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Help identifying a 7 pin minature valve
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Return to top of page · Post #: 1 · Written at 12:53:36 AM on 22 March 2011.
	Rob D Location: Perth, WA Member since 23 January 2011 Member #: 820 Postcount: 59
Hi all, The markings have rubbed off this valve. Hoping someone might recognise it. Image Link It has a 6.3v heater and is currently in the modulator section of a am transmitter. Have inspected the internal connections and have come up with the following pinout. Testing with this pinout yields sensible readings on my tester. 1 - g 2 - c + supp. 3 - h 4 - h 5 - a 6 - s 7 - g Pins 1 and 7 are definitely both connected to the grid Cheers ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ Currently restoring Astor HMQ 32vdc Completed and working great!!

Return to top of page · Post #: 2 · Written at 2:48:03 AM on 22 March 2011.
	Gfr53 Location: Harston, VIC Member since 28 February 2009 Member #: 442 Postcount: 145
G'day Rob, 6AQ5. Cheers, Graham...

Return to top of page · Post #: 3 · Written at 3:34:24 AM on 22 March 2011.
	GTC Location: Sydney, NSW Member since 28 January 2011 Member #: 823 Postcount: 6686
^ Looks like the winner!

Return to top of page · Post #: 4 · Written at 4:02:43 AM on 22 March 2011.
	Rob D Location: Perth, WA Member since 23 January 2011 Member #: 820 Postcount: 59
Brilliant!! Cheers lads!! ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ Currently restoring Astor HMQ 32vdc Completed and working great!!

Return to top of page · Post #: 5 · Written at 4:37:02 PM on 22 March 2011.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5253
Sounds good that's about the only common one that has 1& 7 as grid. Unfortunately when the paint comes of some of those the freezer trick will not work.

Return to top of page · Post #: 6 · Written at 4:53:20 PM on 22 March 2011.
	GTC Location: Sydney, NSW Member since 28 January 2011 Member #: 823 Postcount: 6686
^ What's the freezer trick? Something like superglue fumes on fingerprints?

Return to top of page · Post #: 7 · Written at 8:06:32 PM on 22 March 2011.
	Brad Administrator Location: Naremburn, NSW Member since 15 November 2005 Member #: 1 Postcount: 7300
Sometimes it will show a sillhouette of the octagon and valve type number. If this information was painted on the valve with chalky paint or someone has done what I usually do and alco-wiped the valve to clean it then the 'forensics' won't work. In my case I always write down the numbers before cleaning valves and then write the number back on the valve at the bottom with an Artline pen. ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾ A valve a day keeps the transistor away...

Return to top of page · Post #: 8 · Written at 9:28:34 AM on 23 March 2011.
	Marcc Location: Wangaratta, VIC Member since 21 February 2009 Member #: 438 Postcount: 5253
Along Brad's lines. Sometimes in the correct light at angle you can see a feint number (Philips A&B). Depending on what was used to cratethe number? One method is to put the valve in the freezer long enough to cool the envelope. On removal & exposure to humidity the number can often be seen due to the difference in the surface. tension. Do note some philips "P" type actually have the number on the bottom of the socket as well as on the metallisation, that sometimes comes off, but can be repaired to a point.. Marc

Return to top of page · Post #: 9 · Written at 2:40:42 PM on 23 March 2011.
	GTC Location: Sydney, NSW Member since 28 January 2011 Member #: 823 Postcount: 6686
Thanks guys. Good tips!

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