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 Post subject: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Thu 09, 2017 12:40 pm 
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Joined: Nov Thu 09, 2017 11:29 am
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Just joining you all thanks to a suggestion by John of RadioBoatAnchor

Some years ago my son and I were given a Graymark 508 classroom project (see attached), and I've been sitting on it until now - that my 11 y.o. son is old enough to be interested.

Unpacking it, we discovered that it didn't include even a simple schematic. No problem, I thought ... surely we'll find something on the web. Testing my over-inflated sense of google-searching prowess, I haven't been able to find one - outside of an eBay'er selling a whole kit with unspecified documentation, and clearly stating in the ad that the literature would not be shared.

Looking at the board in the kit, it's pretty well labeled. Almost feels like we could figure it out - but that again is how my overconfidence and ignorance has treated me to frequent popped caps and smoked resistors.

So my questions to the community are:

"Any chance that idea could hold any water? Could that puzzle be solved without schematics?"

"Might anyone have a schematic that would be willing to share?"

Thanks in advance,

Luke

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File comment: Graymark 508 Transistor Radio Project
Graymark-508.jpg
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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Thu 09, 2017 3:57 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 11543
Location: S. Dartmouth MA 02748-1225 USA
http://www.graymarkint.com/

Contact for schematic. Inquired 15 ya cost was $10...


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 10, 2017 3:15 am 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 4974
Location: Indianapolis, IN
Welcome to ARF, Luke !

Are those component values on PCB or just numbers ?

Have you removed the cardboard backing of kit, yet ? Was wondering if schematic might be enclosed between layers of the thin cardboard...

It may use a common 2-transistor "boy's radio" circuit used in a "production" set---you could gather a few schematics online and compare to PCB trace layout and the supplied components...

Be patient as some members only occasionally "check in"...

And good luck !

John


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 10, 2017 4:14 am 
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Joined: May Wed 01, 2013 10:05 pm
Posts: 1375
Location: Rayleigh, BC, CANADA
Send me your email in a private message and I'll try to scan this for you.
I been working crazy long hours on snow plow equipment so it may take a day or two.

You're going to need 3 new electrolytic capacitors, the ones in the kit are guaranteed dead. This kit is from the mid 60's.
you can use 47uf for all 3 caps, even tho 2 of them are listed as 33uf


Attachments:
Graymark 508 Manual.JPG
Graymark 508 Manual.JPG [ 69.53 KiB | Viewed 543 times ]

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Rocco


Last edited by Rocco53 on Nov Fri 10, 2017 3:48 pm, edited 1 time in total.
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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 10, 2017 5:22 am 
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Joined: Sep Sat 29, 2012 6:32 pm
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Location: Endicott, NY
That's a nice looking kit, it should be a fun project once you have the instructions for it.


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 10, 2017 1:26 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
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Location: Indianapolis, IN
WOW---Rocco to the rescue !!!


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 10, 2017 4:29 pm 
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Joined: May Wed 01, 2013 10:05 pm
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Location: Rayleigh, BC, CANADA
John, the numbers on the circuit board are just reference points for the step by step assembly.

There were several kits offered to us when I was in high school back in the late 60's.

We started with the Graymark 502 Power Supply, then we moved on to the 508 Boy's

Radio, the 512 8-Transistor Radio and the 509-Tube Amp, I still have them all.


Attachments:
Graymark Kits.JPG
Graymark Kits.JPG [ 102.04 KiB | Viewed 501 times ]
Graymark 502 Kit.JPG
Graymark 502 Kit.JPG [ 85.11 KiB | Viewed 470 times ]

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Last edited by Rocco53 on Nov Fri 10, 2017 10:35 pm, edited 1 time in total.
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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 10, 2017 4:57 pm 
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Joined: Nov Thu 09, 2017 11:29 am
Posts: 4
Wow! (ノ・ェ・)ノ

Thanks for all the responses, and to John for introducing me.

Thank you so much, Rocco, for the offer!! I will contact you shortly.

We moved to Ireland a few months ago, so the time change thing has gotten in the way of timely correspondence with people in the states.

Hopefully, I'll have those caps in my drawers, if not, I'll have to begin to find where best to order components from over here.

We'll post updates, and look forward to more conversations with this community.

P.S. I'm a big fan of old-time radio and radio drama. When I was a kid, I listened a lot to CBS Radio Mystery Theater on the very radio in my avatar. Good old Archer Road Patrol that I took from my bike handlebars to bed with me at night. I love AM radio, and played around with box loop antennas when I was a kid to bring-in the distant stations.


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Sat 11, 2017 2:56 pm 
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Joined: Feb Sun 02, 2014 1:58 pm
Posts: 891
Location: Tennessee 38058
Welcome to ARF; I've had so much help from the knowledgeable people on this forum. You've just experienced that helpfulness.

Let us know how your kit turns out.

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Mike
KN4GGM

"This is the last radio I will ever buy, dear; I promise"


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Sat 11, 2017 3:06 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 4974
Location: Indianapolis, IN
Yes, please let us know how the project turn out...

John


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Thu 23, 2017 10:29 am 
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We just started breadboarding it. I'll post a pic soon. Fingers crossed!!

Thanks again for all the help!!!


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Thu 23, 2017 3:16 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 4974
Location: Indianapolis, IN
Good---waiting to hear about that moment when power first applied !

John


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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 24, 2017 3:27 pm 
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Quote:
[xrhonda91] Good---waiting to hear about that moment when power first applied !

Not sure about how much power will be applied, John ...

What a piece of junk! ... 50 years later and only 4 volts?!?! :lol:

Attachment:
9volt.jpg
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 Post subject: Re: Graymark 508 - "Boys Radio" ┐(´д`)┌
PostPosted: Nov Fri 24, 2017 5:39 pm 
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Joined: Oct Mon 26, 2009 10:02 pm
Posts: 4974
Location: Indianapolis, IN
Amazing that the original battery had any "charge" left !

But still have four Ray-O-Vac "D" batteries that came in a multi-band radio given me in 1974 that still were perfectly good a couple years ago (need to check 'em again)---the radio was given away long ago, but kept them ! Weren't used much, but held their power...

How long before "switch is thrown" on radio ?

John


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