Electronics > Repair

Blaupunkt Barcelona 2340 - Radio 1956/57.

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DrG:
I am now the proud owner of this fine piece of equipment.



The schematic is here https://elektrotanya.com/blaupunkt_2340_barcelona_s-n_am-fm_receiver_sch.pdf/download.html (thanks @rsjsouza) and is also inside the radio (wedged under the chassis) (S).

I know that this site is not an old radio restoration site and there are many of them out there. I have spent the last few days reading through them and other places. Full on restoration seems to involve replacing all capacitors and more. The radio works and I would like to get it to the point where I could occasionally use it without fear of bricking it. I do not want to sell it.

I wonder if I could ask a few basic questions here.

1. Can I remove all the dust by careful use of a vacuum cleaner (held away from anything movable) and an artist's brush? Any better way?

2. Do you see evidence of prior repair e.g., (1A,1B) the drilled holes under the primary (or was that for heat dissipation?) 

3. Is the corrosion on a tuner knob mechanism (2A, 2B) and the fuse (6A) and an output jack (6B) a huge problem and a must fix?

4. I know that the underside of the chassis contains point-to-point soldered components (4A). I have looked without seeing any huge red flags, but realize I will need to inspect them carefully. I am just not read to remove the chassis...yet.

Funny, I had recently called a moratorium on new projects until I finish a ton of current projects - but what was I to do - this walked in the door!

Thanks for any help/advice you can give.

TimFox:
To start with, I would try to remove as much dust as possible with a vacuum cleaner and brush attachment, to minimize blowing dust around into other places.  Then, an artist brush would be good to go after the remainder between tubes, etc. that you couldn't reach.  Is the dust oily or dry?
The corrosion on the frame of the tuning capacitor:  I assume the metal here is aluminum, and the corrosion from damp storage.  I would think it would come off with a cloth, but again you want to avoid getting junk into other nooks and crannies. 
More worrisome would be corrosion on the semi-circular plates that form the actual capacitor, but they look OK from your photo.

DrG:

--- Quote from: TimFox on July 24, 2021, 08:48:57 pm ---To start with, I would try to remove as much dust as possible with a vacuum cleaner and brush attachment, to minimize blowing dust around into other places.  Then, an artist brush would be good to go after the remainder between tubes, etc. that you couldn't reach.  Is the dust oily or dry?
The corrosion on the frame of the tuning capacitor:  I assume the metal here is aluminum, and the corrosion from damp storage.  I would think it would come off with a cloth, but again you want to avoid getting junk into other nooks and crannies. 
More worrisome would be corrosion on the semi-circular plates that form the actual capacitor, but they look OK from your photo.

--- End quote ---

The dust is basically dry, but it is caked on there and I have yet to make any attempt at removal.

That corrosion *looks* like it is on the frame and not on the wheels. It tunes fine on FM and AM, to the degree that it was tested. In fact afaik all the functions appear to be working well - again, I did not want the unit to be on for more than a minute or so.

TimFox:
Do you have a smallish vacuum cleaner available?  Perhaps if you get the long-handled (medical-type) Q-tip cotton swabs, you can dislodge the caked-on dust into the vacuum-cleaner nozzle.  Of course, you are trying to avoid scratching the surfaces, as well as not shoving the dust into crevices.

richnormand:
After cleaning as described in the above posts I would take a close look at what appears to be a scratch on the transformer photo.
If superficial or cosmetic all is good. If it goes down to the copper winding it needs attention as you do not want a shorted coil.

Next I would check what appears to be a fuse with lots of corrosion on the contacts for continuity.
Finally a Variac to bring to voltave up slowly. If OK,  reform the capacitors while closely monitoring its behavior.

Moving/rocking the valves (tubes) in their sockets with power off and all controls should help too.

Then the troubleshooting and restoration starts if it did not come to live. You might be surprised on how these old units are rugged compared to the cheap stuff we have today.

Good luck with it.

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