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 > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Closed Thread
 
Thread Tools
Old 28th Feb 2023, 3:01 pm   #1
Dorian27
Heptode
 
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 564
Default Ekco U428

This radio works OK for 20 minits or so then the sound becomes distorted as if they are taking through water or bubbles I have tested all valves and they all test good. Nothing else has been touched. I don't know where or what might be causing this. Has any one got any ideas what I should be looking for please
Dorian27 is offline  
Old 28th Feb 2023, 3:15 pm   #2
Nuvistor
Dekatron
 
Nuvistor's Avatar
 
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
Posts: 9,427
Default Re: Ekco U428

Check the grid coupling capacitor and bias components on the UL84 output valve. The UL84 could also be drawing grid current after 20 mins and could be faulty.
__________________
Frank
Nuvistor is online now  
Old 28th Feb 2023, 3:21 pm   #3
chompy1
Hexode
 
Join Date: Oct 2010
Location: Launceston, Cornwall, UK.
Posts: 292
Default Re: Ekco U428

does the radio have any wax coated capacitors? If so, they probably need replacing
chompy1 is offline  
Old 28th Feb 2023, 4:53 pm   #4
Dorian27
Heptode
 
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 564
Default Re: Ekco U428

Do you know what part no is the grid coupling capacitor on the manufacturer service sheet please. And no there are no wax capacitor or Hunts.
Dorian27 is offline  
Old 28th Feb 2023, 5:19 pm   #5
chompy1
Hexode
 
Join Date: Oct 2010
Location: Launceston, Cornwall, UK.
Posts: 292
Default Re: Ekco U428

the Pye 1107 uses the same chassis and I have a Pye 1107 which had the same problem as your Ekco. Try replacing C65 which has a value of 0.01uf.

Paul
chompy1 is offline  
Old 28th Feb 2023, 5:36 pm   #6
chompy1
Hexode
 
Join Date: Oct 2010
Location: Launceston, Cornwall, UK.
Posts: 292
Default Re: Ekco U428

C65 is right next to R36
chompy1 is offline  
Old 28th Feb 2023, 6:13 pm   #7
dazzlevision
Dekatron
 
Join Date: Sep 2003
Location: Near Swindon, North Wiltshire, UK.
Posts: 3,595
Default Re: Ekco U428

You might find this post helpful: https://www.vintage-radio.net/forum/....php?p=1497567
dazzlevision is offline  
Old 28th Feb 2023, 6:30 pm   #8
chompy1
Hexode
 
Join Date: Oct 2010
Location: Launceston, Cornwall, UK.
Posts: 292
Default Re: Ekco U428

C60 (2uf) probably needs replacing and the mains smoothing capacitors are probably past their best too
chompy1 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 12:45 am.


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 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.