Universum CTR 2236 and Sharp GF-9292

Couple months ago I got a nice Universum CTR 2236 mini boombox. There is a sign "Quelle international" on the back, probably meaning that it was sold through mail-order catalogue or shop by that name. Quelle was popular in Germany during 1960s and 1970d, but I could not put exact date on this box. Here are the pictures before cleaning and restoration job:







To make long story short, I got it cleansed, the belt replaced, and it worked really nice for small box. But, now the plot gets a twist.

Several months before my friend dropped off this one on me, I got a glimpse of Sharp GF-9292 at one location.

The thing was, the 9292 was in one company, sitting on the same floor, playing local radio. It was used non-stop from 1983 (or something lite that, nobody could say exactly) until yesterday. When I saw it, I new that her days were numbered.

The tape buttons did not had any effect, volume and other pots were, as expected, scratchy and contacts were not reliably switching. Also, tuner was drifting and the right channel would die after 30-60 second after she was engaged. Yes, the days were numbered.

Yesterday was raining like... pouring. I was happy to get there and tried to be fast, but it took me two hours, across the mountain. There were leafs and branches on the road, rocks and mud. Funny thing, when I was there several months ago, there was also a storm on that same road. But yesterday, even police patrol pulled me over for a check. They probably saw that I was only one on the road during, driving during the storm across the mountain, only a madman would do that... Did I mention that there is no cell reception at all for at least 60 out of 80 km of that trip. Just 10 km from city, you get so enclosed in mountain that radio reception gets weak.

After arriving I had interesting situation. Some 30+ people working there could not come to agreement if they would just give her away or shall I get them something instead. So I offered my old home theater 5.1 system, above mentioned "Universum", or just some money. Guess what, they did like CTR2236 better. Shall I just mention that there was never a trace of this home cinema model on LG internet pages? But they did sell



Finally, after I got this GF-9292 in the trunk of my car, clouds dispersed, sun was shining, and here are the pictures of my GF-9292:


There!


I do not know what kind of gunk this is, but looks like some glue.


There is so much dust inside grills.


I am going to need two areials for GF-9292...

Great back story, after 30yrs+ of the BB sitting in the same office there'll be some long-term employees looking at the old BB space for months thinking how weird the space now looks, some things you just can't get used to.

That 9292 will clean up well judging by the pictures. Finding the sleeved aerials might be a pain in the ass though.

I remember that we had a Quelle catalog (or "catalogue"), big, thick, printed thing. Can't remember seeing many (or any) Universum sound systems in that volume, though. (Not that this under-age-13 kid was often browsing boomboxes in catalogues, I shrug.)

I'm inclined to say that the interior of the Universum CTR-2236 doesn't look much more complicated -- that is, scarier -- than that of an Aiwa CS-600U. But that's ironic, seeing that I fumbled the repair of my own STEREO 600.

Anyway, capacitors and cams gears aside, don't think I'll trade in my Aiwa for this Universum. This model of this European-market brand has no tape counter. I tend to think: better have a tape counter. But I do commend HRmeteohub (and other boomboxers) for the skill and will to open up these sound systems and render them useful again.

.. just to get back on the topic.

My daughter and I are cleaning the 9292 from 1980., and it is coming nicely. I had found in my stash square belts, but I will have to order a flat belt for tape deck.
Just as Hisrudness said, sleeved aerials = Auch!

Also, since she is disassembled right now, may I ask for an advice? I do not see any capacitors blown or leaked, but would you recap the board anyway?

I would say recap the 9292 if you are comfortable with the process - and have the time.

That score was so well worth your perseverance! Congratulations on it!

The plastic is out of the bath, Goeff provided me with sleeved antennas an flat belt that was busted, and some capacitors are getting replaced. Unfortunatey the door was not dirty or gunked with glue, but the clear plastic was melted with (acetone I presume) and than severely scratched. Badly.
Now, I could sport some more $$ for another door or try to make it better. First step would be, in my opinion, taking the plastic away from metal part. Unfortunately it is glued and the glue hold on like I can not believe.

How doI take it off?
- solvents will only make my problem workse as they will melt the acrilyc door as well. Not all of them, but I doubt I can get it behind the metal all the way around
- forcing will not help, that I am positive
- perhaps if I microwave it for 10-30 seconds?

