Grigsby-Grunow Majestic Model 50.

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Grigsby-Grunow Majestic Model 50.

Post by NashvilleRad on Sat Oct 13, 2012 9:04 am

Ran across a Grigsby-Grunow Majestic Model 50 with the optional table attached in a salvage/junk/antiqute shop (along with a stack of old Crossleys and other misc brand tabletop tube radios) , and was wondering if anyone had any experience working on one of these models ... tubes easy to get if needed ... etc.

I'll get some pictures later today.

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Re: Grigsby-Grunow Majestic Model 50.

Post by willy3486 on Sat Oct 13, 2012 7:38 pm

I had a Grigsby- Grunow that had a telephone dial like tuner.I don't remember the model. I had the front piece of the dial missing but I could tune it. It was one of the best I had but like a dummy I let it get gone. I couldn't find the parts and this was pre internet days. If I find another one like it and have the cash it will be mine. If the 50 is as good as the on I had it should be a good one.

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Re: Grigsby-Grunow Majestic Model 50.

Post by Bill Cahill on Tue Feb 12, 2013 10:03 am

My problem with the early Majestics is that most of the ac sets use a nasty power supply. Two power transformers that are wired for 90 volts ac input. They have this nasty toaster resistor in series with primary. Well, everything is encased in tar.
And, if a filter shorts, two things. It's instant horrible deat for the transformer, and, the resistor, which sparks, and, throws flames, and, if you catch it in time, doubtful, all filters, and, filter chokes are incase in tar in that power supply. Add heavey rubber wiring that goes bad to that, and, you have yourself one major nightmare to work on.

The best One I've found is the model 90. Nasty to work on, but, it uses a 110 volt transformer, so, no resistor. But, watch those voltages. Very nasty stuff, and, the no. 50 audio output tubes, rare, and, expensive.
The models most prone are models 70, 75, and, I think 50.

Bill Cahill

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Majestic 50

Post by mr_ed01 on Tue Feb 12, 2013 1:04 pm

Model 50 schematic indicates it is a superhet with a specified line voltage of 110V, no ballast resistor in series with the transformer. Uses push-pull 45 output tubes, somewhat pricey. Rest of the tubes are 24A and 27, fairly easy to get.

Also Grunow Teledial is a product of General Household, Majestic is Grigsby Gruno

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Restoring Grigsby-Grunow Majestic Model 50

Post by dan88king on Sat Oct 19, 2013 4:18 am

I had one of these when I was a kid. It had been damaged in a house fire, but only the cabinet wood back panel was charred. The family that owned it gave it to me, and it still played. I used to get 55 stations on it in the wintertime, with just a 30 foot wire antenna. I played it in the garage for several years, and then the transfomer started to smoke and the tar potting in the top of it bubble. It still played even then! I have one now right in my bedroom, that I bought in the early 1970's, but I never restored it electronically. It hasn't played for a long time. It is the spindly-legged curved top floor model cabinet.
This model uses a "filter block" with 3 MFD capacitors, and these are the ones that can short out and ruin the power transformer. I would replace them with 10 or 22 MFD, 450 volt rated electrolytics, observing polarity. You can get a schematic for the Majestic model 50 from www.nostalgiaair.org and print it out. The other capacitors and resistors are inside of steel enclosures with lids that have screws holding them on. I have seen some issues with rubber-coated insulation hardening up and wanting to fall off in chunks. I think it was in the speaker wiring. Like another post said, the eight tubes are easy to get except for the two 45 output tubes. I think it uses three 24A's two 27's, an 80, and the two 45's.
On the back of the chassis just to the right of the ANT and GND bakelite terminals is an antenna trimmer adjustment knob. It makes a huge difference in reception if it is correctly adjusted for the antenna you are using, after tuning in a weak station. It is very possible that the power supply in these old 1931 models can't take playing it on modern line voltage of up to about 122 or even 125 volts. The filter capacitors, I think, are wax paper and foil types, and always leaky. When I restore mine, I plan to operate it only on 110 volts AC, using either a Variac or a bucking transformer circuit to drop the line voltage. This also gives much better tube life, because their filament and heater voltages will be the normal 5 volts and 2.5 volts, not the higher voltages of about 5.6 and 2.8 if plugged directly into modern line voltage, which is about 12% higher than the radio was rated for in the early 1930's.
Even after replacing all the capacitors and any out-of-tolerance resistors (I replace them all to avoid future trouble), I bring these old radios power up slowly, using a Variac. This lets you check that the B-plus voltage is coming up normally and that the 80 tube plates don't start to glow red. Good luck!

Dan King

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Re: Grigsby-Grunow Majestic Model 50.

Post by Alan Douglas on Sat Oct 19, 2013 8:35 pm

The 50 was Majestic's first superhet, and they all came with the stand. I like the "skyscraper" look of the chassis but they are mechanically difficult to work on, and very heavy. 54 lbs as I recall, for a "midget" as they were called then. Majestic never did quite get the hang of making a cheap set.

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Re: Grigsby-Grunow Majestic Model 50.

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