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 1955 breville precedent
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 Return to top of page · Post #: 1 · Written at 4:00:05 AM on 17 September 2011.
Billycamera's Gravatar
 Location: Violet Town, VIC
 Member since 17 September 2011
 Member #: 1007
 Postcount: 28

I have a beautiful 1955 roll top precent which I bought primarity as a furniture item. Having replaced the cord, transformer and caps, it works but is not great; the volume is low and variable. It distorts at a low levlel too. It's a 4/5 valve with what appears to be a 6M5 in the line up (writing has faded from the valve surface). What concerns me is that this particular valve emits no light or heat. Does this make sence? Is this valve the likely cause of my problems? If so how should I go about replacing this rare valve?


 
 Return to top of page · Post #: 2 · Written at 4:27:44 PM on 17 September 2011.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

If the tube was totally deficient of heater it would not emit any noise full stop.

It cannot be ruled out. Low and variable needs to be a little more specific.

Does the change take place slowly & fairly evenly, or is it random & abrupt.

What was the issue with the transformer. I find them to be a vary rare failure unless its a speaker transformer and Krieslers seem to kill them at a steady rate.

Has this unit had the filter & paper caps changed? If not it should have never been turned on in my book until they were. A shorting one of those can drag the power down & cook the power transformer.


Marc

not far away


 
 Return to top of page · Post #: 3 · Written at 10:09:25 PM on 17 September 2011.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 1253

There have been comments previously on the 6M5 which might help. Also maybe a source.

http://vintage-radio.com.au/default.asp?f=3&th=211.

Maybe you have the silver migration phenomenon.


 
 Return to top of page · Post #: 4 · Written at 11:06:28 PM on 17 September 2011.
Billycamera's Gravatar
 Location: Violet Town, VIC
 Member since 17 September 2011
 Member #: 1007
 Postcount: 28

The capacitors have all been changed (the new caps are so small compared to the old ones but the values are all the same or slightly higher).

The filter? You have got me there! What is this thing called a filter?

The old transformer was running hot and looked in poor shape, it drew enough (1/2 amps) to light up a 150 w lights bulb when wired in series but the radio works the same as it did after the transformer was replaced. The new transformer is cool and dosn't light my bulb.

The further reduction in volume became apparent after I turned it off for a few days, not intermitant. Distortion would be acceptable if it was much louder. (May have another go at the caps.)

Will check pins 1 and 2 for silver migration but why is this valve so cold? Maybe it not the correct valve hense the absence of writting.

Speaker transformer has been suspect; what do I replace it with?

In the tuning department the radio is top with excelent MW and short wave reception when hooked up to earth and the electric fence wire (de activated of course)

This radio is the exact same as the NSW premiers on hoarders.com


 
 Return to top of page · Post #: 5 · Written at 12:55:03 AM on 18 September 2011.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

The filters are the electrolytic caps of around 16μF that remove the ripple from the "B" supply rail. Wrong voltage ones can fail.

If that 6M5 has a cathode resistor, check it & if it has a cap across that resistor, it should have been replaced.

I will see if I have a circuit.

Marc


 
 Return to top of page · Post #: 6 · Written at 4:12:47 PM on 18 September 2011.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7290

This radio is the exact same as the NSW premiers on hoarders.com

There is a story on that here.


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

 
 Return to top of page · Post #: 7 · Written at 12:39:02 AM on 19 September 2011.
Billycamera's Gravatar
 Location: Violet Town, VIC
 Member since 17 September 2011
 Member #: 1007
 Postcount: 28

Thanks for all the feedback. I tend to be a bit of a train man and I generally have a better understanding of electro mechanical devices that go click and clunk.

Capacitors are all a bit mysterious so the filter thing got me wondering. No worries Marc I changed them all and they are all rated at 500v.

The radio on hoarders belonged to Premier Urskin.

The world has gone litigation mad eh! All those law men need to find something wrong with everything so they can afford the latest 7 series. We wouldn't want BMW to go broke would we? I wonder if they know about all this at the Violet Town second hand shop? A 1930's radio is for sale there at $50; it is flood damaged!


