Astrad Solar Tuning Knob Help needed - UK Vintage Radio Repair and Restoration Discussion Forum

wireful3 · 21st Jul 2009, 12:09 pm

I hope this is the right section it is more mechanics than circuit, if it is wrong Mods please move it.

I have an Astrad Solar with the FM tuning seized. Tuning is two concentric knobs the inner one for AM and the outer for FM. The inner is fine and uses the FM shaft as a bearing for the mechanics. Looking at the mechanism I assume the FM shaft which is a tube with a shaped drum for the drive cord is intended to rotate freely also but it does not. The first question is am I right in this guess? If not it is a major mystery!

It looks as if the thing has had rough time in the past. The part of the FM tube that the tuning knob presses on to is broken by the force of trying to turn it. I have dismantled things and the part in question is the front plate of the assembly. The tube goes through a hole in this plate and then the whole lot is supported with a top hat section to the rear.

The outer tube for the FM tuning is so rigidly fixed in the front plate hole it seems as if it was shrunk fit. It looks like a casting of Mickey Mouse Metal that is now very brittle. I think I have heard that this is not very stable in size and can shrink. Could this have expanded?

If I am right, I need to find a way of freeing the thing so that I can expand the hole a bit. Penetrating oil overnight had no effect but because of the fragile nature I have only used finger force to try to turn it. Can anyone suggest ways of freeing it?

I will try to add a picture but my attempts in the past have been useless which is why I gave such a long description.

Thanks in hope

ekcobeach · 21st Jul 2009, 3:41 pm

Hi John, No help i'm afraid but i have two of these Astrads.One is perfect but the other has the exact same problem that you mention.I'm afraid i tried just about everything to unseize to damn thing but to no avail.In my frustration i resorted to a pair of Mole grips.Even they wouldn't budge it.I ended up chucking it in a box and bunging it in the shed. I hope someone comes up with something constructive for you.I'm past trying with mine.I'll watch this thread. Regards, Colin.

wireful3 · 21st Jul 2009, 3:52 pm

Hi Colin, Thanks for the comment. It has helped, because you have confirmed I am trying to do the right thing. I will wait a while before getting frantic.

It's amazing, I guess if they had intended to make a press fit bearing, it would have fallen out just by looking at it!

howard · 21st Jul 2009, 6:42 pm

Hello John,

I have a scrap Solar which I'm breaking so send me a PM.

Howard

wireful3 · 22nd Jul 2009, 10:57 am

Howard , You have a PM.
It looks as if you might help me avoid a big disaster, though with the state of the bearing I doubt if anything could get worse.

Thanks for the suggestion.

Geoff 555 · 22nd Jul 2009, 9:08 pm

Hi, there are a few things I would try, very much as a last resort probably, large soldering iron or maybe a small gas torch, can of freezer and a length of bar. Short lengths ( 13" ) of silver steel bar can be got from model maker/steel suppliers and come in metric and imperial sizes, you need one to be a push fit down the bore of the tube, this is to stop the tube from collapsing , heat the bracket gently but be very careful, the tube is made out of Maszac (spelling 'sorry') or something like that which is cheap and noted for being a load of trouble, and freeze the bracket. See if you can get any movement, repeat and if you can get movement please come back and we will take it further.
Best of luck.
Cheers.
Geoff.

wireful3 · 23rd Jul 2009, 9:08 am

Hi Geoff,

I had not thought of using a rod down the centre to stabilise the casting so I will try this. Howard thinks he can let me have a spare part from a scrap set. If so I will be able to try very robust measures. It is so bad that I can hardly make things worse. The only concern is that the sleeve acts as a journal bearing for the AM tuning and in the present state is fine.

I too wondered how to spell "Mickey Mouse" alloy so didn't. It seems odd that it was used for in a set of this quality. I gather that it was also used for lots of other cast parts around that time so I wonder whether the weakness was not known then.
Regards

howard · 30th Jul 2009, 8:12 pm

Hello John,

My scrap Solar is being dismantled now, here's the tuning spindle and assembly, all in good order, but it looks different to the one above ?

If anyone needs Solar spares let me know ASAP.

Howard

wireful3 · 30th Jul 2009, 9:27 pm

Howard,
I think your picture is the whole assembly. Mine had been dismantled a bit further to show the outer bush where the serious damage occurred so I am sure what you pictured would be fine and solve my problem.

Everything else in the set seems in good order though the VHF tuning knob might have been damaged. How it broke the bush casting is a mystery to me.

Regards

wireful3 · 2nd Aug 2009, 8:11 pm

Just to tidy things up, the set is now tuning on both bands. Howard had a salvaged assembly that was an easy replacement so this meant that fortunately I could ignore the seized bush. The hardest task was re-stringing the drives and even this was not too bad, just fiddly.

I would like to thank everyone for their offers of advice, information and help especially Howard for the part.

