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 Post subject: Playing with Raytheon 8TP prototype !
PostPosted: Aug Fri 21, 2020 9:08 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
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Location: Indianapolis, IN
Hello All,

An old friend of mine who now lives in SC was in area and stopped by to pick up a Realistic QTA-770 Quad receiver that he had recently bought from me. Asked me before he came if I wanted to take pictures of his Raytheon 8TP plexiglass-cased prototype that he'd bought many years ago for his collection and of course I did, so he brought it with him...

The Raytheon 8TP was the 2nd production superhet all-transistor radio in the world from 1955...

Hadn't seen it in person for around twenty years and was excited to be able to examine it closely after returning to the "hobby".

Took several hi-res pics which I'll gladly share with anyone interested---resized images below in two "installments"...

Bret actually let me pull cover for the first time since he's owned it and I installed batteries to see if it would work. Unfortunately, just a slight audio "hiss" and no reception. Tuned back and forth for several minutes at maximum volume just in case the caps might "reform" enough to hear a strong local, but no luck... Didn't even ask if I could use clip-leads to jumper the audio coupling cap with good part as I considered myself fortunate just to be able to open it up !

What a privilege to be able to "play" a bit with this one-of-a-kind, historic radio and to take pictures of it along with the 8TP-2 & 8TP-4 from my collection !

John


Attachments:
1ARF RAY PROTO BOT 8-21-20.jpg
1ARF RAY PROTO BOT 8-21-20.jpg [ 279.51 KiB | Viewed 609 times ]
2ARF RAY PROTO BOT-FRT 8-21-20.jpg
2ARF RAY PROTO BOT-FRT 8-21-20.jpg [ 339.9 KiB | Viewed 609 times ]
3ARF RAY PROTO BOT-BK 8-21-20.jpg
3ARF RAY PROTO BOT-BK 8-21-20.jpg [ 335.72 KiB | Viewed 609 times ]
4ARF RAY PROTO RT 8-21-20.jpg
4ARF RAY PROTO RT 8-21-20.jpg [ 334.56 KiB | Viewed 609 times ]
5ARF RAY PROTO LFT-TP 8-21-20.jpg
5ARF RAY PROTO LFT-TP 8-21-20.jpg [ 308.21 KiB | Viewed 609 times ]
6ARF RAY PROTO TOP 8-21-20.jpg
6ARF RAY PROTO TOP 8-21-20.jpg [ 315.59 KiB | Viewed 609 times ]
7ARF RAY PROTO FRT-TOP HNDL DWN 8-21-20.jpg
7ARF RAY PROTO FRT-TOP HNDL DWN 8-21-20.jpg [ 459.89 KiB | Viewed 609 times ]
8ARF RAY PROTO BK 8-21-20.jpg
8ARF RAY PROTO BK 8-21-20.jpg [ 568.64 KiB | Viewed 609 times ]
9ARF RAY PROTO FRT 8-21-20.jpg
9ARF RAY PROTO FRT 8-21-20.jpg [ 682.38 KiB | Viewed 609 times ]
10ARF RAY PROTO BK-TOP 8-21-20.jpg
10ARF RAY PROTO BK-TOP 8-21-20.jpg [ 420.31 KiB | Viewed 609 times ]


Last edited by xrhonda91 on Aug Fri 21, 2020 9:40 pm, edited 2 times in total.
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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Fri 21, 2020 9:09 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 6616
Location: Indianapolis, IN
Here are the remainder of pics---please see previous post for first group !

John


Attachments:
11ARF RAY PROTO FRT-TOP 8-21-20.jpg
11ARF RAY PROTO FRT-TOP 8-21-20.jpg [ 604.96 KiB | Viewed 608 times ]
12ARF RAY PROTO BATS IN 4-TST 8-21-20.jpg
12ARF RAY PROTO BATS IN 4-TST 8-21-20.jpg [ 541.32 KiB | Viewed 608 times ]
13ARF RAY 8TP-2 PROTO 8TP-4 BK 8-21-20.jpg
13ARF RAY 8TP-2 PROTO 8TP-4 BK 8-21-20.jpg [ 278.92 KiB | Viewed 608 times ]
14ARF RAY 8TP-2 PROTO 8TP-4 FRT 8-21-20.jpg
14ARF RAY 8TP-2 PROTO 8TP-4 FRT 8-21-20.jpg [ 271.26 KiB | Viewed 608 times ]
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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Fri 21, 2020 9:22 pm 
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WoW :shock: Awesome, I'm speechless.

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Fri 21, 2020 11:08 pm 
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John - Thanks for posting the photos of the Raytheon 8TP prototype! Interesting that all of the transistors are the "blue" type and not the CK-721 transistors, which are black. - Mark


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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Fri 21, 2020 11:15 pm 
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Talk about unique...Thx for the narrative and pictures, John!

