Grebe Synchrophase Seven

3/7/2016

This is probably going to be the last restoration prior to the large project mentioned below.

GREBE SYNCHROPHASE SEVEN
Using five 201As a 112A as a first audio and a 171 running at 180 volts, this is one of the LOUDEST battery radios that I have restored. It is also one of the least likely to be seen in operation due to the extensive use of pot-metal parts.

The inlayed brass escutcheon is worth having even if the rest of the radio is gone. This is another part that is often damaged.

In the spirit of the MU-1, the Seven drives the tuning caps in sync, eliminating 2 of the tuning knobs but adding 2 more stages for a total of 5. That is a lot of mass being driven by one knob.

And this is what the linkage looks like after it crumbles into small chunks. The pot metal has degraded to the strength of dried mud. It can easily be crumbled with your fingers.

Above is a "reject" replacement part made of steel. Since the six linkage parts (5 on the caps and one pivot) must be the same length to have any hope of working, this one failed buy about a 1/16 of an inch. Keep in mind that the fine tuning turns a metal roller against the Bakelite main tuning knob - not much friction - so even more need to be accurate.

Toner was custom mixed and applied with an airbrush.

It will take a few days to dry enough for reassembly. I'll add a finished picture then.

27 Comments

Phil Kordish

5/5/2019 08:38:46 pm

Where does the tuning knob attach to the linkage ? I don't see any pot metal damage and both tuning dial turn but no movement on the linkage. Phil

Russ

5/7/2019 09:10:43 am

There is a vertical shaft that ties the coarse tuning control to the linkage and another connection to the fine tuning control but it is through a clutch which may slip if the assembly is warped, cracked or broken as is often the case, as found.

Geneva

7/22/2020 12:55:31 pm

I was living in Tenino Wa back in 1996, when I was salvaging with a friend of mine, and I came across a face plate, and its for the radio you refurbished. I was going thru stuff I hadn't looked at since we moved to NC 15 yrs ago. Well we are going back to Florida, so I'm going thru stuff, I came across the face plate and looked it up and came upon your page. You have done a beautiful job, and radio is gorgeous, now if I can only dig up the rest of the pieces to have a whole one....

Russ

7/22/2020 01:04:13 pm

Thank you and good luck finding the rest of your radio.

Geneva

7/22/2020 01:11:31 pm

Ive been looking online at other radios, and they have wooden face plates, mine is brass, can you tell me which ones have the brass face plate.

Russ

7/22/2020 01:20:10 pm

If you have the brass/wood front panel like the one at the top of the post, then only the Syncophase 7. Keep in mind that because of the pot-metal issues, few of these radios will ever work again.

Glenn Greenough

10/10/2020 09:13:34 am

I have recently come across two of these radios while helping an old collector move out of his house. I am looking for a good home for them as restoring one is beyond my skills. One looks beautiful with a so so case, and the other looks dusty with a case in good shape. One is the battery model and one is the AC model, though I don't see much difference looking at the chassis. I can send you some pictures if you are interested. Glenn

Tony Hirn

9/11/2021 02:35:17 pm

I just bought the same radio at a rummage sale. Where is a good source of replacement tubes for the Grebe syncrophase radio?

Phil Kordish

10/11/2020 12:23:16 pm

I'm looking for a front panel for my Grebe battery set. Phil

Glenn

10/14/2020 10:16:12 am

I have the box from one of these radios with the face plate that someone turned into a really big jewelry case with a red velvet interior. The knobs from a radio were attached for appearance. The face plate is in good shape but I don't know how to remove it without damage. The person who built the box cut the tuning knobs so they can attach flat to a piece of wood behind the plate. The plate seems to be wood and brass (battery version of the radio.)
I also have two radios. One is the chassis only (maybe it came from the box mentioned above) of an AC radio (no power supply.) This shows it's age but is all there except the tubes. The other one is a DC radio in the box with a clean chassis that looks to be in good shape. The box needs some TLC and refinishing. The guy I got them from probably has the tubes, but he is moving and can't search for them right now. Is there a way I can post pictures to this site? The radios are free to a good home.

Ron McCulley

2/16/2021 04:35:34 pm

I would love to get some detailed close up pictures and dimensions of the wooden feet. Mine were missing
Second I would like to get a square on picture of the front bezel mine needs work so I’m looking at options to copy it to scale if I can get some multiple pictures. Close up of each area and a complete bezel picture squared off for a duplication attempt

Thank you

Russ

2/17/2021 07:52:37 am

The original bezel is made from a brass plate from which the text and decoration is raised. The wood panel is inset allowing the brass design to come through. A person might be able to engrave a brass plate with a CNC/CAD. This would be the most difficult escutcheon to duplicate, that I can think of.

