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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 19th Aug 2018, 2:24 pm   #1
ukcol
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Default Mazda AC/SP1 valve data sheet error.

The manufacturer's data sheet for this valve is available from these two sources.

https://frank.pocnet.net/sheetsA.html

and

http://www.r-type.org/exhib/aaa0494.htm

In this document the base connection details are incorrect.

The correct connections are available from the radiomuseum site.

https://www.radiomuseum.org/tubes/tube_acsp1.html
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Old 20th Aug 2018, 6:17 pm   #2
WME_bill
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Default Re: Mazda AC/SP1 valve data sheet error.

Surely the connection data is not as doubtful as you suggest.
Both FrankPhilipse and Mazda data sheet give the connections starting from pin1 as the top pin above the two widest apart pins on this British Seven Pin Base. These convention seems to be followed also by Philips and Brimar for the B7 base.
The Radio Museum follows a different convention, and starts pin1 as the bottom right pin at the narrowest part. Both looking onto the base, and counting clockwise.
The electrodes are in the same sequence. So use either, just decide where to start counting.
None of the old bases I have show any pin numbering.
wme_bill.

Last edited by WME_bill; 20th Aug 2018 at 6:27 pm.
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Old 20th Aug 2018, 6:32 pm   #3
ms660
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Default Re: Mazda AC/SP1 valve data sheet error.

The National Valve Museum page for the AC/SP1 gives the same connections as the Radiomuseum if I remember rightly, but the linked PDF (Mazda,Ediswan) data sheet from that page shows no TC electrode connection and no g2 electrode connection.

Lawrence.
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Old 20th Aug 2018, 6:54 pm   #4
Boater Sam
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Default Re: Mazda AC/SP1 valve data sheet error.

ACSP1.

My book starts the numbers in the head pin1 which is opposite the two closest together. Then numbers round clockwise.

That gives the connections 1 to 7 as metalization, grid, suppressor grid, heater, heater, cathode, and screen grid with anode on the top cap.

That puts the heaters on the 2 closest together pins, 4 & 5.

Sam.
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Old 20th Aug 2018, 7:16 pm   #5
ukcol
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Default Re: Mazda AC/SP1 valve data sheet error.

Yes, as Lawrence has pointed out, it's not about drawing convention.

The Mazda sheet is in error because it doesn't assign a screen grid connection (which should be pin 7) and it doesn't show a top cap connection at all (which in fact is anode).
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