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 Scharnberg Strauss model 41 circuit diagram
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 Return to top of page · Post #: 1 · Written at 4:05:16 PM on 13 July 2014.
SteveO's Gravatar
 Location: Stanmore, NSW
 Member since 6 July 2014
 Member #: 1599
 Postcount: 29

Hi Guys,

I have a Scharnberg Strauss model 41 with a few problems. Does anyone have a circuit diagram? Anyone have one of these receivers?

Steve


 
 Return to top of page · Post #: 2 · Written at 4:14:36 PM on 13 July 2014.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6012

I don't have anything for Scharnberg Strauss. Schematics and information generally for that brand are hard to come by.

You could try contacting the SA branch of the HRSA:

http://www.hrsasa.asn.au/.


 
 Return to top of page · Post #: 3 · Written at 4:51:25 PM on 13 July 2014.
Gandhn's Gravatar
 Location: Windella, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 343

I have 4 of this model, with 2 different valve line-ups, but unfortunately I can't help with a circuit. I was able to get mine operational from basic principles.
What is the problem with yours, as I may be able to compare it with mine. What valves does it use?
Harold


 
 Return to top of page · Post #: 4 · Written at 9:40:27 AM on 14 July 2014.
SteveO's Gravatar
 Location: Stanmore, NSW
 Member since 6 July 2014
 Member #: 1599
 Postcount: 29

Thanks Guys, appreciate the comments. I think I'll join the historical radio as well. The set works but has a hum so I'll start with replacing the caps etc. Harold, I'll check the valves and get back to you. You should see the state of this one, very rusty chassis and full of dust but still works!!! I will take a few photos as well. I'm on leave at the moment so give me a few days to send the info.

Steve


 
 Return to top of page · Post #: 5 · Written at 2:28:16 PM on 14 July 2014.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1133

I've been doing a bit research in to the Scharnberg Strauss brand. Scharnburg Strauss was the house brand for Ernest (not Ernst) Smith & Co, wireless retailers, who later became better known as Ernsmiths.

Prior to 1931 Ernest Smith & Co. were builders, building contractors and land agents. In late 1931 Ernest Smith & Co. started dabbling in wireless and gramophone sales. The Scharnberg Strauss brand was born in late 1931. In March 1932, a new company was registered under the name of Ernest Smith & Co. for the purpose of wireless manufacturing, sales and the general "exploitation" of the wireless industry in South Australia. Ernest Smith & a relative were named as first directors for this company.

A year later in 1933, Ernest Smith & the same relative were named as first directors in a new company which had strong links to Radio Corporation of Australia (Astor).This new company, National Radio Corporation of South Australia, manufactured radios under the National brand and also sold unbranded radios and chassis for other South Australian retailers. National Radios also had a lot of similarities to Astor sets, using Astor parts and having the same or similar circuits.

Going by the involvement of Ernest Smith with National Radio Corp at a directorial level and the fact that Ernest Smith & Co. were not licensed by the ARTS&P to manufacturer radios (National Radio were), it is likely Scharnburg Strauss radios were at least for some time manufactured by National.

Looking at the pictures of the Scharnburg Strauss 41 on Radiomuseum, the chassis has quite a resemblance to Radio Corporation types from the post war like the DL, KL & KM. Even the power transformer looks like an Astor type. This is not to say the 41 is the same as a National or Radio Corp type, but there may be some similarities or even clues for restoration work. As we know, Scharnberg Strauss schematics appear not to exist.


 
 Return to top of page · Post #: 6 · Written at 5:09:39 PM on 14 July 2014.
Gandhn's Gravatar
 Location: Windella, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 343

The model 41 radios on Radiomuseum are two of mine and I an currently restoring a table top radiogram. When the cabinet is finished, I will list it there, as even less is known about it.
They are an interesting brand, with their commercial structure reasonably well known, but an absolute dearth of technical info.
Harold


 
 Return to top of page · Post #: 7 · Written at 4:53:51 PM on 19 July 2014.
SteveO's Gravatar
 Location: Stanmore, NSW
 Member since 6 July 2014
 Member #: 1599
 Postcount: 29

Hi Harold,

I had a look at the valves. From the left looking at the chassis from the rear:

6A8G
EBF35
The big one has no number
5Y3GT

There is a photo of a similar radio in radiomuseum but the large valve is in a different position. This set works....just. Doesn't work with these valves swapped around (heaters don't light).

