Grundig 5050W - restoration (ENG)

[PJ.]

Hello
Recently I bought this model for quite a good price. As condition is not so good, I will try to report all my work, I hope it will be interesting also for you. It looks like it is top quality radio, certainly one of the most sophisticated I ever seen. Radio is complete with rear wall, which is signed "Otto Riemer, Bamberg".

Here's what it looked like:






At first glance:
- there's no lacquer finish at the top of the housing.
- small part of brass line is cut on the left side
- brass insert from knob is missing
- Philips trafo instead of Grundig's.
- chassis and loudspeakers with no rust.

But, on closer inspection I found, there are some cores missing from ZF filters
Two of them are missing and two are broken. What are the chances of getting such cores?

Nevertheless I will restore it completely with new coat of finish and thorough cleaning and I hope to share more pictures soon.

Best regards
Piotr

[radio-hobby.de]

hello Pjotr,
wish you good luck.
Please show Makro-Photos of the core you miss. If possible do the foto together with a millimeter-scale.

geetings,
Georg N.

[PJ.]

Hello
I enclose picture of these cores. diameter of the core is ca. 4mm and this plastic casing ca. 6mm.
In service manual AM cores are described as Stabkern-Ferrit (part nr 807-006) and FM cores as Stabkern (807-009), although they look the same.



I dismantled a radio for cleaning, and another bad surprise - one of the hochton loudspeakers is broken, apparently tension of the spring pushed through this thin foil. The other one seems to be OK. Should I try to repair it or switch to different loudspeakers?



Chassis has undergone usual treatment - warm shower, of course without transformers. Then I dried it with a hairdryer and put it in the sun. Although this gray dirt on the right side of the chassis doesn't want to come off, chassis is again good to work on.



Now it's time to clean contact switches, potentiometers and tuning system.
I'm going to paint front panel, as old layer has flaked off in several places.

Regards
Piotr

PS Could moderator move this topic to "Reparatur & Technik"?

[hoeberlin]

Hi, Piotr,

about the IF cores. If they have different Part Numbers, then they are different ( even if they look the same ). The Response of the Core on higher Frequencies ( 455kHz / 10,7MHz ) will be different.

I think, that Grundig has used these cores in many Radios, so it schould be worth looking for the same Part Number in manuals of different Models.

If my Idea is right, the it schould be easier to find such Cores.

Best Regards,

Henning

[PJ.]

Hello,
what kind of loudspeaker are you suggesting to replace this broken electrostatic?
Currently I'm slowly painting housing.

PJ

[Ralph]

Hello PJ,

how to repair/restore an electrostatic tweeter from a Grundig 5050 please follow the link:

http://www.radiomuseum.org/forum/electr ... ation.html

With best regards,

Ralph

[PJ.]

Hello,
I repaired electrostatic tweeters like that, but this one is of different type - see my picture above. Seems like it's irreparable.

Regards,
PJ

[PJ.]

Hello,
I started preparing for tuning. I replaced missing cores with different ones from another radio.
I have a question, what does "außere Maximum" means in the sentence "Alle Kerne aus das außere Maximum abstimmen."?

Piotr