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 Pye r13 42a
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 Return to top of page · Post #: 1 · Written at 3:09:43 PM on 7 April 2010.
Leroy's Gravatar
 Location: Melbourne, VIC
 Member since 7 April 2010
 Member #: 647
 Postcount: 6

Hi

I've just come across this particular radiogram and I am having a little trouble identifing the valves. So far i've got a
6bm8,6ca4,6n8. There are two I cant ID. They're both Mullards. One says __7k (i think) the other is completly blank. I've looked online for schematics etc but I can find nothing. If anybody has the schematic or knows the full valve complement that would be greatly appreciated.

Leroy


 
 Return to top of page · Post #: 2 · Written at 5:10:54 PM on 7 April 2010.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 5726

G'day Leroy,

A few things will help with identification. If you have a photo of the radiogram you can e-mail it to Brad.mail.vintage-radio.com.au and I will include it in your post for you.

Other helpful information (if it is available to you) would be the brand, model number and approximate age of the unit.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 3 · Written at 10:21:33 PM on 7 April 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3925

More info, as Brad said.

_7k does not compute? not a common symbol last.

So far 6BM8 is the audio output (Triode Pentode)
6CA4 is a heavy rectifier more often found in TV's
6N8 is a horrid dual diode, RF Pentode which could be IF1
A common valve used by PYE was a 6BD7 Duo diode Triode which is unlikely.

The one with 7 is more likely to be the converter 6AN7 which will be close to the tuning gang.

So I would suggest as a wild guess. V1, 6AN7; V2, 6N8; V3; 6N8 or 6BD7; V4, 6BM8; V5, rectifier 6CA4 (6V4)

Marc


 
 Return to top of page · Post #: 4 · Written at 5:18:57 PM on 8 April 2010.
Leroy's Gravatar
 Location: Melbourne, VIC
 Member since 7 April 2010
 Member #: 647
 Postcount: 6

Brad the model number was in the subject heading.
Pye r13 42a

Unfortunatlly all I have is the chassis as the rest was junked.

I'm almost convinced that the tube that I though said 7k must be another 6bm8 as this amp is sterio (two OT's) and i've only id'd 1 power tube. The internal structure of the tube looks very similar as well.

Pics attached
http://i628.photobucket.com/albums/uu2/leroyfromoz/P08-04-10_1655.jpg

http://i628.photobucket.com/albums/uu2/leroyfromoz/P08-04-10_1656.jpg

Leroy


 
 Return to top of page · Post #: 5 · Written at 7:34:13 PM on 8 April 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3925

Ok nice to know it's stereo. That changes things.

6BM8 was common in HMV stereos and yes, if its stereo then it is likely that there are two.

That means that there has to be a converter, which is probably 6AN7, the 6N8 is the detector an probably RF amp and the detector output will feed to both triodes of the 6BM8's.

This looks like it has had the caps changed, or is late 60's early 70's as I see Styroseals.

Do visually check them I have seen several mechanically fail & short.

There is no comment on status: viz. goes, dead, not game to plug it in.

Marc


 
 Return to top of page · Post #: 6 · Written at 9:28:02 PM on 8 April 2010.
Leroy's Gravatar
 Location: Melbourne, VIC
 Member since 7 April 2010
 Member #: 647
 Postcount: 6

The status is unknown. I received it in bits. There is some evidence of heat/fire damage. In all honesty i'm just going to use it for parts (assuming those parts work).
As far as the unidentified small 9 pin is concerned i've compared it to a 6an7a I got out of a Kriesler and they look similar.

Leroy


 
 Return to top of page · Post #: 7 · Written at 10:55:29 PM on 8 April 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3925

6AN7 has 9 pins

Heat & fire damage where? was it in a fire, or was one in it?

If the chassis parts are still assembled, they may still work.
Need further info.

Unlike valve stuff it's "Solid State" stuff that runs on smoke: When it gets out, it's usually stuffed.

Marc


 
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