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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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25th Sep 2016, 10:41 pm | #1 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Murphy U472 VHF to 103MHz
I bought this for its extended VHF range and it was local. A bit tatty and dirty but looked to be all there apart from the Murphy nameplate. Inside was a replacement volume control and a melted wax capacitor but otherwise original. The output transformer was OK so I replaced all the Hunts and wax capacitors. Switched on whilst monitoring the HT and it came to life.
The speaker cloth was badly stained and dirty, tried cleaning to no effect, resorted to diluted toilet bleach which fixed it in no time and killed 99% of the germs. Near white speaker cloth is not such a bad thing after all. Left it running for a few hours and VHF deteriorated. A search on this site revealed the screen grid decoupler, disguised as a resistor, had been found responsible so tacked on a replacement and VHF was back. Amazing that 60 year old sets exhibit identical failure characteristics. Set about checking others of the same type and there are three 0.01uF used for RF suppression on the heater chain, two inside the VHF tuner. All were showing leakage so I replaced them, probably a bit of an overkill but better than diving for cover each time a crackle is heard on the radio. A final check and LW did not seem to do a lot. The aerial coil on the ferrite rod was o/c but it was the usual failure where it joins the tag so fiddly but simple fix. Back in the cabinet again and the radio is working fine. It is compact so the speaker is small and bass is a little light but its well built and most importantly goes that extra few MHz. |
26th Sep 2016, 9:37 pm | #2 |
Hexode
Join Date: May 2015
Location: Northampton, Northants, UK.
Posts: 380
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Re: Murphy U472 VHF to 103MHz
Cleaned up, it looks really handsome!
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28th Sep 2016, 12:50 am | #3 |
Nonode
Join Date: Jan 2008
Location: Milton Keynes, Bucks. UK.
Posts: 2,552
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Re: Murphy U472 VHF to 103MHz
An excellent job!
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When I die, please don't let my Wife sell my collection for the amount I told her I paid for it! |