 
 Return to top of page · Post #: 8 · Written at 1:25:27 PM on 19 September 2011.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

There are circuits in AORSM's but there are a couple of sets for 1955 so it would be an Idea to list what valve numbers are readable & indicate number,

One set is a reflex and will have a horrid 6N8. Do avoid touching numbers, some come off.

One model has a 6X5 rectifier (8pin) & they are notorious for going short.

There may be a number stamped into the chassis. There is another guy in your town that is a member of the Vintage Radio Club of NE Vic. He may be able to help?

(Plug) The Meeting is in Shepparton Saturday 24th.

Marc


 
 Return to top of page · Post #: 9 · Written at 4:48:47 PM on 20 September 2011.
Billycamera's Gravatar
 Location: Violet Town, VIC
 Member since 17 September 2011
 Member #: 1007
 Postcount: 28

Thank Marc
Does the 5m6 have parrallel heater windings?
Maybe one or more heaters have blown; there is something burning in there but not much.
Ive just put in a new speaker transformer and redone the elerolytics (only Two) and scored the valve bases around the pins.
It sounds quiet nice but its still too quiet.
Have slipped a little cover over my 5m6 to trap the heat in a bit, it may have improved things just a little.
V46087 is the number stamped on the chassis.
No471447 is the number on the ARTS P sticker.
Is it possible for the resistors to wander out of range?
Thank Guys
VT bill


 
 Return to top of page · Post #: 10 · Written at 5:08:03 PM on 20 September 2011.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5239

If the set runs, albeit, badly. The heaters have not blown.

However, that is not to say one of them has not developed a heater to cathode short .

That is normally garanteed to fry something like cathode resistors, decoupling resistors, back bias resistors & transformers.


The fact that something is burning is a guarantee that something is not right and the set should not be run until it is determined what is burning & why?

It is possible for a new filter cap to be reverse polarity: as an example.

I (and others) need a list of all of the tubes so that we can try to get the circuit thereby limiting the speculation & generalisations.

If you are completely bamboozeled you may need to consider a trip to Wangaratta / Shepparton.

Marc


 
 Return to top of page · Post #: 11 · Written at 7:15:42 PM on 20 September 2011.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

"The radio on hoarders belonged to Premier Urskin."

Never heard of him.

Please post a link to that hoarders item.


 
 Return to top of page · Post #: 12 · Written at 8:35:30 PM on 20 September 2011.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7290

Closest to that name would be Sir Robert Askin, Premier of New South Wales between 1965 and 1975.

I checked hoarders.com and was redirected to a link farm and then tried http://hoarders.com.au/ but couldn't confirm the Premier's name.


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

 
 Return to top of page · Post #: 13 · Written at 9:36:03 PM on 20 September 2011.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

The only rolltop Precedent radio I could find on hoarders.com is what is described as a 1940s model owned by former Prime Minister Sir Arthur Fadden:

http://hoarders.com.au/40s-breville-precedent-rolltop-radiogram-record-player.html.

Fadden was only PM for the very short period (28 August 1941 to 7 October 1941) between Menzies' resignation and Curtin's election.


 
 Return to top of page · Post #: 14 · Written at 8:34:01 AM on 21 September 2011.
Billycamera's Gravatar
 Location: Violet Town, VIC
 Member since 17 September 2011
 Member #: 1007
 Postcount: 28

Its OK Marc there is no smoke.The 6M5 is working but only the faintest glimmer of light and heat.

Have cleaned the valve sockets with a tip cleaner and it sounds much sweeter,its just as the volume creeps up things sound a bit scatchy, over the last 24 hrs the sound has actually improved with use.

I must confess I had new caps around the wrong way awhile back but now its sorted with new caps. The new hammond transformer seems to be protcted. Maybe a new rectifier valve is needed though it too works.


 
 Return to top of page · Post #: 15 · Written at 8:59:23 AM on 21 September 2011.
Billycamera's Gravatar
 Location: Violet Town, VIC
 Member since 17 September 2011
 Member #: 1007
 Postcount: 28

Thank you Marc
I may take up on the offer to visit you with the unit.
Im free mid week; weekend I'm a very busy person.
0417330871
Mcfadden sounds right.
I wonder if Joan Kirner has any old radios, I will have to ask her.

Bill Fisher


 
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