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 HMV 779 & 30's Astor car radio
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 Return to top of page · Post #: 1 · Written at 12:26:26 AM on 28 October 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

If anyone has a better quality print of the circuit of the AORSM on CD HMV 779 it would be appreciated.
Set has been hacked a bit, but the machinery says the shield is connected to HV winding (1K) & that's not good.

Second is a request for circuit & info on a Astor 1930's Car Radio (stamped April 193_ :Pity stamping is incomplete).

1st RF 78; 1st IF 78; Pentagrid 6A7 (released Jan34) 2nd detector / 1st AF 6B7 (released Jan 34) Rectifier 84; 6V Vibrator type. Remote field coil spkr (stuffed). Remote controls & dial.

Astor car Radio


Marc


 
 Return to top of page · Post #: 2 · Written at 8:25:27 AM on 28 October 2014.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1253

Have the diagram in AORSM 1938, designated HMV 779 B/Cast. The diagram is small (diag and component values half a page) but everything including component numbers and values is legible.

Will scan and send tonight.


 
 Return to top of page · Post #: 3 · Written at 8:43:06 AM on 28 October 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

STC380: Thanks. As said, one I have is hopeless especially when it has been got at and I just have to check everything, despite the transformer being in trouble.

I seem to be having a run on sets that have been messed up by DIY experts, this is the second from the same source, even that it was not the DIY new owner that was responsible for all of it.

I have to take the blame for one Astor I bought for a collector about a fortnight ago. Astor seemed to use the worst grades of rubber, and between it & a hacker, it took a week of spare moments to rewire it & sort it out. Even the IFT's & mains transformers were included.

The point here: Its fine to whinge about the situation, but only action & methodology will fix it, albeit that it will not happen in five minutes. These days with kids, its to easy to replace, or seek instant gratification.

Marc


 
 Return to top of page · Post #: 4 · Written at 9:12:12 AM on 28 October 2014.
Gandhn's Gravatar
 Location: Cameron Park, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 385

The circuit is also in my Vol 3, 1939 and the circuit is quite clear. Between STC's page and this one, you should be OK. Emailed to your inbox.
Harold


 
 Return to top of page · Post #: 5 · Written at 11:22:30 AM on 28 October 2014.
MonochromeTV's avatar
 Location: Melbourne, VIC
 Member since 20 September 2011
 Member #: 1009
 Postcount: 1179

1930's Astor car radios with that valve line-up including a 41 output are as follows:

220/DA, 6 & 12 volt. 1935 to 1937.

6376/EE, 6 volt; 6376F/FD, 6 volt; 12376/FB, 12 volt. 1936 to 1938.

6376S/ED, 6 & 12 volt. 1936 to 1938.

IF for all models is 173kHz.


 
 Return to top of page · Post #: 6 · Written at 7:32:10 PM on 28 October 2014.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1253

My mistake it was volume 3. If there is anything not legible in Gandhn's copy, let us know and I'll scan mine.

The paper in the 1939 number is good quality and hasn't deteriorated. One other I have (1937) is not so good and the pages are literally falling apart.


 
 Return to top of page · Post #: 7 · Written at 7:45:29 PM on 28 October 2014.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

It's interesting to see the internals of a car radio of that vintage. It's not something that I would ordinarily come across or seek out.


 
 Return to top of page · Post #: 8 · Written at 7:50:53 PM on 28 October 2014.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7290

Watch that condenser at the top right. It'll contain PCBs.

A well built machine by all accounts. Almost military spec.


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

 
 Return to top of page · Post #: 9 · Written at 9:59:33 PM on 28 October 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

With thanks, I have now have a readable HMV circuit & can sort the mess while it is decided what to do about the transformer.

The Astor mentioned got taken home, so that's one less in the line.

I did not seek this radio, In the Vintage Car Club here, they know I fix radio's, so it quickly found me. Some newer ones are horrors.

If photo's of the pan of the Car radio are wanted, it can be done. I worked in Chemistry & that cap is not alone in containing PCB's: Some paper types have it as well, e.g. The grey metal clad ones.

Some paper is acidic & you can often smell the Acetic Acid (Vinegar) I have a few books like that. I do make a point of putting Sodium Bi Carb in porous sachets in the containers of books when they have to be stored water proof & vermin proof and in a couple of instruments here that create acid internally.

Marc


 
 Return to top of page · Post #: 10 · Written at 10:25:24 PM on 28 October 2014.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1253

Just noticed that there is a voltage table on the two pages over - did you get that Gandhn?


 
 Return to top of page · Post #: 11 · Written at 10:29:00 PM on 28 October 2014.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

If photo's of the pan of the Car radio are wanted, it can be done.

I think they would be interesting to add to the first post for the record ... although I gather the exact model is still unresolved?


 
 Return to top of page · Post #: 12 · Written at 12:26:00 AM on 29 October 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

The voltage table for the HMV is readable and is needed to repair the transformer after it is stripped down. albeit I have other ways of supplying it in the meantime to get it mobile.

Astor car Radio


Do note the exfoliation & explosion of the block that holds the cover (first photo) die cast does that.

Marc


 
 Return to top of page · Post #: 13 · Written at 8:16:13 AM on 29 October 2014.
Gandhn's Gravatar
 Location: Cameron Park, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 385

Just noticed that there is a voltage table on the two pages over - did you get that Gandhn?

I missed that, but Marc's table is readable (post above), so all is good.
Harold


 
 Return to top of page · Post #: 14 · Written at 8:46:35 AM on 30 October 2014.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

I have pretty much all I need, can't do much about the owner. The other thing that is not clear is the boards albeit I can work around them. I note the 6V6 is as I keep saying, the grid resistors have failed.

Interesting that the missing back bias resistor is at the opposite end of the set to the rectifier & speaker plug and then wires for the CT and an electrolytic run all the way back. Some designs do leave one guessing? I have had to make small mods to a couple of sets this year, for design faults causing feedback, or instability.

Car radio is not in work just yet, need to have a discussion with its owner about some mechanical issues.

Marc


 
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