Glenn Greenough

2/17/2021 12:47:55 pm

I can give you pictures of the panel and feet with dimentions. I just don't know how to attach them to this post.

Russ

2/18/2021 06:47:59 am

Glenn,

If you send me your email address I can forward it to Ron. I think I have an email from him (prior contact). Use the contact form.

Russ

Glenn R Greenough

2/18/2021 06:56:53 am

Sure, Russ, here it is
[email protected]

WA2FXM link

8/7/2021 04:05:59 pm

Russ, I've got the same bad pot metal problem. You mention your "reject" steel replacement piece. Did you finally successfully rebuild the rig with good steel pieces? Is that something to look into for someone like me who has no experience with metal fabrication?

Russ

8/7/2021 04:16:29 pm

Yes, the radio tuning is fully functional. I got better at making those parts. The only reason that I posted a picture of the "reject" is that the others (good ones) were already installed by the time I thought of taking a picture.

So yes it can be done. Finding a piece of U-channel to cut the parts from would be a big help. The one I used just cam from the "Junk Metal" bin in the woodshed.

Basically you need to copy the form and function of the originals - less cracks and potmetal. You are going to have to thread that grub-screw hole.

Russ

WA2FXM

10/21/2021 10:16:09 am

Hi again Russ,

I found a casting company that made brass linkage replacements. They work great and I've got the Grebe functional. Now on to the cabinet and the brass\wood bezel. On my bezel it looks like there's a lacquer? layer over the wood. On the bottom the wood has raised up from the plate and I can flex it with my finger pressure. Pictures here ( https://cvths.org/radio/stuff/ ). Any advice on getting this one to look as good as yours? Thanks.

Mark - WA2FXM

William Bruce Thompson

3/11/2023 04:48:45 pm

would like more information on the brass linkage replacements parts
William

Mark Mohrmann link

3/17/2023 04:59:27 am

Ace Castings in Colchester Vermont. Had no idea they existed, just did a local search for metal casting establishments. They made the mold and 7 pieces for about $150. Details at the above url. The owner Phil just happens to collect old AM portable radios and Edison phonographs.

Mark Mohrmann link

3/17/2023 05:01:09 am

https://cvths.org/radio/1920s/grebe.html

Russ

3/17/2023 01:31:40 pm

Thank you very much. I wish I had known that prior to my rebuild. I wonder if he can make any of the other potmetal parts, like on the tuning caps?

Mark Mohrmann link

3/17/2023 02:06:26 pm

He told me in our email exchanges that he does sometimes make parts for his radio and edison collection.

John J Fritz

4/14/2024 07:02:49 am

Great work and a beautiful cabinet! I've had one for many years and just got around to working on it. Yes, it has pot metal issues, but not real serious. Many years ago (probably in the 30's, based on the parts) someone added capacitors since a few of the original 2mf ones must have become leaky. Do you or anyone have some pictures of the underside of the chassis? I saw the one on the CVTHS site, but several of the Caps and resistors are not there?! Mine is the AC version, that is to have the separate power supply unit, which I don't have. The Rider's schematic seems to be fairly accurate, but some of the resistors were also replaced previously and are now open also. Some of these are HUGE, maybe >= 20W? Seems a bit over sized. The Audio transformers are good which was a relief! The AC version should have two 1mf and three 2mf caps, which are in black rectangular cans.

Russ

4/14/2024 07:54:39 am

John,

The picture of the underside has been added to the OP.

I have not seen an AC version but it is probably way more complicated then the battery version.

Russ

John J Fritz

4/14/2024 09:10:34 am

Thanks Russ!
Yes, a few more parts on the AC version. I attached mine, in it's current state. You can see more cap's and resistors. The parts you had reproduced on yours appear to be brass on mine. But it is missing the part at the top on the pivot arm. It was pot metal. There should be a 3rd 2mf black can that is missing. The Sprague cans were added early in it's life to replace the missing one, and across one of the existing. I'm thinking the "white" wirewound resistors may be original, but the other large brown ones (3) appear to be replacements.I don't have a spare 2mf size can in the junk box, maybe I can find one at the Spring Renninger's meet in May. These are easily re-stuffed, as you know.

John J Fritz

4/14/2024 09:13:39 am

Hmmm. How do I attach a jpg to this thread? Sorry!

Grebe Synchrophase Seven

Leave a Reply.

Author

Categories

Archives