Opening this Universum CRT 2333C2

[CyberSeb]

Hi fellow boombox lovers,

being a HiFi fan for a long time, I recently fell in love with Japanese 80ies boomboxes. Besides several European units from Grundig (which are a different type and not Japanese ) I already got a Sanyo M7900K and a small Fisher PH 835L. I simply love their look & feel.

So I could not resist and had to take this Universum CRT 2333C2 when I found it for 5€ in a thrift store. "Universum" is the brand name of a German catalog seller, Quelle, which went bankrupt a couple of years ago when they did not manage to fully jump on the internet bandwagon. So their goods are somewhat collectible.

I'm wondering who the actual manufacturer was. The knobs and the overall looks remind me of Sanyo/Fisher or Crown, but I could be wrong. I think the device is from the very late 80ies. It sounds great, and also has automatic track search. It desperately needs new belts on the right deck, however.

The problem is that I simply can't open the device. A friend of mine (who is a mechanic) has failed as well. After removing the screws on the back, I think that the front cover has to come of. As it's still somehow fixed on the top, I think it has to flip/swing upwards.

However, the cassette deck lids are in the way. I have no clue on how to remove them. They're basically one-piece and mounted on the metal axis where the tape deck buttons are attached to.

Does anybody has any idea how to open this puppy? Do you maybe recognize the original model? I would really love to put this baby back into fully working condition and any help is highly appreciated.

Many greetings
Sebastian

 

[Fatdog]

If you are absolutely certain that you removed all screws on the backside, try opening the cassette doors. A lot of times this will help. Also, you will need to remove the knobs - not necessarily the push buttons though.

 

[CyberSeb]

Hi Fatdog, nice to hear from you again!

Yes, of course, I've removed all screws as well as the knobs (only put them on again for the photos). I did not remove the tuning knob (which is attached to the back cover) and the screw for the antenna. I don't think they have to come of. I can wiggle the front cover so I believe this is what has to come off.

Simply opening the the cassette doors does not work. They have to come off as they're too large and are blocking the front cover to come off.

Maybe I will try to also remove the tuning knob and the antenna screw. But I fear that the antenna screw does not have to come off.

This is driving me nuts: HOW did they assemble it?

Sebastian

 

[Fatdog]

Definitely remove the tuning knob. Where does it seem to still be stuck when you are trying to separate the halves? There have been a few boomboxes that have one or more screws on the front that become visible after removing the cassette doors. Any screws on the bottom?

 

[CyberSeb]

OK, I'm a small step further: I found out that the front cover was also clipped on the top. The front cover is now fully loose, and I can freely wiggle it. But I can't take it off because the cassette doors are in the way.

I also found out that the back cover does not have to come off because the electronics and the cassette mechanisms are mounted on it. The small holes on the back (see my picture) do not contain screws. They are nozzles that go into the radio and are used to hold the screws of the components. So removing the tuning know and the antenna did not have any effect.

There must be a trick to remove the doors. Except for the thin acrylic cover they are one-part, and I don't want to use force. I think they would break ...

I have to go to the office now and will try to figure out more later. But at the moment I don't have any clue ...

Sebastian

 

[jimmyjimmy19702010]

The front panel of the deck doors might unclip from the rest of the door (like a Panasonic RX-5500).

 

[floyd]

I can almost guarantee its the back case that comes off. Make sure you remove the screws inside the battery compartment if there are any. I would try removing the back of the box.

 

[Reli]

Nice box! It's an AKA of this:
http://wikiboombox.com/Sears%20304%2021450250

​

 

[MyOhMy]

Very nice box, very nice indeed.

 

[CyberSeb]

Hi all,

thanks for all your kind replies! Reli, you're right - thanks for identifying this boombox and updating the wiki! Was was searching literally for HOURS without success.

So I got it, and I was right! The cassette doors can be removed with some force - see photo.

This was the only way, as all components are screwed onto the back case (except for the speakers).

I've attached a photo from its guts ... The belts look "okay-ish", but the right capstan is stuck (grease). I will now try to clean this up and order new belts. I will keep you updated on any progress.

Cheers
Sebastian

 

[CyberSeb]

So I replaced the belts - I was lucky to have two new 10cm ones. Changing them was not too difficult. I've attached some photos of the drive mechanism. Nothing special, but it seems to do the business ...

Unfortunately, I noticed (of course after reassembly) that the two rubbers of the slipping clutches (which are used to wind the tape in play mode) are brittle, one is already broken - see last image. It has to go onto the black wheel below it.

What a pity that I have to disassemble it again. :'-(

I will head to the construction market tomorrow and see if I can find something that fits.

Sebastian

 

[Fatdog]

A few members, including myself, have had good luck with properly sized O-rings to replace those old idler tires - and O-rings are cheap. Finding one with just the right thickness and outside diameter might take some experimenting, but it will probably still be more expedient than finding a proper tire replacement. If you decide to try the O-ring, scuff the outside perimeter with some fine-grain sandpaper - not too much, just enough to help give it some grip.

 

[CyberSeb]

Hi Fatdog,

thank you so much - that's basically what I did. And I'd like to declare this project as "finished", the radio works pretty well now!



For the record - if somebody comes across this radio - AKA Sears 304 21450250 SR-2100 series (hello Google), here are the parts that I've used:

Belts: 2x 100mm (capstan), 1x 70mm (tape counter).
Idler tires: rubber seals 9x14x1.5mm for union nuts 9.5mm (3/8")

(for the Germans: Hornbach 3820626 "Gummi-Ringe 9x14x1,5mm für Überwurfmuttern 9,5mm 3/8 Zoll", 1€ for 4 pieces)

The rubber seals are a tiny bit too large in diameter (maybe 0.1 mm) which causes the idler wheel to rotate when winding the tape in either direction. Not a big deal: better this than a jammed tape.

I've also tried o-rings. They fitted nicely, but they were too slippery, and I didn't want to sand them down. By the way, they can be replaced without having to take the tape mechanisms fully apart. Simply loosen the screw (on the back side) that holds the idler wheel. It's a bit fiddly, but can be done.

So everything works now. However, I've noticed that there is a minor high-pitched flutter on the left deck, which is especially noticeable with piano sounds. And I can't align the right tape head properly. If the azimuth is fine on one side of the cassette, it's off on the other side. Strange. But I believe both issues come from the non-original parts that I'm using. It's probably a complex interaction between belt tension and/or amount of tape winding. Anyway, it's OK - this is not HiFi equipment. :gathering:

Now I have to continue with my 1994 "Bravo Hits 6" and feel young again (the CD doesn't cut it h34r

Again, thanks to all for your comments!

Sebastian