Mods, this thread can now be closed please

Regards

21st Jul 2009, 12:09 pm	#1
wireful3 Retired Dormant Member Join Date: Sep 2003 Location: Bristol, UK. Posts: 808	Astrad Solar Tuning Knob Help needed I hope this is the right section it is more mechanics than circuit, if it is wrong Mods please move it. I have an Astrad Solar with the FM tuning seized. Tuning is two concentric knobs the inner one for AM and the outer for FM. The inner is fine and uses the FM shaft as a bearing for the mechanics. Looking at the mechanism I assume the FM shaft which is a tube with a shaped drum for the drive cord is intended to rotate freely also but it does not. The first question is am I right in this guess? If not it is a major mystery! It looks as if the thing has had rough time in the past. The part of the FM tube that the tuning knob presses on to is broken by the force of trying to turn it. I have dismantled things and the part in question is the front plate of the assembly. The tube goes through a hole in this plate and then the whole lot is supported with a top hat section to the rear. The outer tube for the FM tuning is so rigidly fixed in the front plate hole it seems as if it was shrunk fit. It looks like a casting of Mickey Mouse Metal that is now very brittle. I think I have heard that this is not very stable in size and can shrink. Could this have expanded? If I am right, I need to find a way of freeing the thing so that I can expand the hole a bit. Penetrating oil overnight had no effect but because of the fragile nature I have only used finger force to try to turn it. Can anyone suggest ways of freeing it? I will try to add a picture but my attempts in the past have been useless which is why I gave such a long description. Thanks in hope Attached Thumbnails

21st Jul 2009, 3:41 pm	#2
ekcobeach Rest in Peace Join Date: Mar 2005 Location: Wilmington, East Sussex, UK. Posts: 230	Re: Astrad Solar Tuning Knob Help needed Hi John, No help i'm afraid but i have two of these Astrads.One is perfect but the other has the exact same problem that you mention.I'm afraid i tried just about everything to unseize to damn thing but to no avail.In my frustration i resorted to a pair of Mole grips.Even they wouldn't budge it.I ended up chucking it in a box and bunging it in the shed. I hope someone comes up with something constructive for you.I'm past trying with mine.I'll watch this thread. Regards, Colin.

21st Jul 2009, 3:52 pm	#3
wireful3 Retired Dormant Member Join Date: Sep 2003 Location: Bristol, UK. Posts: 808	Re: Astrad Solar Tuning Knob Help needed Hi Colin, Thanks for the comment. It has helped, because you have confirmed I am trying to do the right thing. I will wait a while before getting frantic. It's amazing, I guess if they had intended to make a press fit bearing, it would have fallen out just by looking at it!

21st Jul 2009, 6:42 pm	#4
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: Astrad Solar Tuning Knob Help needed Hello John, I have a scrap Solar which I'm breaking so send me a PM. Howard

22nd Jul 2009, 10:57 am	#5
wireful3 Retired Dormant Member Join Date: Sep 2003 Location: Bristol, UK. Posts: 808	Re: Astrad Solar Tuning Knob Help needed Howard , You have a PM. It looks as if you might help me avoid a big disaster, though with the state of the bearing I doubt if anything could get worse. Thanks for the suggestion.

22nd Jul 2009, 9:08 pm	#6
Geoff 555 Heptode Join Date: Jan 2008 Location: Bristol, UK. Posts: 981	Re: Astrad Solar Tuning Knob Help needed Hi, there are a few things I would try, very much as a last resort probably, large soldering iron or maybe a small gas torch, can of freezer and a length of bar. Short lengths ( 13" ) of silver steel bar can be got from model maker/steel suppliers and come in metric and imperial sizes, you need one to be a push fit down the bore of the tube, this is to stop the tube from collapsing , heat the bracket gently but be very careful, the tube is made out of Maszac (spelling 'sorry') or something like that which is cheap and noted for being a load of trouble, and freeze the bracket. See if you can get any movement, repeat and if you can get movement please come back and we will take it further. Best of luck. Cheers. Geoff.

23rd Jul 2009, 9:08 am	#7
wireful3 Retired Dormant Member Join Date: Sep 2003 Location: Bristol, UK. Posts: 808	Re: Astrad Solar Tuning Knob Help needed Hi Geoff, I had not thought of using a rod down the centre to stabilise the casting so I will try this. Howard thinks he can let me have a spare part from a scrap set. If so I will be able to try very robust measures. It is so bad that I can hardly make things worse. The only concern is that the sleeve acts as a journal bearing for the AM tuning and in the present state is fine. I too wondered how to spell "Mickey Mouse" alloy so didn't. It seems odd that it was used for in a set of this quality. I gather that it was also used for lots of other cast parts around that time so I wonder whether the weakness was not known then. Regards

30th Jul 2009, 8:12 pm	#8
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: Astrad Solar Tuning Knob Help needed Hello John, My scrap Solar is being dismantled now, here's the tuning spindle and assembly, all in good order, but it looks different to the one above ? If anyone needs Solar spares let me know ASAP. Howard Attached Thumbnails

30th Jul 2009, 9:27 pm	#9
wireful3 Retired Dormant Member Join Date: Sep 2003 Location: Bristol, UK. Posts: 808	Re: Astrad Solar Tuning Knob Help needed Howard, I think your picture is the whole assembly. Mine had been dismantled a bit further to show the outer bush where the serious damage occurred so I am sure what you pictured would be fine and solve my problem. Everything else in the set seems in good order though the VHF tuning knob might have been damaged. How it broke the bush casting is a mystery to me. Regards

2nd Aug 2009, 8:11 pm	#10
wireful3 Retired Dormant Member Join Date: Sep 2003 Location: Bristol, UK. Posts: 808	Re: Astrad Solar Tuning Knob Help needed Just to tidy things up, the set is now tuning on both bands. Howard had a salvaged assembly that was an easy replacement so this meant that fortunately I could ignore the seized bush. The hardest task was re-stringing the drives and even this was not too bad, just fiddly. I would like to thank everyone for their offers of advice, information and help especially Howard for the part. Mods, this thread can now be closed please Regards