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Fri 21, 2020 11:55 pm 
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Very nice !!! Thank you and your friend.

Al

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Sat 22, 2020 1:06 pm 
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Thank you for posting these pictures. It's nice to be able to examine the construction of the one-of-a-kind prototype.

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Sun 23, 2020 8:20 pm 
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Hi John,

There is one observation I'd like to make about this prototype. Please correct me if I'm wrong.

The date code on the speaker is 504, a week earlier than the one in this illustration showing an early (type 1) 8RT1 chassis.
Attachment:
Raytheon_8TP_ch8RT1_early.jpg
Raytheon_8TP_ch8RT1_early.jpg [ 110.77 KiB | Viewed 456 times ]

Note that the cutout for the speaker has a round top edge; the magnet structure is secured with two screws to a tab on the left edge of the cutout; the magnet structure is butted against the audio output transformer.

The prototype chassis has a speaker cutout with a straight top edge; the magnet structure is indirectly secured to the left tab by an L-bracket; the speaker is mounted higher (gap between magnet and transformer is wider) and a little bit further away from the chassis towards the front. This is consistent with the late (type 2) 8RT1 chassis and later (type 3) 7RT1 chassis (used in both of your 8TP-2 and 8Tp-4). This led me to believe that this is not a first engineering prototype but a revision prototype to show the effect of mounting the speaker differently.

To prove all of this, I have pictures of an 8TP-1 with an early 8RT1 chassis that showed up for sale in May of 2019. The speaker date code is 505, same as the one in the illustration. Again, pay attention to the shape of the speaker cutout in the chassis and how the speaker is mounted relative the audio output transformer. (I didn't followed to see whether it was actually sold or not since it had an opening bid of $495.)
Attachment:
Raytheon_8TP-1_ch8RT1_early_207b.jpg
Raytheon_8TP-1_ch8RT1_early_207b.jpg [ 603.54 KiB | Viewed 456 times ]

Attachment:
Raytheon_8TP-1_ch8RT1_early_210b.jpg
Raytheon_8TP-1_ch8RT1_early_210b.jpg [ 651.31 KiB | Viewed 456 times ]

Attachment:
Raytheon_8TP-1_ch8RT1_early_211b.jpg
Raytheon_8TP-1_ch8RT1_early_211b.jpg [ 727.35 KiB | Viewed 456 times ]

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Mon 24, 2020 12:16 am 
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Location: Indianapolis, IN
Thanks for the info, Binh---will let Bret know this and send him a link to this thread. He isn't often on the computer and is still traveling until early next week.

Went through my 8TP folders and discovered that Bob McGarrah noticed the same thing and considered this a "demonstration model"... Bret said that there was a newspaper article and picture, but can't find it...

Guess I should have done my research before getting so excited !

John


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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Tue 25, 2020 9:26 pm 
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The design of this radio was disclosed by Raytheon in an article published in the March 1955 issue of Electronics, pp. 159-161. Shown there are three pictures of the actual engineering model which doesn't resemble the production chassis at all.
https://worldradiohistory.com/Archive-Electronics/50s/Electronics-1955-03.pdf

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Tue 25, 2020 11:37 pm 
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Location: Indianapolis, IN
Thanks for link, Binh---saved it to folder !

I'd already added pics of that experimental set from a different source, but appreciate having that article also...

Am wondering if Raytheon made display samples for each of their 8TP designs and this was just one of them ?

May never know...

John


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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Wed 26, 2020 12:00 am 
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Had one of those once that I picked up for 10$? but never got it working right. Cosmetically excellent so someone bought it as-is just because of what it was.

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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Aug Wed 26, 2020 12:09 am 
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Location: Palos Verdes, CA
Interesting article on the Raytheon laboratory model, which starts on page 159, which wasn't the design used for the production Raytheon 8TP. While the 8TP eventually ended up with 7 transistors, I think that the one that John took photos of could have been used for demonstrations as it has the newer Raytheon blue transistors, which work considerably better than the black CK-721 transistors that were used in hearing aids. I have one Raytheon 8TP which uses 4 CK-721 transistors and it doesn't perform as well as the 8TP that uses the blue CK-722 transistors. As Raytheon was only briefly in the commercial transistor radio business, I doubt that they would have built demonstrators for the different versions of the 8TP transistor radio. Thanks for all the postings as Raytheon transistor radios are one of my favorite manufacturers to collect! - Mark


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 Post subject: Re: Playing with Raytheon 8TP prototype !
PostPosted: Sep Wed 02, 2020 2:44 am 
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Thanks for posting the photos of this piece of radio history.


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