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 Post subject: Need schematic
PostPosted: Sep Fri 27, 2019 3:19 am 
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Joined: Feb Wed 15, 2017 11:49 pm
Posts: 254
Location: Kingsville, OH 44048
Hi to everyone. Haven't been on for a while. To much going on in the summer.
Anyway, my neighbor brought over a radio his brother found in his mother's house and wondered if I could get it playing again. So of course I said ABSOLUTLY. Problem is I can't find a schematic. It's a Lafayette Table model D49 according to the stamped tag on the back of the chassis. I checked Radio Museum and got the exact picture of the radio and the year and a lot of info but no schematic.
It's a Lafayette D 49. !938 model. Tube layout is 7 tubes: 6A7 6D6 76 6Q7G 6G5 6V6G 80.
The alternative name is Wholesale Radio.
I checked Nostalgia air and Rider books online and can't find anything.
If anyone has any ideas I would greatly appreciate any help.

Thanks ahead of time

Dick


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 Post subject: Re: Need schematic
PostPosted: Sep Fri 27, 2019 11:43 am 
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Joined: Apr Sun 01, 2012 9:55 pm
Posts: 10641
Location: Seattle, WA
I find one schematic in RadioMuseum that uses that tube lineup. It's not the same as yours because it has pushbutton presets. But if you ignore that, it may be the same otherwise. You'd have to check it against your chassis layout.

It's the Coronado 735, here:
https://www.radiomuseum.org/r/gamble_sko_735.html

_________________
Rodney -- KG7EPW
Measure it with a micrometer, mark it with chalk, cut it with a chainsaw.


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 Post subject: Re: Need schematic
PostPosted: Sep Sat 28, 2019 1:09 am 
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Joined: Feb Wed 15, 2017 11:49 pm
Posts: 254
Location: Kingsville, OH 44048
Thank you very much Rodney! Yea I checked the chassis layout and it matches perfectly in a mirror image. On the second page it shows the tube layout and on this chassis the layout is exactly opposite or maybe the picture they use is meant to be seen from the bottom because they show the pin numbers. Anyway same tubes.
So how would Lafayette be in business with the Gamble Skogmo Co. Just wondering?

I'm not getting into this radio for a month or two so I'll report back if help is needed.

I appreciate this forum very much for keeping my addiction active. Thanks again!

Dick


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 Post subject: Re: Need schematic and help
PostPosted: Nov Tue 05, 2019 12:48 am 
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Joined: Feb Wed 15, 2017 11:49 pm
Posts: 254
Location: Kingsville, OH 44048
Hi All,
Don't know if I should add on to this thread or not but here goes.
As stated above I'm now working on a Lafayette D49 table model. Thanks to Rodney he set me up with the only schematic close to this radio. I did find a better copy of the same schematic at nucow.com. It's Rider Vol. 9 Page 402. I can't get that PDF to paste on this thread(not real tech savvy).
But anyway when I took a look at the bottom this chassis it was cram packed with house insulation. After cleaning that out I saw the mice were very busy with the wire insulation. And also someone had been in this radio before. The Ecaps had been changed and there were 2 wires(1 from the 76 osc. tubes plate and 1 from 1 of the 6 coils in this set) that were cut and just wrapped together. B+ was a floating mess.
Now if you found the schematic you can see there is not much info on it. No voltages or location of components and hard to read parts list. No resistance figures for coils or transformers.
So I recapped and checked resistor values and changed any that were out of spec. I found that 2 of them(R1 and R2) did not come close to matching the schematic. R1 was supposed to be 15k-1watt and it was a dog bone yellow,green, orange or 45k-1watt. R2 turned out to be brown, black, orange 10k-1watt. Checked all coils and IFs resistance, all were good except 1 coil that the mice ate through the thin wire but after experimenting with jumpers I think I have that going to the right terminal.
I powered it up o my variac and R2 started smoking. Shut it off immediately and checked all wiring, couldn't find anything wrong.
Also this chassis has 6 coils and I'm having trouble figuring out which is which. I'll try and load a picture when I figure out this new phone I got.
I would appreciate any help and advise from you sages.
Thank you in advance
Dick


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 Post subject: Re: Need schematic
PostPosted: Nov Tue 05, 2019 2:42 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3359
Location: Seattle WA US
Dick-
Those two wires wrapped together may have been intended as what we call a "gimmic" capacitor. Its a traditional and effective way to make a variable capacitor of 5 picofarads or less. Twist more to increase C, untwist to reduce C. Its often used to couple the CW oscillator (BFO) to the detector circuit in a superhet radio. It also could be used to adjust the feedback in an oscillator or the regeneration in a regen detector.

-Chuck


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 Post subject: Re: Need schematic
PostPosted: Nov Tue 05, 2019 4:03 am 
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Joined: Feb Wed 15, 2017 11:49 pm
Posts: 254
Location: Kingsville, OH 44048
Thanks for the reply Chuck.
I've seen that gimmic cap used on a little Airline tabletop radio but it was very short. This had the 2 wires about 3" long wrapped or twisted 3 times. There is no note of that on the schematic, but I'm going to replace it and test.
That wouldn't have any thing to do with too much current going through B+ at R2 would it? I know you are going in this blind without some pics and I'm trying to get this phone synced with this computer with little success.
Thanks again

Dick


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 Post subject: Re: Need schematic
PostPosted: Nov Tue 05, 2019 4:23 am 
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Joined: Feb Wed 15, 2017 11:49 pm
Posts: 254
Location: Kingsville, OH 44048
Well I think I might have a pic
Attachment:
IMG_20191104_172029023_BURST000_COVER_TOP.jpg
IMG_20191104_172029023_BURST000_COVER_TOP.jpg [ 879.92 KiB | Viewed 194 times ]

You can see the 6 coils in this picture. I'm trying to follow the sch and actual wiring to determine which coil is which. There is too many wires of the same color so it is a bit confusing.
Here is a picture of the schematic that I'm using . It's actually the schem. for a Coronado 735 but it has the same tube lineup just not the push button assembly. I don't know how well this will come out but here it is.
Attachment:
IMG_20191104_172906192_BURST001.jpg
IMG_20191104_172906192_BURST001.jpg [ 631.14 KiB | Viewed 194 times ]


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 Post subject: Re: Need schematic
PostPosted: Nov Tue 05, 2019 12:59 pm 
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Joined: Jan Mon 18, 2010 2:13 am
Posts: 19364
Location: Dayton Ohio
madsowry wrote:
So how would Lafayette be in business with the Gamble Skogmo Co. Just wondering?


They aren't.
Your radio was manufactured by a 3rd party manufacturer which made them for both Lafayette (which was a mail order company) and Gambles Department Store (Gamble-Skogmo)
It was probably manufactured by Warwick.

-Steve

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-Pre-War FM
Consoles and floor models, the bigger, the better!


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