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 Post subject: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Mon 24, 2014 4:52 pm 
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Location: far western end of Maryland...21561
(Big edit)
The "packaged electronic circuit" is in a 60's vintage HH Scott tube receiver ( They are used in a lot of things so posting here rather than audio forum)
It is marked "PEC 38K" and has the number 1346409 on it ) Per Brians info below this means it was a Centralab part made in 1964). The schematic for the receiver shows the component types (resistors and caps) but no values. It is not marked with the brand name but between Brian's info and the fact that the info Dave provided showed that a Sprague # 38 is not the same part it's pretty certain it's a Centralab. I want to replace it with individual parts but need the values. I have heard there are books/catalogues of these things that have the values but have been unable to come up with the info; I suspect if it's in any data it will need to be 60's vintage data.

( to anticipate the "they never fail" response...if fail means burst into flame, probably not. But the resistors do drift and this part , actually 2 of them, is in the signal path from the tuner to the amp.
The Scott 345 receiver is not similar enough ( tube wise) to other scott receivers to allow using a "non-PEC" receiver as a part value guide

Thanks

Andy


Last edited by AB on Feb Wed 26, 2014 5:14 pm, edited 1 time in total.

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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Mon 24, 2014 6:25 pm 
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I think you will have to make a sketch the module, showing the terminals and which components are connected to the terminals. Then you will have to look at the Centralab Catalog and compare the layout to the couplate schematics in the catalog. You are probably looking at 'house numbers' on the module in your HH Scott. The numbers you cite do not show up in a cross reference to the Centralab numbers or in the main catalog. It may also be a custom made module.


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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Mon 24, 2014 9:38 pm 
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Location: Pocasset, Cape Cod, MA
I checked my Centralab PEC Guide and that number is skipped. There's only one listing for Scott also and that isn't it. Centralab used "PC" numbers (even though it's a "PEC" guide) so yours may have indeed been a Sprague number.


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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 2:34 am 
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The number 1346409 indicates that it was manufactured by Centralab in the 9th week of 1964.

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Sarasota FL
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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 2:41 am 
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What's its function? May have been used in other Scott products. Sams usually showed the part values in the PECs, but the 399 is only Scott receiver that they covered in full.


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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 2:45 am 
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They do fail. I've replaced a couple where a resistor had opened.

My approach was to find a schematic from similar set - discrete not couplate. Select a circuit which uses same tubes. Then sketch up which components are needed and then hook it up.

Have fun


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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 2:54 am 
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When you wrote "60s vintage" the thought crossed my mind that my Guide might be too old, but I forgot to check. It's No.5, from 1958. Presumably you want to find a later version.


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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 7:05 am 
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AB wrote:
The schematic for the receiver shows the component types (resistors and caps) but no values.

If the print shows the couplate components inside a dotted lined box, with their connection numbers, then you know where the resistor and capacitor leads terminate, for the most part.

You can measure the resistance values with a meter, and if you have either a capacitance meter or RLC bridge, the caps as well. For a completely internal component with no outside lead, it would have to be a guess. AFA capacitance values though, they would be small, equivalent to those on small disc ceramic caps.

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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 9:26 am 
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I have a listing for a PEC 38. PM me with your email and I will send it to you.

Dave


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 Post subject: Re: Need component values for Sprague (?) PEC/couplate
PostPosted: Feb Tue 25, 2014 12:38 pm 
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Thanks to all for the suggestions and info but still looking.....It will likely be in a 60's (not 50's) dated Centralab document if it's anywhere



Thanks
Andy


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Wed 26, 2014 5:17 pm 
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As edited above, the search continues

Thanks

Andy


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Wed 26, 2014 8:17 pm 
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Location: Middlesex,NJ
HI:

THE MAKE AND MODEL PLEASE.

THIS COULD BE FOUND IN SAMS PHOTOFACT SCHEMATIC AND PARTS LIST.

WALTER-W2WIQ


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Wed 26, 2014 9:52 pm 
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Location: far western end of Maryland...21561
the make of the "stereo" receiver is H H Scott

The model is 345

Note there are 3 different PEC #'s in the thing, the # I am looking for is 38k. It has 3 leads ( there are 2 of them in the receiver).

Thanks


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Thu 27, 2014 2:06 am 
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AB:

Looking at the schematic, I am not sure that "38" is the actual number of the PEC. I think it is possibly referencing a 38 KC de-emphasis filter. The note on the schematic reads: "PEC 38 KC". I imagine usable component values for this function could be found in most any stereo receiver schematic.

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Tim

"One of the advantages of being disorderly is that one is constantly making exciting discoveries." A. A. Milne


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Thu 27, 2014 3:18 am 
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Location: Middlesex,NJ
HI:

HERE IS THE LINK TO H.H SCOTT SCHEMATICS.

http://www.hhscott.com/database/vhhs_00011.html

MY EYESIGHT IS NOT VERY GOOD BUT MAYBE YOU CAN POINT IT OUT AND WHAT PAGE.

WALTER-W2WIQ


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Thu 27, 2014 3:47 am 
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Location: South of Richmond, VA 25 miles down the pike.
Walter,

http://www.hhscott.com/pdf/345.pdf

Page 1 for both, on the right side. Bypass network?

Bill J.


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Fri 28, 2014 5:23 am 
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The answer may be here:

http://www.ebay.com/itm/VTG-Centralab-P ... 2a376915be

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Dale


http://www.dalesantiqueradio.com/


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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Fri 28, 2014 7:29 am 
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Quote:
The answer may be here:

It might be, but that is some crapshoot for $15 plus shipping. I already looked in issue No. 7 and it was not in there, nor was the 222 also used elsewhere in that set. But it is your money and, at least, radiodale and the rest of us are still trying. There also does not appear to be a Sams, even in their bound volumes, to find a cross reference to or a breakdown of its components.

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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Fri 28, 2014 10:14 am 
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AB wrote:
It is marked "PEC 38K"

The schematic for the receiver shows the component types (resistors and caps) but no values.

AB wrote:
It has 3 leads ( there are 2 of them in the receiver).

If it only has three leads, presumably one for ground, then it can't have too many components, and you said above that it ID's their types.

The capacitance values would be very small, such as you would find in disc caps, and the resistance might be measurable.

Exactly how many resistors and capacitors does the print show the couplate having? Can you post it's schematic?

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 Post subject: Re: Still Need component values for Centralab PEC/couplate
PostPosted: Feb Fri 28, 2014 2:44 pm 
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Location: far western end of Maryland...21561
* If you would like to look at the schematic, the easiest/best thing to do is use the link another responder posted above.

* the PECs in question b(#38 K) have 2 resistors and 3 caps.

* given the way it is "wired" it would be impossible to measure any individual component without destroying the thing, in any case that would only tell me what it now is, rather than what it is supposed to be.

I have replaced these things before, when I had the design values, using resistors and dipped silver/mica caps. It works out fine. The receiver "works" as is, I just wanted to have the proper spec part in this rather critical spot.

Thanks for all the input/suggestions from everyone

Andy


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