Is this like yours? How can I post a photo here?


Steve


 
 Return to top of page · Post #: 8 · Written at 5:09:07 PM on 19 July 2014.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6349

How can I post a photo here?

Just e-mail it to me Steve. Click my username for my addess. Smile


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

 
 Return to top of page · Post #: 9 · Written at 6:33:21 PM on 19 July 2014.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1133

I too would be interested in seeing some photos including some of underneath the chassis.

The valve line-up is of interest. Harolds Radiomuseum set and another set I saw had a ECH35 instead of a 6A8G. The other set I saw used a EL33 output, where as Harolds uses a 6V6GT.
ECH35 is a triode hexode and the 6A8G is a pentagrid.

There may have been changes during production, or someone might have gotten at it at some stage.

Also a question: does the model 41 have a filter choke?


 
 Return to top of page · Post #: 10 · Written at 12:18:46 AM on 20 July 2014.
SteveO's Gravatar
 Location: Stanmore, NSW
 Member since 6 July 2014
 Member #: 1599
 Postcount: 29

Ok photos are here, I'll see if I can work out if it has a filter choke.

Scharnberg Strauss Chassis
Scharnberg Strauss Chassis
Scharnberg Strauss Chassis


Steve.


 
 Return to top of page · Post #: 11 · Written at 9:53:28 AM on 20 July 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4344

Really this set should not be powered those electrolytics are liable to present a s a short & burn the transformer winding out & swapping valves willy nilly can destroy them.

A little bit of detective work will tell you what the OP tube is often, by the cathode resistor. unless its back biased. When there are 3 electrolytics, which is common of Philips if one is positive to chassis its back biased & Astor rarely used that cap that way. otherwise its liable to be the cathode bypass & belongs to the OP tube.

HMV was one that used that labarinth type air trimmer.

What do you propose doing with that chassis? To me it looks like a strip down job.

You need in that case to check the transformer, to see if the moisture as not killed it and that will affect the hip pocket.

I have repaired sets with no circuit, but be prepared to have to draw it.


Marc


 
 Return to top of page · Post #: 12 · Written at 11:18:06 AM on 20 July 2014.
Gandhn's Gravatar
 Location: Windella, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 343

The 41 chassis does use a filter choke, it is the part with a rusty rectangle of iron holding it in, just under the speaker, yellow wire showing. This agrees with all my 41s.
The valve discrepancy with the 2 right hand valves from a back view, is most likely the use of a "G" or a "GT" type valve, where the operation is identical, only the shape. The GT stands for Glass, Tubular and the G specifies a glass valve, but the bigger shape.
Monochrome, on further inspection, one of mine uses an EL33. The output transformer is 7000 ohms, suggesting it is original, as the 6V6 would be 5000 ohms.
They are a nice little set and well worth some effort to restore.
Harold


 
 Return to top of page · Post #: 13 · Written at 12:02:28 PM on 20 July 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4344

ECH35 and 6J8 (Feb 1938) tended to get interchanged. Tasma tended to use Philips valves. 6A8 and 6J8 will in many cases work in the same hole. But on a set like an Astor JJ and and a few others, the 6J8 will cause the band to be compressed.

After 1938 6A8 was normally confined to BC only sets, whilst 6J8 with its Triode exciter, dominated in SW sets.

EL33 has a higher gain than 6V6 and the bias is about half that of a 6V6, that is why I mentioned cathode resistor. As, if the valve is self biased that is a big clue.


Marc


 
 Return to top of page · Post #: 14 · Written at 5:05:03 PM on 20 July 2014.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1133

The unknown output valve looks like a EL3NG or something similar. It is definately cathode-biased - you can see the 25μF electrolytic (smaller one in pic) off pin 8.

What are the values of the 2 other electrolytics?

I've been looking at some Astor service manual parts list and some list 7K OP transformers for use with 6V6GT's.


 
 Return to top of page · Post #: 15 · Written at 5:41:50 PM on 20 July 2014.
Gandhn's Gravatar
 Location: Windella, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 343

The radio I have been looking at (ECH35 converter) is the one with an EL33 output valve, ref my post #12, and it has back bias with the cathode connected to ground. The HT voltage is only about 190 V with the transformer secondary 290 V a side, but volume is good and the radio works well.
It is the same chassis as Steve's but his seems to have quite a few more components than mine, so maybe there were some circuit changes along the way. Apart from replacement caps etc. my wiring looks original.
Harold


 
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