grundig: 5490 Stereo/U; Konzertgerät ;Flat wishbone Device
grundig: 5490 Stereo/U; Konzertgerät ;Flat wishbone Device
Is anybody familiar with the flat wishbone element that is attached to the off switch and FM(UKW) switch?
How does one fashion a replacement, and what does it exactly do?
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Wishbone/Schaltgabel
maybe that Hr. Knoll is able to give you the desired information, but you should take into account that in general most radiomuseum people are not Grundig and keyboard experts respectively. Therefore we need at least a photo or a figure from this device.
Best regards
Rolf
P. S. : Is it a part similar like this (Grundig 5570, power on/off - switch operation lever, see white arrow) ?
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Hi Rolf,
Thanks for the reply!
The device is a little different, but I will prepare some pictures later today and post them to the forum.
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From the schematic, it is the line that connects the OFF switch to the FM(UKW) switch with a dot in the middle. It is about 40 cm long, made out of die cast metal, that has disintegrated.
Attachments:- Grundig_5490_rockerarm (127 KB)
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Where is the original part ?
the provided illustration helps to understand the principle but not to solve the problem. I think you need a spare part - the 40 cm lever.
If so, then I would propose again to draw a figure with dimensions and additionally to make a photo of the damaged or broken part (you did not throw it away, or did you ?!). It should be no problem for a craftsman to build such a lever for you, but why do you not try this yourself ?
Best regards
Rolf
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I believe that Omer may be referring to the "cross-shaft" which, if it is broken, will effectively disable the AM bands and the FM bands. The term cross-shaft is the term that I have been using for more than 10 years.
The Bavarian radio specialist, Mr Ross Hochstrasser, described the part to me years ago after I had purchased my 2nd model 5490StU receiver. It is as Omer stated that the item was made of the "cast white metal (zinc type)" - it was also called Pot metal . . . . .
The repair procedure is quite extensive - much dismantling is required to repair the malfunction; and there was a better type of shaft available.
Consequently, I have 2 models 5490StU with the broken (separated) shafts. I understand from Mr Hochstrasser the best "repair" is to use the better quality cross-shafts from either one of the 2 largest Konzertschranks - in the last years of the 8 and 9-series models. According to him, the shafts were made of a different material.
Respectfully,
Robert
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Gentlemen, here are the pictures of where this device goes to on the 5490, and its remnants.
If I could get pictures and measurements of the device, I could have one machined, and then have more machined for RMorg members.
It would be good to know which of the Grundig models use this apparatus as well, since it looks like this is the main reason these radios get junked!
BTW How come Ross doesn't join RMorg?
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- IMG_0919 (25 KB)
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It was machined from a flat peice of aluminnum barstock with rolled pins in the ends.
Jeff
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If Dennis is following this thread, maybe he has some insight and information on making and installing the cross-shaft back in to the radio.
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I have just received email from Ross Hochstrasser of Bavarian Radio in Massachusetts, that he has bronze replicas available for this model as well for others.
He can be contacted at, bavarianradio@comcast.net.
From my understanding, he has extensive experience repairing these radios and is considered the dean of European radios in the East Coast!
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Grundig 5490 FM switch lever
Hi All,
This is my first post to this forum Thank you for your patience. Sorry it took so long!
I have had some bronze castings made from an original lever removed from an 8050 console chassis. There seems to be a difference in the composition of the alloys between 1958 and the mid 60's as the earlier ones I have found seem perfectly intact and the ones in the 5490's are mostly disintegrated. Unfortunately, the bronze ones are slightly thicker and require some minor machining (which I do here) in order to make them work properly. The originals were die cast, which is a more precise method than sand casting which is what I had done. I have had conversations with other radio enthusiasts here in the U.S. who have substituted 4 pole double throw relays in place of the lever and associated slide switch, which works OK but you have a continuously energized coil when the radio is operated in the MW or KW positions. The procedure for replacing this lever is lengthy and tedious, but worth the effort. Good Luck!! Ross Hochstrasser
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Welcome aboard. . . . .several members have inquired about your presence (or non-presence) in the past.
I am glad you have stated that the "cross-shaft repair" is not a simple task; and there appears to be a distinct difference in the composition of the shafts!
Respectfully,
Robert
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It's about time Ross!
Welcome to RMorg, your presence and participation will be invaluable to all of us, here on this forum!
As for everone else, don't junk those Grundigs!
Ross has a mechanical solution for everything on these and many other radios.
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Out of curiousity, what are the other Grundig models that use this particular cross-shaft?
When did Grundig start using pot metal and why, when other materials are better?
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Grundig 5490 Cross Shaft Design
I have one of these that works, but with some problems with the cross shaft of course.
This design, especially with the 'pot metal' shaft does not seem to be consistent with the most Grundig designs. I wonder if this design was done be one of the companies Grundig purchased?
Was this unit designed and manufactured by Grundig or by some other company?
tom
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I'll be making a production run of these shortly.
Jeff
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