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 5th Jul 2022, 11:31 am   #41
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Metal dial scale arch now sprayed Ford Rio Brown and fitted to dial scale. I am presently unable to fit it to the set as I need to replace the volume pot, a procedure that would be greatly impeded by the dial scale being in place.
Attached Thumbnails
Click image for larger version

Name:	20220705_111803.jpg
Views:	144
Size:	98.5 KB
ID:	260439  
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 11th Jul 2022, 8:36 pm   #42
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

I've now fitted the new volume pot with combined on/off switch, it was a special low profile one in order to fit into the narrow gap provided. And I've re-assembled the chassis with the rebuilt frame aerial and anything else that was previously dismantled or un-wired. At switch on I was rewarded with no sound. A look around the Trader sheet showed a speaker switch. Looking at its location fitted to the inside of the back panel it comprises two brass contacts that are 'made' when a brass pin with plastic knob is screwed into a hole to electrically link the contacts. It was missing. Fitting one rewarded me with a slight hum when the volume pot is up full (as to be expected), but that's about all. This was done in the dying embers of my time in the workshop so I'll go in with the voltmeter tomorrow. For the record, adjusting the tuner, wave change switch or anything else for that matter has no audible effect on what is coming out of the speaker, no clicks, pops or changes in tone, just the aforementioned low hum that can be raised and lowered by the volume pot - again as you'd expect. A finger on a screwdriver inserted into the gram socket produces rude noises, so it would appear that the output stage is working ok. So, back at it tomorrow.
Attached Thumbnails
Click image for larger version

Name:	20220711_200649.jpg
Views:	159
Size:	83.0 KB
ID:	260797   Click image for larger version

Name:	20220711_200727.jpg
Views:	166
Size:	97.2 KB
ID:	260798  
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 12th Jul 2022, 8:21 pm   #43
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Fault found but not fixed! I was getting zero volts on the anode of V1. Checking voltages it became clear that HT was reaching L4 (inside a tuning transformer can) but there was nothing on the wire coming out of the can going to V1's anode. Anyway, it's not an easy job to get inside the can as anyone who has done this will know, lots of awkward unsoldering and even cutting of wires to enable the can and contents to be removed. The coil former is a relatively crude turned wood affair and contains the aforementioned L4 plus L5, L6 and L7. I actually found a break in the fine wire leading to L4 from the solder post and re-soldered it - see second photo. But the end to end discontinuity still existed. The break is within L4 as I can read the resistance of L5. In the past I have managed to repair a broken wire in a tuning can, but this time the break is not 'accessible', it is buried underneath another coil and will need to be rewound by a professional.

As an aside and a further complication, the Trader sheet appears to be in error. The wire going to the broken coil is from the HT line and this coil is shown on the Trader sheet schematic as L4. However, taking resistances of L6 and L7 into account (2.2 and 28 ohms respectively), 'L4' sits actually underneath a 28 ohm winding - L7 in the component list. Yet on the circuit diagram L4 is mutually coupled to L6!
Attached Thumbnails
Click image for larger version

Name:	20220712_191729.jpg
Views:	108
Size:	61.1 KB
ID:	260832   Click image for larger version

Name:	20220712_183252.jpg
Views:	108
Size:	114.2 KB
ID:	260833  
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Jul 2022, 4:55 pm   #44
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

The tuning transformer has gone off to be rewound, so not a lot more I can do on this set until that is back and refitted. Oddly enough, given the condition of the chassis, the case is in truly excellent, polished condition. It suggests that the set was once owned and looked after but for some reason was put away in a shed maybe with a gap in the door or window such that that one side of the chassis was badly corroded and covered in mould as a result of weathering.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 29th Jul 2022, 8:28 pm   #45
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Mike Barker has completed the rewind of the tuning transformer and it's on its way back to me, so I'll be working on the set again soon.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 13th Aug 2022, 7:51 pm   #46
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

I am now in possession of the rewound tuning transformer courtesy of Mike Barker and am in the process of refitting it. It's proving to be quite a difficult task because there are connections to be made inside the transformer's screening can and more outside of it including two top caps, one of which is shielded. The problem being it's all so very tight to access (above and below the chassis) and the inherent problem of trying to resolder relatively short wires with the can in the way. Not to mention working with screened cotton wires where the screening is opened up to allow the cut ends of the signal wire within to go to separate places but leaving the screen intact and common to both wires. I think I'm winning so far but I'm afraid my vocabulary has temporarily expanded somewhat.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 14th Aug 2022, 3:25 pm   #47
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

And there's me thinking that after refitting the rewound coil everything would be fine.. Well, yet another 'coil in a can' is open circuit! There was no volts on the anode of V3, yet there was HT going into the can, but nothing coming out - just as the last time with V1. Anyway, after lots of desoldering of dirty grimy, hard to get at solder joints on the underside of the can, and cutting the braided wire from the top, I was able to remove the can and get inside it. This time however the break in the coil is between where the coil ends (or starts) and joins the outgoing terminal - it's accessible. I haven't tried rejoining it yet as after all that lot, I've had enough and having done this kind of thing before, joining fine wires, I want to be on the ball and calm. Photos soon. Bad luck or what?!
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 14th Aug 2022, 7:32 pm   #48
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Photos re previous post. The first two show the underside of the chassis. The brown, dogbone shape being the underside of the tuning can in question. As you can see there are numerous awkward to get at connections to it, and 'floating' components in the way that also had to be unsoldered and folded back in order to gain access. After successfully disconnecting all of these components and undoing its captive nuts I was then able to access the inside of the can. The final photo shows a close up of the coil in question in the bottom-middle of the photo. To the left is the wispy, broken wire that needs to be carefully lengthened and connected to the top RH terminal. It's all doable.
Attached Thumbnails
Click image for larger version

