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Old 16th Jun 2013, 10:25 pm   #1
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Default Ekco AD65.

I'm currently restoring a "basket case" Ekco AD65. Fortunately the case is in reasonably good condition and I've managed to obtain a reproduction tuning scale.

So far I've restuffed the capacitor block, rewound two sections of the dropper resistor and replaced most components on the tag strip which the set seems to be built around.

However the set has been got at in the past. Several wires have been cut and capacitors of seemingly random values have been crudely soldered in in seemingly random places.

Of course I can work out the correct circuit wiring, but determining the correct commoning points is more difficult.

Is there an AD65 owner who can take some under chassis pictures for me please? Hopefully they will set me on the right track. I'm particularly interested in the wiring around C10 (Trader Sheet) which is mounted on the rear of the tuning capacitor.

Thanks.
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Old 17th Jun 2013, 6:56 pm   #2
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Default Re: Ekco AD65.

Hi,

I've just sent you a PM Graham as a friend of mine can possibly help you out. Good luck.

Kind regards, Col.
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Old 17th Jun 2013, 9:52 pm   #3
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Default Re: Ekco AD65.

Many thanks Col.

I'll have a look at your PM now.
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Old 18th Jun 2013, 5:41 pm   #4
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Default Re: Ekco AD65.

I am at about the same stage of repair as Graham. I understand there are at least two AD65 chassis versions with different valve line ups, My chassis had no valves and a few cut wires. I think a few close up photos would be a great help.
John.
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Old 19th Jun 2013, 2:08 pm   #5
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Default Re: Ekco AD65.

John.

I've emailed Retired's friend requesting some pictures. I'd be more than happy to forward them to you and/or post them here depending on file size.

My own AD65 has four valves. Later versions had five valves. Anything I can help you with please ask and I'll do my best to help.
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Old 19th Jun 2013, 5:09 pm   #6
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Default Re: Ekco AD65.

Hi Graham, Thank you for you offer of help. My set is also the four valve version.
John.
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Old 27th Jun 2013, 11:53 am   #7
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Default Re: Ekco AD65.

Pictures courtesy of Gary Tempest attached.
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Old 27th Jun 2013, 11:54 am   #8
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Default Re: Ekco AD65.

Three more.
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Old 28th Jun 2013, 9:52 pm   #9
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Default Re: Ekco AD65.

Thank you, Col, Gary and Graham. The pictures will be a great help when I get round to repairing my set.
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Old 29th Jun 2013, 4:35 pm   #10
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Default Re: Ekco AD65.

Good luck, these are neat radios. I too have the earlier 4 valve version. I like this version as the mains switch is separate and not part of the volume control. Mine was well restored when I bought it, including a new back panel, rewinding the dropper resistor and restuffing the caps.
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Old 17th Jul 2013, 7:05 pm   #11
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Default Re: Ekco AD65.

Work on this radio is progressing well. I'm about to replace the two 100NF capacitors in the mains filter. As these caps sit between mains and chassis, Y2 types are called for.

I have some Rifa PME 271 Y 100NF 300V~ types. However, in view of the criticism Rifa X type capacitors have come in for in these forums, I'm wondering if I dare fit them. What do members think?

If it's not a good idea, what alternative types are best? The fact these capacitors are 100NF rather restricts the choice. My understanding is that Kemet types are made by Rifa, or perhaps it's the other way round? The only other type I've seen is Epcos.

I must admit that in the past I'd just have fitted yellow polypropylene types with a suitable voltage rating.
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Old 17th Jul 2013, 8:56 pm   #12
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Default Re: Ekco AD65.

I would say 100nF is pushing it a bit for a Y capacitor installation- that's nearly 7.5mA of earth leakage current- enough for a bit of a bite if the earth comes off! 10nF would be "better" I reckon and certainly easier to source.

It's not obvious where they actually go to from the circuit- an earth connection is shown (rather than chassis which goes to one side of the mains). Is there an earth socket which is only connected to this centre point of the capacitors? There's only a two pole mains entry.
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Old 18th Jul 2013, 11:14 am   #13
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Default Re: Ekco AD65.

