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 Post subject: Precision Signal Generator E 200 C
PostPosted: Feb Fri 03, 2012 8:49 pm 
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Recapping this. How come the picture in the schematic is different and the schematic shows tube numbers 6AU6, 6U8 and 5Y3. The tubes in mine are 6SJ7, 6C5 and 80. Would the location and value of the parts be the same? Another problem is the E cap. It has no markings at all on it. It is a 3 section 10/10mfd @450 and a 25 mfd @75. I think if the schematic i am using is correct. Does one 10 mfd go to the 5Y3 (80?) another 10 to terminal 4 on the transformer and the 25 mfd to terminal 3 on the transformer?
Stan Ski
The serial number on this generator is 21758


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Fri 03, 2012 10:01 pm 
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Location: Livermore, CA
Hi Stan

There are many revisions of this signal generator. An 80 is same as octal 5Y3. A 6SJ7 is close to miniature 6AU6. A 6C5 , triode, and 6U8 are different. A 6U8 is a triode with pentode. This section of the circuit will be different unless part of the 6U8 isn't used..

A section of an electrolytic filter, positive lead, will connect to filament of 5Y3/80.

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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sat 04, 2012 1:32 am 
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So does anyone know where i can get a schematic of this revision of this precision tester.
Stan Ski


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sat 04, 2012 1:37 am 
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Stan

This may be what you already have but Precision E 200 C series is listed here:

http://www.nostalgiaair.org/References/Manuals/

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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sat 04, 2012 2:24 am 
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Yep, That is what i have
Stan Ski


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sat 04, 2012 2:36 am 
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STAN:
Email sent.
BOB


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sun 05, 2012 11:20 pm 
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Bob, Sent me the correct schematic. Would you guys please confirm i am wiring the e caps correctly. It takes 3 caps. Two 10s @ 450 and a 25 @100 volt. C4 A, B, and C. What i am seeing is one 10 goes to filament of the 80 tube ( Grey ? wire) .Another 10 ( Gold wire) goes to the large green 3k resistor and the 25 goes to terminal 3 on the transformer (green wire) . All 3 use chassis as negative. This should be a simple one but i just want to be sure.
Stan Ski
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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sun 05, 2012 11:36 pm 
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Stan

I agree with some but only C4A uses chassis as negative. C4B and C4C use center tap of the high voltage winding as negative. Just go by the schematic.

C4A and C4B are high voltage. C4C would be the 25 mf @ 100 volts. Values are not called out in the schematic.

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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sun 05, 2012 11:40 pm 
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http://antiqueradios.com/forums/viewtop ... 8&t=140159

Stan, the above thread explains all. Two summers ago I had the same problem, except the caps were missing. It was my first inquiry to this forum, and I continue to marvel at the extent of the knowledge which is willingly shared.

At the end of the second page after the members had answered my question, I eventually found the correct schematic, with the polarity marked.

Your schematic (the same one I was using) does not show polarity of the filters.

Thanks to all again,

Bill


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Mon 06, 2012 1:14 am 
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Norm, Now i see where the negatives are. Bill, Thank you for posting the other post on this. Sure did explain things to me. At least i don,t feel like some kind of idiot as i see i was not the only one that found this to be more then a little confusing. Have all the other caps installed so tomorrow i will install the e caps. Lets see positive goes to chassis but not always . Oops, I meant negative goes to chassis but not always but maybe sometimes. Sure am glad it is all straightened out in my giant brain. I do know that being positive is a good thing. Thanks again guys.
Stan Ski


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Mon 06, 2012 2:32 am 
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Stan

Believe easiest way to remember, center tap of a high voltage winding is most negative point in a radio. If in doubt negative of a cap connects here. You have one between CT and chassis. In this case chassis is positive.

This is true for US made radios. Foreign radios can be different.

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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Mon 06, 2012 3:08 am 
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I have the same signal generator, and found half of the wire-wound AVC pot was burned up. Someone must have connected a high voltage to the AVC output. I haven't found a replacement WW pot with switch, so I put a fixed power resistor in for the supply. I have no need for clamping the AVC voltage anyway.
Don


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Mon 06, 2012 9:04 pm 
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OK. I have read all the threads on this. Maybe to many times as it is giving me a headache. Just to be sure i am posting another picture and will explain where i am putting the e caps. C4A + going to one side of R11 (green resistor) . Negative going to chassis
C4B + going to other side of R11 ( green resistor). Negative to center tap
C4C + going to blue wire that goes to the AVC control. Negative going to center tap.
Center tap on transformer is terminal 3.
Please tell me i am correct
Stan Ski
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Last edited by Stan Ski on Feb Mon 06, 2012 9:33 pm, edited 1 time in total.

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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Mon 06, 2012 9:13 pm 
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It seems you have swapped positions for C4A and C4B.
C4C is correct.
Don


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Mon 06, 2012 9:35 pm 
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BikenSwim wrote:
It seems you have swapped positions for C4A and C4B.
C4C is correct.
Don


So i did. Had it written down and still typed it wrong
Thank you
Stan Ski


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Tue 07, 2012 11:39 pm 
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Got all the caps replaced. Plugged it in and no smoke! Still have to check the resistors and install a new line cord. Hope to test it out this week. Would like to say a big THANK YOU for all the help on this thing
Stan Ski


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Tue 07, 2012 11:59 pm 
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R1, the resistor that produces the Low output, is hidden in the front panel between the output jacks. Mine was bad. You may want to install BNC connectors to use modern test lead cables.
Don


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Wed 08, 2012 11:02 pm 
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Don, Checked all the resistors and there were none that were really out of spec. Have two problems the resistor you are referring to i cannot see. I see it on the schematic and it should be coming off the low side of the output terminals. It is not there! Also i have another that is part of the band switch. Not sure were it is located on the schematic and can,t read it because it appears to be a solid brown. It is the brown one in the last picture. It is measuring 45.5 K. Any help? Hope the pictures explain things better. I like your idea of the BNC connectiors and will install them.
Stan Ski
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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Thu 09, 2012 7:02 am 
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You can measure from the center pin of the low to the center pin of the high output to see if R1 is close enough. It does not need close tolerance since it is fed from a variable output anyway. I don't think I changed any other resistors either.
Don


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 Post subject: Re: Precision Signal Generator E 200 C
PostPosted: Feb Sat 11, 2012 7:35 pm 
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Here is the reason i could not see R1 resistor. It was hidden inside the low side of the RF out. You can see it in the picture on the left. Wonder what idiot did that? it was reading about 5k so i replaced it
Stan Ski
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