Try a heat gun, and then pulling fishing wire between the door and the metal

Thank you for the advice, I'll try that.
As a first test I took a Mini-drill, set on low speed (3-4000rpm), with small metal brush and tried my luck on centrally located damage.
This the first result. Not perfect, but a step in right direction.

So... I took my time with this small steel brush and it looks better. One should be careful not to keep it too long or press too hard on one spot. If you do that, the plastic will start to melt, and that is bad. It is not hard to detect this, as this plastic smells really bad, and the moment you smell it, this means you destroyed a layer and it is going to look scratchy = bad.


Before:

View attachment 43402


The changes are small but visible, and I keep telling myself: be patient!




And here is the mini-drill with brush on it:

I finally got some free time to work on my 9292X.
First, I have tested the radio. After disasembling, deoxing the switches, pot's and trimers, washing the box and cleaning every switch, socket and jack, I had to replace belts, pinch roller, and repair power cord. Now, the first round of testing has begun. So far, she works as it should.


I had my doubts about capacitors, so I pulled couple that are on the signal path and tested them, but they are all fine. I am positive that she worked 38+ years constantly, so any other caps don't need reforming, because they are not powered up only since autumn. Perhaps in the future, but now the 9292 is as original as it could be. But, I can't shake FatDog's advice, so I bought a bunch of caps and they are ready in my drawer.


And there are those tape door... The plexy was pitted and scratched, with deep burrows. As you have seen before, I have sanded and partially reconstructed the surface, but there is no way I can finish it without removing the alu front plate - decoration on the door. After trying the microwave, the hot air and some other stuff, it would not budge. Finally, I got myself together and pulled it away using thin knife blade, fingers and lot of patience.
At first, the front plate was a bit curved, but it is so soft that I got it straight just with light pressure.


After inserting the knife/scalpel blade at the bottom between the front plate and plexiglass I got it partially detached.


This should be done slowly and with care, or you could bend or break soft alu plate beyond repair. The weakest point is where decorative bolt is going through plexiglass.


Athe there it is, finally detached. Now I have to remove traces of the 35+ year old glue. There are traces of glue on both alu plate and plexiglass.


I used a fine sanding sponge and mini drill with steel sanding brush. Some small amounts are left, and I'll deal with it right after posting this on BB page...

Good job mate. Looking forward for new posts. I m still searching for local electrician who would open and clean mine 8180 and change belts.. no luck so far.

Lol just now I noticed we are "neighbours"! Pozdrav iz dežele

I can't wait to see more progress on this, HR.

Alpha Mike said:

Good job mate. Looking forward for new posts. I m still searching for local electrician who would open and clean mine 8180 and change belts.. no luck so far.

Lol just now I noticed we are "neighbours"! Pozdrav iz dežele

Click to expand...

Mike, I am going to Zagreb this sunday, we could meet if you are near and I could do that for you. Just drop me a PM if you are around.
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I have noticed that the colour is badly worn out close to volume pot-sliders. Could I get someone to help me choose correct metallic gray colour?

Or should I just go to car paint shop and ask them to mix something for me?

First test. Pots and switches are ok, but there are still some things to clean, like buttons and some crannies. I have bathed it and washed it with cloth and toothbrush and still some dirt remained. Both antennae are in place (as nikonfoo has said - expensive hobby), belts and pinch roller are new, and...



It turns out that there is a rubber roller driving left tape reel and it is slipping. it looked ok, but it is worn out, and I have to get a new one. Besides that, BB is working nicely. After the cleaning it is obvious that there are several points where the usage is visible. The color is scratched and I am considering painting the case in some colour. There was a nice one in red on this forum...

Furthermore, I was at my local car paint shop and they gave sold me a plastic polishing paste (looks like toothpaste, and probably has similar composition ) I have already sanded the door with 500, 1000, and 5000 (wet) sanding paper, plus some polishing with mini drill (coarse cotton attachement). I guess that paste is my next step.

@HRmeteohub I used same paste on my TRK on FM scale and cassette door. It works great. I used it with turtlewax fine polishing cloth.