I created an account to show you guys this:
My donor Boombox
The port extensions to the back of the case.
Attaching new “line in” wires to where the output of the cassette deck’s preamp was.
The raspberry PI installed in the case.
To the left is a mains-to-usb power adapter soldered onto the existing powersupply.
Anything luminous orange you can see is courtesy of my 3D printer.
And I have been playing music all day from it flawlessly 
Amazing! Like it a lot! And love the way you made this relic a bleeding edge boombox!!!
Do you mind if I post it in front page on blog?
Sure thats fine
I have some other pics of the build process around too if you want.
I plan on doing a similar build using the Wolfson Audio Card. I have a few questions:
Does the cassette player still work? If so, how did you connect the sound out from the cassette to the pi?
What DAC are you using?
Does the pi power off and on using the boom box power button?
Did you replace any speakers?
Thanks!
Sorry for the slow reply, I thought I had notifications set up on the thread, but clearly not 
No, I decided to replace the cassette functionality completely. You could keep both by adding a switch on the line in to select between cassette and rpi though.
I am not actually, just the 3.5mm headphone jack. I was thinking of changing to use a DAC, but the sound quality on the Hifi itself is not the best as is, and a DAC might be a bit of a waste for this particular build.
No, although I have been thinking about this - I actually am using the Play button on the Cassette deck to trigger power on the rpi.
No, asides from the cassette deck replacement, the entire machine is stock.
Was it tricky to work out where the audio out wires from the tape mechanism were so that you could tap in the output from the pi?
I have a 14 year old Panasonic portable that would be an ideal project…
Not especially, I looked around for a chip on the circuit board near where the outputs from the cassette connected, and then googled the IC numbers on the chips until I found a pre-amp one. Then just a case of matching the pins to the inputs.
Nice concept. Amazing design and raspberry factor is wow. Totally like it. Surely, i will use this concept in my rechargeable boombox project. Thanks for sharing.
Nice concept. Amazing design and raspberry factor is wow. Totally like it. Surely, i will use this concept in my rechargeable boombox project. Thanks for sharing.