Name:	20220814_142129.jpg
Views:	102
Size:	80.8 KB
ID:	262790   Click image for larger version

Name:	20220814_142056.jpg
Views:	97
Size:	121.1 KB
ID:	262791   Click image for larger version

Name:	20220814_151555.jpg
Views:	98
Size:	62.4 KB
ID:	262792  
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 8:19 am   #49
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Out of interest, during fault finding I noticed that at switch on the HT rises to just under 500v before settling down to around 230v. I'm wondering if that temporarily high HT could cause these fine coils to blow, especially if (prior to me replacing them) there were very leaky caps that could provide a DC path to ground?
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 9:19 am   #50
vinrads
Dekatron
 
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,706
Default Re: Ekco ACT96 restoration

Hi Steve bad luck as you say but I suppose it was to be expected with the state of the chassis damp and all, keep at it . Mick.
vinrads is offline   Reply With Quote
Old 15th Aug 2022, 11:11 am   #51
cathoderay57
Nonode
 
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,338
Default Re: Ekco ACT96 restoration

Quote:
at switch on the HT rises to just under 500v before settling down to around 230v
Usually that only happens when a directly heated rectifier is fitted. I couldn't make out from the image in Post #42 what you've got in there. The original valve was supposed to be an IW3 which is indirectly heated. If you have a directly heated valve then swapping it for an indirectly heated might mitigate the problem. You've probably already seen the warning in the Ekco service sheet saying a directly heated valve shouldn't be used. Some sets get around the problem by using a bleed resistor between HT and chassis but since one wasn't originally specified it would be a bad idea to fit one to this set since it would increase the HT load. If the AF output valve has a slow warm-up that can also exacerbate the problem. Jerry
cathoderay57 is offline   Reply With Quote
Old 15th Aug 2022, 12:58 pm   #52
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Thanks Jerry, I'll check what rectifier is fitted.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 2:03 pm   #53
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

The rectifier fitted is a Mullard IW4/350, an indirectly heated rectifier - that should be fine shouldn't it? Otherwise what could be causing the initial HT level of 500V, or maybe that's how it should be?
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 2:15 pm   #54
cathoderay57
Nonode
 
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,338
Default Re: Ekco ACT96 restoration

Quote:
The rectifier fitted is a Mullard IW4/350, an indirectly heated rectifier - that should be fine shouldn't it?
Yes. As I said in Post #51, if the AF output valve has a slow warm-up that could cause it. I can't think of any other reason. Presume you've checked that your HT capacitors can handle 500v surge? Jerry
cathoderay57 is offline   Reply With Quote
Old 15th Aug 2022, 3:04 pm   #55
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Quote:
Originally Posted by cathoderay57 View Post
Quote:
The rectifier fitted is a Mullard IW4/350, an indirectly heated rectifier - that should be fine shouldn't it?
Yes. As I said in Post #51, if the AF output valve has a slow warm-up that could cause it. I can't think of any other reason. Presume you've checked that your HT capacitors can handle 500v surge? Jerry
Fortunately yes they will, they're BVWS 500V ones. Saying that, it's a chicken and egg situation, they shouldn't have to handle 500V if there's a 'fault' causing the initial high voltage. I don't know if the AF output has a slow warm up? I've got the correct valves fitted. Maybe when I cure this latest fault the loading on the HT will be greater and the HT won't rise so much initially. Cheers.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 4:51 pm   #56
cathoderay57
Nonode
 
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,338
Default Re: Ekco ACT96 restoration

It's basically a horserace between the warm-up of the rectifier and the output valve, which is the biggest HT current sink. Maybe the IW3 had a slower warm-up time than the IW4/350. I note that the former draws a heater current of 2.4A whereas the latter only 2.0A although to what extent that would affect the warm-up time I'm not sure. The additional HT load from the other valves will help but only marginally. Since your caps are surge rated high enough it is probably not worth worrying about. Cheers, Jerry.
cathoderay57 is offline   Reply With Quote
Old 15th Aug 2022, 5:51 pm   #57
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Thanks Jerry. I'd fit an IW3 if I could get one! or a UU3. Actually, just looked, the National Valve Museum states that the IW4/350 is a replacement for a UU3. Saying that, we know that 'replacement' valves are not necessarily exact equivalents. They'll work in many cases but in some they will throw up a gremlin.
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 5:59 pm   #58
cathoderay57
Nonode
 
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,338
Default Re: Ekco ACT96 restoration

One last thought - check that the heater pins and sockets of the Pen4VA are nice and clean. With a 1.4A heater at 4v it doesn't take many Ohms resistance to drop the voltage and slow down the valve's warm-up time. Cheers, Jerry
cathoderay57 is offline   Reply With Quote
Old 15th Aug 2022, 6:32 pm   #59
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

Thanks Jerry!
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Old 15th Aug 2022, 6:36 pm   #60
stevehertz
Dekatron
 
stevehertz's Avatar
 
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,789
Default Re: Ekco ACT96 restoration

I don't know wether to scream or cry. I managed to use a length of very fine AM 'ferrite rod' aerial wire to rejoin the broken coil and fix it down using melted wax - pukka job. Measured it and - as it should - it reads 80 ohms. So, all set to put the coil and its can back together and replace it into the chassis, re-wire everything up etc. I thought I'd just better check the other coil in the can first.. it's open circuit..
__________________
A digital radio is the latest thing, but a vintage wireless is forever..
stevehertz is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 8:05 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 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.