!