Panasonic ED77 modernisation

[samuelellis]

I know this doesnt have the same allure and style of a 80's boombox but i remember when it came out when I was in school and i thought the motorised top was the coolest thing ever.

So when i got one for free with broken tape decks i couldnt say no.

However two problems, when I say broken i mean destroyed, someone had tried to fix them in the past and just wrecked it to the point where i would have to find another one of these to pull the mech out of that and the system and then do the belts and it just isnt worth it, I will be salvaging whatever parts I can from the ruined deck to sell on cheap and doesn't have an Aux-IN

So the first step was finding where Audio can be fed in, with some help from this forum and the wiring diagram I found that it looked like you could tap into the MIC input

The next step was to disassemble it and test that theory and success, I was able to feed an input from my desktop DAC into the input. The next step was to clean it as it had a good 15 or so years of dirt and finger grease - if my wife asks i did NOT use the dishwasher for that task.

While it was in pieces i wanted to jazz it up a bit so i sprayed the speaker ports and the speaker grills into blue and then sprayed a metallic flake lacquer over it

So what is the plan for the broken tape deck area. Well what i have in these pictures are is a RaspberryPi running volumio, it is connected to a 7.9inch widescreen display and a Pi-DAC. for a test fit is almost perfectly fits in the space the tape decks took
In testing this i was feeding it into my home stereo (Cyrus Pre amp, Cyrus power amp per speaker and a pair of 40 year old hand-built speakers) and it sounded bloody good.

The next steps are to
-Design a 3d printed bracket to hold the screen in the location the tape decks were and get it printed
-Cut the plastic for the tape deck to give me the dept the mount the Screen/Pi/DAC sandwich
-Install the 3d printed bracket. I think this will be a case of fitting and car body filler to make it look smooth and OEM
-Tidy up the bodge wires on the main board for the aux in
-Measure up and make some posts to support the main board replacing the ones lost from the tape mech removal

 

[goodman]

This widescreen looks so cool. I waiting to see next steps in this big project. Good luck in customization.

 

[caution]

Next level stuff, excited to see the result!

 

[samuelellis]

Ok so this is what I have done so far.

During testing of the boombox before it was taken apart i noticed that the power LED dimmed at full volume on hard bass hits, this suggests the PSU for this is struggling.
My plan originally was to find somewhere I could take 5V from the board to power the raspberry pi/screen but as it looks like it struggles im not going to do that, shame because if i could have tricked it into thinking it was always playing it had a nice 12v output to the tape motor i could have stepped down
Luckily on the back of the PSU I have nice big chunky terminals so I can solder some mains rated cabling from that and find somewhere in the system to house a small 240v to 5vDC adapter
I am also removing the tuner board entirely, it gives me more space to work with in the device and it is less of a load on the main PSU

In regards to speakers, the original ones are still in god condition - I did think of upgrading them but they are 3ohm, swapping to 4ohm would not be an issue usually, just sacrifice a bit of amp power but as this only has 7.5Watts to play with im just going to stick with the standard speakers, for its use case as something to listen to when washing/valeting the cars they will be good enough

So the bit im sure a ot of people are interested in, how the hell am I going to mount the screen. As you saw i plan to put it where the tape decks were but I dont want to lay it flat so i can avoid reflections. Because of that I have thrown the following together. Its multi-piece but this gives an idea.

The top part is just a simple shape with a hole cut into it so it will fit into the space the tape deck doors used to sit making it flush
The next part is basically just a hollow box with a lip that should slide into the top part and down
In managed to find on a CAD site someone who had already modelled a case for this screen so I was able to grab the model, chop off the bits i dont need and set it it into the box. The idea is that it is set at a 22degree angle towards the front of the unit to make it a bit more resistant to reflections and also, it just looks cooler.

Those parts are on the printer now so once they are done I can see what they are like. My idea finally is to print it in a plastic called ABS - this will met me vapour smooth it so it looks like a injection moulded part but im making sure that is a day im not working as the printer is in my home office and ABS fumes are really not good for you

 

[samuelellis]

Couple of small updates
Test print for the screen mount was sucesful
Part one goes into the gap where the tape deck doors used to sit - looks a bit rough but i was a but hard with the edging tool after it came off the printer
Part two goes through the hole and takes the place of the tape deck. As you can see the screen fits perfectly - went with a 10degree angle instead of a 22 degree angle just so i didnt take up too much space in boombox. To make it fit properly i need to trim some plastic out of the boombox - this was to be expected

Currently reprinting at a higher resolution ready for fitting

 

[samuelellis]

Starting to take shape now, still need to do some trimming of the OEM plastic.

I was going to do the bracket in ABS and paint it but i found this blue filament that is almost a match for the blue paint i used on the ports and the grill so need to power the pi and screen up in it and soak test it for a day or so to make sure it can handle the heat.

In regards to controls i gave that some through - if i leave it on tape then the boombox does nothing as obviousy it doesnt have a tape deck and ignore button presses so I can solder patch leads onto the back of the front control board and wire them to the raspberry pi to control play/pause and track forward/backward and make the OEM controls operate playback as well

Still got that stuff to do

 

[samuelellis]

Guess who messed up his measurements so when the cobra top was put back on it would not close.

This does mean i needed to do some re-design but it now fits. As the plastic ive printed it in is called PLA it can be susceptable to heat so im going to let the pi sit and play for a bit .
I know in previous testing the pi can idle around 68ish deg centigrade doing this but that was in a sealed box (a home hifi project im working on as well) so i just want to see if this will be OK or if i need to reprint in more heat tollerant material. It does look cool however