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American Bosch Model 48 restoration

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American Bosch Model 48 restoration Empty American Bosch Model 48 restoration

Post by jswebb82 on Wed Nov 21, 2018 3:38 am

So, I have been tasked with the restoration of an American Bosch Model 48. I visually scanned the internals for any blazingly obvious no-no's, I didn't see anything out of the ordinary (melted, burned, etc.).

I plugged in the radio, and it hummed to life, and one tube started warming up. My excitement was cut short by what I can only assume to be a capacitor of some sort (having trouble finding schematics online) starting to smoke a little bit, with a burnt plastic smell emitting from the box where that particular part is located. So, I took the cover off of that part area, and there are a few different components inside of it, one looks like some sort of wound wire around a box, with layers of some sort of plastic tape in between each layer. This is the part that was smoking.

So, a few questions:

1. What is this particular component?

2. Is there a replacement for said part, and does someone know where I can find a good replacement?

3. If no replacement, is there a way to rebuild this particular part, and have it work for another 50 years without damage to the rest of the radio itself?

Keep in mind, I am new at this and have just been tasked because I am mechanically inclined to an extent. Please don't be too harsh. Razz


(EDIT: I believe this part to be the transformer. I don't know much about resistances and ohms. Can someone please educate me on what the heck I am looking at? hah)

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American Bosch Model 48 restoration Empty Re: American Bosch Model 48 restoration

Post by Bill Cahill on Wed Nov 21, 2018 7:03 pm

jswebb82 wrote:So, I have been tasked with the restoration of an American Bosch Model 48. I visually scanned the internals for any blazingly obvious no-no's, I didn't see anything out of the ordinary (melted, burned, etc.).

I plugged in the radio, and it hummed to life, and one tube started warming up. My excitement was cut short by what I can only assume to be a capacitor of some sort (having trouble finding schematics online) starting to smoke a little bit, with a burnt plastic smell emitting from the box where that particular part is located. So, I took the cover off of that part area, and there are a few different components inside of it, one looks like some sort of wound wire around a box, with layers of some sort of plastic tape in between each layer. This is the part that was smoking.

So, a few questions:

1. What is this particular component?

2. Is there a replacement for said part, and does someone know where I can find a good replacement?

3. If no replacement, is there a way to rebuild this particular part, and have it work for another 50 years without damage to the rest of the radio itself?

Keep in mind, I am new at this and have just been tasked because I am mechanically inclined to an extent. Please don't be too harsh. Razz


(EDIT: I believe this part to be the transformer. I don't know much about resistances and ohms. Can someone please educate me on what the heck I am looking at? hah)

We need to see pictures, but, I wish you hadn't plugged it in. I suspect hat you have fried the power transformer. Parts for these sets are very hard to get. You might be able to get the transformer re wound, but it will be expensive.

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American Bosch Model 48 restoration Empty Re: American Bosch Model 48 restoration

Post by jswebb82 on Thu Nov 22, 2018 1:50 am

It had already been plugged in by the owner previously. I just needed to see what it was doing. It was plugged in for maybe 10 seconds total. I will take pics when I can and throw them in this thread. I just need to know what y best route is from here. Also, maybe is there way to use an updated transformer in it's place instead?

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American Bosch Model 48 restoration Empty Re: American Bosch Model 48 restoration

Post by Tony V on Thu Nov 22, 2018 1:58 am

Yes, you can use an updated transformer once you find out the spec's of the old one. If you look in the different sections of the forum, at the top of the page there is a tutorial on how to post pictures on your post's here. If you have any difficulty just let us know and we will guide you through it.
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Post by Tony V on Thu Nov 22, 2018 2:11 am

You have probably already found this but i thought i would share it anyway. It's a couple of pages of the wiring diagram for it. It also mentioned the set was built in 1929.  

American Bosch Model 48 restoration Americ10

American Bosch Model 48 restoration Americ11
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Post by jswebb82 on Thu Nov 22, 2018 11:35 am

Tony V wrote:You have probably already found this but i thought i would share it anyway. It's a couple of pages of the wiring diagram for it. It also mentioned the set was built in 1929.  

American Bosch Model 48 restoration Americ10

American Bosch Model 48 restoration Americ11

Yes, I already found that one, but I'm not sure how to decipher it. That's about the only thing on the net schematic-wise.

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