UK Vintage Radio Repair and Restoration Discussion Forum

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-   -   Murphy U472 (https://www.vintage-radio.net/forum/showthread.php?t=160282)

Pete_kaye 4th Oct 2019 6:12 pm

Murphy U472
 
I have just started looking at this .I will need a pair of 50 UF electrolytics . What/ where should I get them. Is 450v dc adequate 105C ?

Nuvistor 4th Oct 2019 6:31 pm

Re: Murphy u472
 
450 Vdc is fine, These are 500V D.C. but anything over 350vdc would be fine.

https://www.cricklewoodelectronics.c...Capacitor.html

There are other suppliers, check this post .
https://www.vintage-radio.net/forum/...d.php?t=160219

Pete_kaye 5th Oct 2019 1:19 pm

Re: Murphy U472
 
Can anyone sell me two?

Nuvistor 5th Oct 2019 7:49 pm

Re: Murphy U472
 
If it’s to replace c63 and c64 the one from cricklewood is a dual 50+50 500 vdc.
Are you looking for two to stuff the original can?

PJL 7th Oct 2019 11:03 pm

Re: Murphy U472
 
Electrolytics of this age are generally pretty reliable although it is best to apply power gently to reform them. Don't think I replaced the one in my U472.

Pete_kaye 8th Oct 2019 5:49 pm

Re: Murphy U472
 
Well ,the red terminal gave 72 UF and 1.8R but the other side gave ' Diode , Vf =...'. There was a loud noise so I switched off. I was on a limiter.
I am planning to restuff.

Nuvistor 8th Oct 2019 6:07 pm

Re: Murphy U472
 
I donít have any but Cricklewood have these, probably CPC, RS and Farnell have similar ones.

https://www.cricklewoodelectronics.com/47H450.html

Was the loud noise from the smoothing can? They can explode and when they do they usually spay silver foil over the chassis, you donít want to be too near if the fail.

Pete_kaye 8th Oct 2019 6:11 pm

Re: Murphy U472
 
I forgot to say that there was a hole leaking stuff near one terminal!

Pete_kaye 22nd Oct 2019 2:30 pm

Re: Murphy U472
 
1 Attachment(s)
I got some 50 uF caps very cheaply via China and they just arrived . I have fitted this new part across the rectifier to replace an old waxy but is it adequate as the Murphy notes say '1000 Vdc' ?

westcliff 22nd Oct 2019 7:45 pm

Re: Murphy U472
 
That one's okay as it is an X2 type and marked for 250V AC.

Gus.

Pete_kaye 25th Oct 2019 1:09 pm

Re: Murphy U472
 
Thanks .It is now working well on Mw and LW with 2 new caps . However, there is just a high pitched squeal on VHF , with or without aerial. There is a hint of station at several points. The UCC85 valve is tested. Where to now?

Pete_kaye 3rd Nov 2019 12:25 pm

Re: Murphy U472
 
Sorted . As advised , I changed C23 and VHF came on . Subbing a better UCC85 gave all stations across the band; the previous one did not. It is now back in the case and working well- thanks to this site.:)


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