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Old 26th Mar 2018, 11:37 pm   #1
Backtoreality
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Default Bush DAC 90

Hi all,
I've started working on a cream Bush DAC90 by replacing all the wax capacitors. Having searched on the site for information I came across members mentioning broken IFT slugs "clonking". Intrigued I rotated my chassis and was dismayed to hear a clonking from one of the IFT canisters. Has anyone documented the exact process of repairing these or could anyone who has done so share their experiences please. I don't want to destroy what could be a very nice radio at the end of the restoration.
Cheers,
David
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Old 26th Mar 2018, 11:48 pm   #2
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Default Re: Bush DAC 90

All I did with mine was to Araldite the broken bits together. three of the four slugs were broken. don't know if this is the ideal method, will the 'glue gaps' affect operation? All I can say is that after alignment the set performed outstandingly well, noticably better than the average 4+1 superhet.
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Old 27th Mar 2018, 10:58 am   #3
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Default Re: Bush DAC 90

Thanks for that.

I was hoping to avoid the re-alignment thing if at all possible, (never done it!) I do have the equipment to attempt re-alignment but I still remember my dad telling me it's the easiest way to kill a radio if you don't do it properly. He was talking about his Eddystone 659 which I still have 50 years later.
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Old 27th Mar 2018, 11:53 am   #4
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Default Re: Bush DAC 90

I too have glued together broken slugs of the type which are attached to a piece of threaded rod. I used Araldite Precision. It certainly works.

If the slug is "floating about" IF alignment will have been lost anyway. If only one slug is affected, simply adjust it for maximum output when receiving a weak off air signal.
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Old 27th Mar 2018, 2:12 pm   #5
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Default Re: Bush DAC 90

I used superglue. Suggestion: don't do anymore shaking until you've fixed this - ideally the slug will present a clean break and therefore should be easier to re-assemble and glue.
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Old 27th Mar 2018, 5:49 pm   #6
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Default Re: Bush DAC 90

I have had a few do this and found it difficult to get the brass rod and slug in line. Best to use a lathe or jig to line them up.
I have found that usually it is because the "twiddler" has been there and snapped them all because too much wax was used to lock the treads and it has run through and stuck the slug itself to the coil former.
Now before trying to move the adjuster I heat it upside down with a soldering iron to run the wax out not in.
I'm working on the idea of just removing one loose slug, putting a sliver of foam rubber or a brass spring between the slugs to hold them apart and on the brass rods and replacing the slug in the original position to avoid having to re-align. The brass spring, if I can find any, shouldn't alter the alignment.
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Old 27th Mar 2018, 6:08 pm   #7
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Default Re: Bush DAC 90

Brass will alter the alignment, it acts as negative ferrite/iron dust. Aligning a LW/MW set by ear isn't at all difficult if you can get something out of it in the first place.
 
Old 28th Mar 2018, 11:40 pm   #8
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Default Re: Bush DAC 90

Thanks for all the info. I will try over the weekend.

Regards, David
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Old 31st Mar 2018, 11:49 pm   #9
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Default Re: Bush DAC 90

Disaster!
I managed to remove the can from the second IF coils but I've had a disaster while trying to drill the brass rivets out of the top to be able to remove the broken slug. I could kick myself!!! The drill pushed the rivet out and I've managed to slice the sides off the top coil. I can't believe what I've done! T cap it all the slug won't come out yet, it looks like there are two tiny pieces of metal stopping it.
Seriously depressed,
David
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Old 2nd Apr 2018, 9:01 am   #10
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Default Re: Bush DAC 90

Any chance of a picture of the coil assembly , I /or someone may have a spare can all is not lost you will have it working again , I did a silly thing yesterday, this is how it went I must remove my thumb before the drill ahh to late drilled my thumb Mick.
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Old 3rd Apr 2018, 6:29 pm   #11
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Default Re: Bush DAC 90

It’s a long while since I restored a DAC90 but I don’t recall having to drill rivets out to get at the ferrite slugs. I may still have the set on my avatar which was a gutted 90 if you don’t get sorted.
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Old 3rd Apr 2018, 9:59 pm   #12
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Default Re: Bush DAC 90

A re-wind isn't that difficult. But try Dave Walsh at DAB Hand Radio [AKA 'Nutter on The Bus' hereat] ..... another good guy ..............
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Old 5th Apr 2018, 8:42 pm   #13
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Default Re: Bush DAC 90

Hi David

Just rooting through a box and found a couple of Bush IF coils from a scrapped PB83.

As far as I can see from the Manufacturers service data that the part numbers are the same.

you are welcome to them for the cost of postage if you want to give them a go

Cheers

Mike T
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