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Success Stories If you have successfully repaired or restored a piece of equipment, why not write up what you did and post details here. Particularly if it was interesting, unusual or challenging. PLEASE DO NOT POST REQUESTS FOR HELP HERE!

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Old 25th Aug 2016, 10:26 pm   #1
cosmocat
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Default Murphy U198H and the impossible wave change lever.

I was given this cute Murphy 198H as a present from a friend who knows I love to tinker.
The radio responded well with the usual re-capping of the electrolytics and waxies and a good dose of switch cleaner.
An initial power up showed a healthy HT but no sound at all from the speaker. A few more tests showed the voice coil was open circuit. As the cone was also ripped I decided a new speaker was the only sensible way forward. A new speaker fitted and the radio was back in working order.
A howl when tuning was cured by fitting a new mixer/osc valve.

Now the bad bit, these radios have the wave change switch on the back, operated by a lever that pokes out the side. This lever was broken and a little research suggested that this is very common and good levers are very hard to find.

I mentioned my plight to another friend and he said he could probably print a new one with his 3D printer! I gave him the part of the broken lever I had and a few measurements taken from the case. He modelled the lever in a CAD package and 20mins later the new lever was completed on the printer.

A trial fitting on the radio and it fitted well and looked just right.
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Old 26th Aug 2016, 10:55 pm   #2
Phil G4SPZ
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Default Re: Murphy U198H and the impossible wave change lever.

Absolutely brilliant! I love it when 21st century technology is used to repair something seventy years old. I wonder if 3D printers can create other hard-to-find parts, such as knobs? No reason why not. Well done!
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Old 27th Aug 2016, 4:55 pm   #3
Refugee
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Default Re: Murphy U198H and the impossible wave change lever.

That wave change leaver looks like it was made using quite an expensive 3D printer.

They vary greatly in print quality from making a part up out of blobs of hot melt glue right the way through to 3D laser printing with engineering accuracy.
Perhaps a new thread could be started if someone is interested enough.
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Old 28th Aug 2016, 1:56 pm   #4
dave walsh
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Default Re: Murphy U198H and the impossible wave change lever.

It's impressive. I recall mentioning 3D printing a few years back and some people asking if it was a joke [I had thought that myself originally] but it was quickly being seen as ideal for this sort of usage rather than machining parts or using resin in moulds [I don't have those skills but printing doesn't require them]. At that stage 3DP was being pitched widely as part of a new economic structure where parts would be printed in the home [the example was a new Lawnmower Handle]. Of course this model assumed the customer would [a] want to do this [b] had the to fit the replacemen-diminishing these days! It's hard to predict the future Ideal for vintage restoration though. Maybe someone with access to a high quality machine could offer a service on a "paid for" basis? Just a thought.

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Old 28th Aug 2016, 5:16 pm   #5
Julesomega
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Default Re: Murphy U198H and the impossible wave change lever.

Someone on the Yahoo FRG-7 group asked recently for dimensions of the main tuning knob, so I posted detailed drawings which he turned into a .stl file and printed a very convincing replacement.
That Group requires membership to read the posts, but I attach his photo of the completed job
https://groups.yahoo.com/neo/groups/FRG-7/
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Old 29th Aug 2016, 12:08 pm   #6
Stuart R
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Default Re: Murphy U198H and the impossible wave change lever.

I passed this shop front in Clerkenwell, London a few months ago. They offer a range of printers for sale and training courses as well as on-demand object scanning and printing services. If you can't provide an error-free CAD file, the object scanning looks like it could double the cost of a completed one-off job.

https://www.imakr.com/en/content/128-urbanmanufacturing

No connection with them, but this thread jogged my memory and it seemed useful to mention them here.

Surely, there must be other companies offering similar services elsewhere in the UK.

SR
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