Blaupunkt Riviera 2643 - no sound!

[thisismyyear]

Hello to all!

I recently picked up the above table radio off eBay. 1960 vintage I believe. As beautiful as it is, unfortunately it came to me in less-beautiful condition. The case is cracked in 2 corners and there is no sound. I replaced the main fuse and I get dial lights and some glowing tubes but no sound/static at all on any function...even from an iPod through the aux input. Only the faintest hum when you put your ear right up to the full-range speaker. There do not appear to be any obviously-broken leads or connections....except for one thin wire on the ferrite bar. A tube radio repairman suggested I am not getting B+ voltage to the tubes and that I should check the power resistors in the power supply. Unfortunately I do not know how to identlfy/test them. I also understand this can be dangerous. The radio has not been powered on in weeks though.

Any suggestions on how to get some life out of this beautiful radio would be appreciated! The seller refunded all my money so all I have in it is $2 for the fuse!

Thanks
Steve

[Celt]

More than likely, the electrolytic capacitors have dried up making them useless.
If you aren't familiar around electronics, find someone competent to replace them for you and also have them check the resistors.

[Electronic M]

A schematic will help in parts identification. You need a model number to find the schematic, and schematics can be hard to get for euro imports like your set.

One test you can do is with the set on try wiggling or removing the audio output tube. If you hear pops/crackling from the speaker then B+ voltage is present at least at the output tubes.

Some euro sets are not worth restoring. They used lousy band switches that would break easily, and some would dissolve if the wrong type of control cleaner was used on them. If the band switch wafers are broken then it is limited to parts set or display piece status since the only source of those switches is another set with the same chassis.

[thisismyyear]

Good points, gentlemen. Since the set was sent out as "working" I would hope all the components functioned at least well enough to produce sound when it was shipped a few weeks ago. As to wiggling the output tube, would have to figure out which one it is...I did carefully remove and replace all the tubes (using gloves so as not to create hot spots). Also, the power cord is attached to the back panel so I can't wiggle any tubes under power.

Would also have to locate the band switch wafers. Would I have to remove the chassis from the case to do so?

I am sure this is a low-value radio so wouldn't want to put a ton into it to fix it. Any suggestions on a reasonably-priced repair professional? I am in New York.

Anyone interested in it for parts?

[Electronic M]

The speaker is connected to the audio output transformer that is connected to the audio output tube (and B+) you just have to trace it back.

Tubes, while not infallible, rarely fail in radio and audio applications (I'd be more suspicious of capacitors both filter and coupling types). You don't need gloves to handle tubes (unless you are removing them immediately after the set has been on for a good while)....Dust and finger prints don't hurt them, and as long as you don't wipe off the labels (which makes repairs less easy), or break the glass there is little you can do to damage them.

As for the cord being part of the back (called the safety interlock) you can get a separate appliance line cord that will mate with the chassis socket at ACE hardware (and possibly other places) for a few bucks.

Some euro sets put B+ and other unpleasant voltages above chassis so observe safety precautions while working with it powered and the back off. Keep one hand in your pocket, don't work on concrete, tile floor, or bare ground or with any part of your body touching an electrical ground.

Most euro sets have a sort of piano key bank of push buttons for a band switch that selects AM, FM, usually one or more SW (short wave) bands, and sometimes LW, and audio inputs.
Some are above chassis some are below. I've probably never worked on the exact model you have so I can't tell you much of anything about physical layout without a picture of the chassis.

If your set has an audio input connecting an audio source to it such as a MP3 player may give you some insight (if you hear clear audio then the audio stages are good).

[old_coot88]

A tube dropped on a hard floor can damage it internally even if the glass doesn't break. The internal structure is very delicate, especially in multielement tubes.

[fsjonsey]

Along with the filter caps that were mentioned earlier, a lot of these German sets had a full wave selenium rectifier in a black metal can that almost always goes bad. It almost looks like a slender upright electrolytic can cap, is black, and is usually marked AEG. Replace it with a modern bridge rectifier and a dropping resistor and you should be good to go! Don't forget the filter caps either. The rectifier and the filter caps are often weak points on these sets, and if they're toast, you'll get no B+.

EDIT: Apparently the rectifier on your set looks like this: