UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Success Stories

Notices

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!

Reply
 
Thread Tools
Old 20th Feb 2021, 12:28 am   #1
Nanozeugma
Hexode
 
Nanozeugma's Avatar
 
Join Date: Nov 2017
Location: London, UK. Manchester once a month :)
Posts: 442
Default Murphy U198H.

A fairly basic, small ac/dc superhet in a one piece purpl(ish) moulded cabinet from 1954 which cost about £10 when released.
One unusual feature being that it is fitted with a ferrite rod aerial, possibly among the first.

This little set was actually given to me, and sat on the round tuit pile for some time as it didn't appear to be of particular interest, and I'm not especially fond of live chassis sets at any time.

It is a rather basic set in a small moulded cabinet which I initially thought was bakelite, but given the distinct lack of success with Greygate polish on the dull top of the cabinet, I'm inclined to think it is another form of early plastic.

The small size of the cabinet means there is no room on the fascia for a waveband switch, this being relegated to the back of the chassis operated by a lever.

Similarly, the "tone control" is a two position slider switch, also on the back of the chassis.

It's neat little five valve design, using U series Mazda valves and a vertically mounted mains dropper. On opening it up, there was virtually no sign of rust (except a tiny bit on the top edge of the loudspeaker basket), the chassis being coated with a crackle finish grey paint which has survived well.
The chassis was initially reluctant to release it's grip on the cabinet, being held by two channels moulded into the cabinet sides.
The 1.25 inch 250mA ht fuse was missing.
Cold meter readings revealed no unpleasant shorts, the heater chain had continuity as did all sections of the mains dropper.
The audio output transformer has a hum buck tap on the primary and all windings fortunately read intact.
Due to the small design, the op tx is bolted to the speaker basket.
The twin can reservoir / smoothing electrolytic showed no signs of venting or other distress.
All the wax / Mouldseal Hunts capacitors were replaced, each original tested on removal showing significant leakage as might be suspected.
Some required a fair degree on dexterity and dismantling to access and replace as the design is so small.
A moment of injudicious vigorous desoldering under the UL41 valve socket meant I managed to snap a pin off. Fortunately I was able to extract the remains from the McMurdo socket and fit a replacement pin.
The twin pole on/off switch was sound but much to my surprise I found an open circuit live conductor in the mains cable. This was two core vinyl of the period using then standard British colours of red/black.
The cable bore no visible signs of distress or kinks, but the red was most definitely o/c.
I replaced the cable, but curiosity got the better of me as to where the break was in the original... not near the strain relief at the chassis, nor where it had been secured in a plug, but about a foot up the cable, very odd.

I checked my work and applied power initially using an isolation transformer and a variac, gradually winding up the AC to full mains. As the HT hit 175v, the set burst into life; alignment followed, not much off beam.
I left it on Five Live for a bit and pronounced it fit.
Quite an amusing little set.
Attached Thumbnails
Click image for larger version

Name:	front_small.jpg
Views:	149
Size:	83.8 KB
ID:	227152   Click image for larger version

Name:	back_small.jpg
Views:	150
Size:	93.5 KB
ID:	227153   Click image for larger version

Name:	chassis_small.jpg
Views:	150
Size:	107.8 KB
ID:	227154  
__________________
Thermionic Emission, cures depression, boredom and piles.
Nanozeugma is offline   Reply With Quote
Old 20th Feb 2021, 4:20 am   #2
AmateurRepairer
Pentode
 
AmateurRepairer's Avatar
 
Join Date: Dec 2020
Location: Chesterfield, Derbyshire, UK.
Posts: 138
Default Re: Murphy U198H.

Nice one I have a M version I’m changing the hunts and all the waxies. Just got to sort out the sound transformer.
__________________
Working on a Murphy U198M, Marconi CR100, PYE VHF2D x2, P75A and 25C.
AmateurRepairer is offline   Reply With Quote
Old 2nd Mar 2021, 3:11 pm   #3
vinrads
Nonode
 
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 2,793
Default Re: Murphy U198H.

Hi no name !sorry , I nice write up on restoring the set looks a clean chassis and now good for quite a few years use now , Mick.
vinrads is offline   Reply With Quote
Old 2nd Mar 2021, 3:17 pm   #4
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 21,506
Default Re: Murphy U198H.

They are good performers. There was also a wooden cabinet variant using the same chassis, the U598.
paulsherwin is online now   Reply With Quote
Old 2nd Mar 2021, 8:10 pm   #5
stitch1
Heptode
 
stitch1's Avatar
 
Join Date: Jan 2008
Location: Durham, County Durham, UK.
Posts: 657
Default Re: Murphy U198H.

Good job

There seems to be quite a few around and they’re quite popular.

I have a woody version, last time I looked the case had completely collapsed but I do have all the parts except the lever on the back.

I didn’t realise it has a ferrite rod under the chassis.

John
Attached Thumbnails
Click image for larger version

Name:	EE1845EF-59AF-4687-A57F-70F7F24A87E5.jpg
Views:	65
Size:	135.6 KB
ID:	228111  
stitch1 is offline   Reply With Quote
Old 2nd Mar 2021, 9:33 pm   #6
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 21,506
Default Re: Murphy U198H.

It's an odd place to put a ferrite rod. You'd think that the chassis would screen it, but in fact it works perfectly well.
paulsherwin is online now   Reply With Quote
Old 2nd Mar 2021, 11:19 pm   #7
Restoration73
Nonode
 
Restoration73's Avatar
 
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,186
Default Re: Murphy U198H.

Cleaning the valve pins and sockets may improve matters. I had to tweak the MW aerial
trimmer, and after carefully restringing the drive cord tuning is smooth and dial
calibration is spot on.

I prefer this to a DAC90A !
Restoration73 is offline   Reply With Quote
Old 3rd Mar 2021, 7:51 am   #8
Beardyman
Hexode
 
Beardyman's Avatar
 
Join Date: Jan 2018
Location: Portsmouth, Hampshire, UK.
Posts: 312
Default Re: Murphy U198H.

My other half has one of these in her workroom at home, its on all day every day! Solid little sets & they do sound good. Once fettled they'll carry on for years. Well done on the restoration, good write up too. Big thumbs up from me!
__________________
The difference between stupidity and genius is that genius has its limits. (Einstein)
Beardyman is offline   Reply With Quote
Old 25th Mar 2021, 2:16 pm   #9
telstar
Octode
 
Join Date: Dec 2003
Location: Leeds, West Yorkshire, UK.
Posts: 1,254
Default Re: Murphy U198H.

Hi. Quite an interesting restoration, well done. I have one of these radios (not sure if it is "H" or "M"). Mine is dead at present, so perhaps the mains live wire is o/c?
I bought mine from a shop (Adams Audio) on Spring Road in Ipswich, Suffolk many years ago. This road once contained a "treasure trove" of second hand shops which yielded many vintage radios, sadly now all gone.
Cheers
Mike
telstar is offline   Reply With Quote
Old 30th Mar 2021, 8:48 am   #10
Hybrid tellies
Nonode
 
Hybrid tellies's Avatar
 
Join Date: Jan 2004
Location: Bristol, UK
Posts: 2,548
Default Re: Murphy U198H.

A nice write up, thank you. These little compact 1950's valved AC/DC radios can give a good account of themselves.
__________________
Simon
BVWS member
Hybrid tellies is offline   Reply With Quote
Old 1st Apr 2021, 11:03 am   #11
McMurdo
Dekatron
 
McMurdo's Avatar
 
Join Date: Jun 2009
Location: Staffordshire Moorlands, UK.
Posts: 4,291
Default Re: Murphy U198H.

Nice report, I always understood that Murphy aimed these to compete at the lower end of the market, so it's good to hear they give a decent account of themselves. I like the dropper heatshield, I'm sure some designers wouldn't have bothered!
__________________
Kevin
McMurdo is offline   Reply With Quote
Old 1st Apr 2021, 11:10 am   #12
paulsherwin
Moderator
 
paulsherwin's Avatar
 
Join Date: Jun 2003
Location: Oxford, UK
Posts: 21,506
Default Re: Murphy U198H.

Like most small 1950s MW/LW radios, they were designed to appeal to the emerging 'second set' market as people bought radios for kitchens and bedrooms, after TVs started to dominate the lounge. Many of them were semi-portable.
paulsherwin is online now   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 4:38 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.