Diatone jr-711 boombox I've already made a video about that. The volume is steady and low but not changing as the sliders don't communicate with the circuit board I guess, but I have to take it apart first to understand why that's not working. The radio comes on and it can tune but you can't change the volume. This example I got I didn't realize the handle was simply not with it at the beginning as it looked like it had been ripped out of either end. Possibly because this thing is so heavy. The cassette deck is a full logic control system. I'm guessing similar to the jr911 diatone boombox. Maybe I can get this one to work. front Top controls At the top of you see the missing handle where it would attach to and underneath is the input END The other end at the top as you can see is missing the handle where it's attached used to is that's it. Then we have the tuning knob headphone jack speaker out and DC and AC input Back and clean battery compartment. Looks like it never had batteries in there except for the crumbling foam. It's clean here is a close up view of the back sticker Nobody ever takes a picture of the bottom but I do.
Okay opening it up That is the plug for the microphones only from the front This plug goes to something having to do with the controls underneath the cassette deck This plug is I'm guessing the main speaker wires and they all just pull off. No special tools needed I thought I was done but I still have one more plug here to undo. It's a two-wire brown and red goes to the circuit board. I don't know what that's for. Overview of the inside both pieces. The speakers flange seems to be about 8 and 1/4 in really huge. This only runs on 8D batteries so. I'm inside the jr-711 but this looks like the exact same deck from the jr-911 The only thing different is the placement of the one switch at the top and the tape gun is in a different position, but it's the bottom part's almost exactly the same. This gives a close-up view of that even down to the leaf switch on the side. this is the leaf switch side This is the Deck door mechanism side. Looks like two screws to release the cream colored bracket holding the entire cassette deck in its place. Yes it is the exact same cassette deck as in the jr-911. Maybe if this one works I can transpose it with the other one but I'm not so sure for the moment. No, I don't think I'll even try because the wires may all connect differently and all that and it's just right here. Let's get a backside view of the inside of this so you can understand just how complicated this thing looks. This got the radio board on the right and then the rest of it is who knows Okay so next I need to get the mechanism deck out of this plastic shell that is in. I'm not going to bore you with that showing you how it's done cuz you should know what you're doing by now. I know I do. Edit we need to know one more picture close up of these plugged wires from the tape deck And now the gray and brown headwires I think and then some other wired red and white going to the radio. Let's get a picture of that See the upper top left hand side of this picture where the head wires go and then of course the red and white wire going to the radio from the cassette deck
The motor does run. And the belts are okay but the flat belt needs to be changed because it's not quite tight enough because it doesn't transfer enough torque as when the solenoids do work and ask it to change function. The flywheel will stop but the motor pulley will keep turning with the belt slipping. I have it powered up right now with an auxiliary power supply only to the motor but the deck will not be powered from the unit itself. So something is wrong in this jr711, and I'm not putting any more time into it.
Allow me to make a correction as I made one in my 911 thread that the secondary belt needs to be routed this way and I'm going to try to show you without taking it all apart because once you have it apart you'll understand and if you didn't have a belt like I didn't with the 911 this is the way it should go Hopefully you can see that approximately 80 mm square belt as it travels beside each other away from the motor and around the idler and only brushing against the other bigger wheel
People want to know the date to this so let me get you a picture of the motor Those are my leads clipped to the motor to give it power because the main unit won't do it
Okay, I just got to replace the flat belt. Thought I'd show you what the original belt routing looks like before I remove the belts Even though there's next to no sound coming through the preamp, I want the cassette deck to work when I press the buttons even if you can't hear anything. Just an overview picture A close-up shot and one more If you ever take one of these apart the where the pic is, the end that I'm holding or trying to that little tiny white pen has to be inserted into the arm. You'll understand if you take one apart. You must have that little plastic Pin inserted into the arm so all the mechanism works otherwise it won't
Okay, we're measuring the old belt flat I've got 113 mm. I will put on a 105 mm roughly for the flat belt which is the slipping or barely slipping as it's working barely. This is about 92 mm but I put on something just a fraction smaller. Maybe 90 mm or something like that. This is for the secondary belt. Edit. I just couldn't help myself. I just had to find the right belt and put them in here and make it darn thing work even though you can't hear anything above. Barely a whisper but at least maybe the next person could make this work And now we got to go fidgety again and install these belts for the second time in the diatone
Two big 8 inch speakers have to count for something. Full logic cassette deck spells Trouble though. Barely a whisper of sound coming through is a good sign, it's just a capacitor issue for sure, everything is "working" in the signal path just dried up caps that have gone way out of specification. (Though, I am very cynical of boomboxes in general, dismissing the vast majority based on a near certain belief they "all look the same and sound the same... flat bass and depressing".) Man, if you got one of those desoldering vacuum pump tools it would be easy to re-cap stuff like this. You should have got into that years ago. This one comes up as very highly rated and surprising low cost, for example: Hakko FR301-03/P Portable Desoldering Tool with Precise Temperature Control °F /°C
Yes, but I don't have steady hands for soldering. That's why I don't do the really fine work like walkman's. I do have a desoldering pump and I know how to user. It's just a little spring loaded thing. Lastly, I don't have a huge supply of tiny capacitors. I just have mostly ones for power supplies.
Nope. Both tape decks are just different enough on the wiring circuit board to not be able to be interchangeable. The mechanical part maybe, but I'm not willing to go that far with this change over. I thought I'd tried though, so here's a picture of both of them together. Kind of sort of You see on the circuit board in the lower motor which is the 911. There's an orange plug next to the motor and the one that's on the upper motor is wired on for the same function so I can't interchange the them. I'd have to remove. No, I can't do it. Drat. Okay well I've had my fun. I'm done.
