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 Post subject: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 08, 2021 1:58 pm 
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I would love to get this working as I spend many hours at my Grandparents house in Brooklyn,as a kid, listening to it. My brother had this radio and said it was working about 6-7 years ago but a tube blew out. I recently bought new tubes for it hoping to repair it but it is beyond my skillset and it still needs a fuse to test it.(unknown type). If I find someone local to fix it, I would offer to buy it back and keep it for a few years. I would eventually sell it but I would like to hold on to it for awhile for the memories.
Was operational a few years ago and may now need a new tube/tubes and a fuse. All New tubes have been ordered and on the way. I just need a fuse to probably get it working.
Not sure what type/size fuse to get? Please help..
So far, I have replaced ECH81,EF89,EABC80 with brand new tubes and have ECC85 & EL84 on order.
Can not locate EM34/35 Socket Location. eBay item number:324894266366


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 08, 2021 3:41 pm 
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Location: Utica, NY 13502 (USA)
EM34 is the "magic eye" tube, upper-left, near the volume control.

Dave


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 08, 2021 4:03 pm 
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Joined: Dec Wed 08, 2021 1:46 pm
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I found it but thought it has a metal shield and broke it.
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I just purchased a used/working/tested one for $137.50.
I really need to know where to get a new fuse for this model?


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Thu 09, 2021 4:11 am 
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The schematic lists it as a 0.6A slow blow fuse for use on USA line voltage.

Take the existing fuse out of the radio and measure it. The two most common sizes are 5x20 mm and 6x30 mm... Hopefully it's one of those two. (If you can't identify it, post a picture here with the sizes you measure.)

Then you can search Amazon or Mouser or DigiKey for a replacement. It should be rated 125V or higher. Most common seems to be 250V-rated fuses these days. It might be easier to find if you search for a 600mA fuse instead of a 0.6A fuse. Also, slow blow fuses are often called Slo-Blo, an industry tradename. In other words it might be easier to find if you search for a 600mA Slo-Blo fuse instead of searching for a 0.6A slow blow fuse. But you'd probably find it either way.

Here's a typical listing:
https://www.mouser.com/ProductDetail/Li ... NvKg%3D%3D

Just make sure whatever you buy is the right physical size to fit into your fuse holder.

Another important question to answer is, why did the fuse blow in the first place? The purpose of a fuse is to protect equipment from short circuits, by cutting off power before a shorted component can damage other components. A blown fuse usually indicates some other part has failed. It's a symptom of a problem, not the cause. Simply putting a new fuse in without fixing the original problem is likely to result in nothing but another blown fuse.

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Measure it with a micrometer, mark it with chalk, cut it with a chainsaw.


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Thu 09, 2021 1:41 pm 
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I feel like an idiot damaging that expensive tube. I actually went to college for Electronic Technology in the '80's. I worked under a microscope tuning FET's on 2-4Ghz 20W RF Amplifiers that fit in the palm of your hand.
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Went as high as 18Ghz but never touched a vacuum tube before but I should of known better.
Anyone know what size & type of .7A fuse this Grundig uses?


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Thu 09, 2021 1:44 pm 
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Thank you for the fuse information. The fuse was jumped with a wire(no fuse) when I got it. Waiting for the rest of the tubes to come in before I try anything.


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Thu 09, 2021 1:54 pm 
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I believe this is the fuse holder. Any suggestions?


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Thu 09, 2021 1:59 pm 
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Joined: Dec Wed 08, 2021 1:46 pm
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and why are there wires on all three posts. Is it for 110V & 220V. What side would the fuse go on in the USA?


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Sat 11, 2021 4:32 pm 
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Location: Montreal (QC) Canada
lithomaniac wrote:
and why are there wires on all three posts. Is it for 110V & 220V. What side would the fuse go on in the USA?


Yes, as says your schematics ;-)

If in doubt, connect the mains cord to an ohm meter, ensure the set is switched in "on" position and measure, trying the fuse on both sides. The proper side for USA mains corresponds to the lower resistance.


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_________________
Experience is directly proportional to the amount of equipment ruined. (Harrisberger's 4th Law)
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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Tue 14, 2021 10:35 pm 
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The Grundig calls for a selenium rectifier B250 C75 N2. Is that a tube? I found a Philips Miniwatt GZ34 Tube 1958 PVM Code f31 X8G Sittard Holland in the box and I don't know if it belongs to this unit. If so, is it the rectifier and where does it go? Thank you very much for all your help, I really appreciate it.
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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Tue 14, 2021 11:27 pm 
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I now realize that a selenium rectifier B250 C75 N2 is not a tube but where is it located on this unit?


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 15, 2021 12:24 am 
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Joined: Jan Tue 31, 2012 1:55 am
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Location: Mountains of Mourne. Ireland.
Measure the distance between two of the metal fuse holders. It should be ~20mm

As mentioned, you require a 0.6A 5x20mm slow blow fuse.

Inspect the fuse holder for powdered corrosion + oxidation.

The fuse V rating is the maximum voltage, not the operating voltage.
T (time) marking on the barrel indicates slow blow, and F ...you guessed it, denotes Fast.

Any of the TIME DELAY fuses on this page will be okay.
https://cpc.farnell.com/c/test-equipmen ... 630ma-fuse
Manufacturers part numbers in the left-hand column. UK prices - - search Stateside.

630 milliamps equals 0.63 amp


Last edited by egg on Dec Wed 15, 2021 12:36 am, edited 1 time in total.

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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 15, 2021 12:33 am 
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Location: Mountains of Mourne. Ireland.
Typical rectifier found in German sets: Not your schematic.
Image


How to replace...

A replacement bridge rectifier along with a ceramic/cement "power" resistor can be seen halfway down this linked mbzponton page...
Selenium (semiconductor) Rectifier
German radios typically used...
viewtopic.php?p=2907620#p2907620


For Power Resistors (that get hot to touch and require heat dissipation) you can also use an Aluminum chassis mount type as seen here along with a couple of ceramic/cement types, (all wire wound).
Image

Greg.


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 15, 2021 1:49 am 
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Joined: Dec Wed 08, 2021 1:46 pm
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This is what I have on order for the fuse. NTE Electronics 74-6SC600MA Fuse-miniature 3ab Equivalent 6 X 30mm, Ceramic 600ma 125v/250V Slow Blow.
I hope it fits. Not looking to replace the rectifier just yet but I did find this rare odd radio tube eBay item number:324940736369.


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Wed 15, 2021 2:04 am 
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Joined: Dec Wed 08, 2021 1:46 pm
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Just in case, ordered Pack of 5, 5x20mm 750mA 125v/250v Slow Blow Ceramic Fuse


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 Post subject: Re: Grundig Majestic 7035 Vintage Tube Radio/Phono
PostPosted: Dec Tue 21, 2021 4:31 pm 
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Joined: Dec Wed 08, 2021 1:46 pm
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Thank you for all your help. I was about to give up on it, as it didn't turn on but decided to put it back together with the back cover. I gave it one more try and it was a Christmas Miracle, as I tuned into a local radio station to hear a Christmas Song playing. Now realizing that a tube or tubes may be light/photo sensitive. Working on the record player next and replacing the dry-rotted speakers.


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