Visual inspection of the chassis shows that the centre point of the capacitors is wired to a SIGNAL earth terminal which is insulated from the chassis. This is quite clear on the Trader sheet, but less clear on the manufacturer's sheet.

So with no earth connected and all things being equal there will be about 120VAC across each cap. With a good earth connected there will be full mains voltage across one cap and a low voltage across the other.

I take your point about leakage current. I'll pick up a couple of 10NF Y2 caps from Maplin. They're made by Wima and being physically smaller than the 100NF types will be easier to fit.
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Old 6th Aug 2013, 9:14 pm   #14
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Default Re: Ekco AD65.

An update on progress so far.

Cleaned the chassis using kitchen roll and cotton bubs moistened in water. Stubborn grease and wax spots were removed using white spirit. The chassis showed some signs of rust, but not enough to justify repainting it.

The resistance wire on two sections of the dropper resistor had come unravelled. The sections were carefully rewound and the ends reterminated using high melting point solder.

Replaced the capacitors in the mains filter with class Y2 types.

Several "modern" electrolytic cpacitors which had been soldered directly to valveholders etc. were removed.

The smoothing capacitor block and two cardboard cased electrolytic capacitors were restuffed. A helpful forum member produced artwork for the labels for the restuffed tubular types.

All the components on the "tag strip" were replaced with the exception of the flat wirewound resistor, which tested OK. The set is built around this tag strip and I do not want to have to revisit it in the future.

All waxed paper dielectric capacitors were replaced along with all out of spec resistors.

Reterminated or replaced the wiring to the mains switch, mains filter, rectifier, dropper resistor, speaker energising coil and output transformer.

Carefully checked the wiring, accounting for every wire on every tag.

Measured the resistance between various tags and compared the readings with the expected values.

Checked the scale illumination lamp for continuity.

Reattached one of the valve cap sockets which had become become detached from its wire.

Cleaned the tarnish off all the valve pins and valve holder sockets using Servisiol. Some valve holder sockets were "nipped up" as they did not grip the valve pins very well.

Gave the wave change switch a squirt of Servisol and worked it to and fro a few times.

Stuck the valve cap back on to the output valve using Araldite Precision Adhesive. There was enough wire protruding from the top of the valve to allow it to be resoldered.

Tested the valves on my AVO CT160. All were OK apart from the VP1321 which showed low emmission.

At this stage I felt confident enough to apply the full mains voltage. Lacking the correct power connector, I just soldered the mains lead conductors directly to the pins on the back of the set. Six feet of old mains conductor was used as an aerial. I did not connect a signal earth.

I was amazed that the set worked first time. A full complement of English, French and German stations on Long Wave, but BBC R4 was at a lower volume than the other stations. Classic Gold and BBC R5 Live received at good volume on Medium Wave.

I checked voltages and compared them with the service sheet. All were OK except for the screen grid of the VP1321. This should vary between 115V and 145V depending on the setting of the volume control. It actually measured 145V to 200V. I've put this down to the low emission of the VP1321 and will attempt to source a new one.

There are three problems to sort before I realign the set:-

1. There is a Paxolin?? lug on the wavechange switch wafer which is meant to constrain its rotation. However it is worn and over-rides one of the stops allowing rotation through about 300 degrees. Careful bending of the stop has failed to cure the problem. I'll try extending the stop by soldering a piece of brass to it. Alternatively I may be able to glue a new lug to the wafer.

2. There is a crackling sound from the speaker at the same position of the tuning capacitor on both wavebands. This occurs when the cap is almost fully meshed. I put this down to bent vanes, or debris between the vanes. Unfortunately careful examination under a magnifier has failed to reveal anything.

3. There is a bracket which runs across the face of the speaker and supports the pivot for the illuminated dial pointer. This is either deliberately "dished" by design, or has been accidently bent at some time in the past. Can anyone advise whether this bracket should be straight or dished? Thanks.
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Old 6th Aug 2013, 10:17 pm   #15
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Default Re: Ekco AD65.

Hi Graham, You make it sound so easy, well done I hope my set works first time but I very much doubt it. VP1321 seem to be very rare now. After trying without luck I have had to get a replacement valve, but I will have to swap the Anode lead and grid lead.
John.

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Old 10th Aug 2013, 3:43 pm   #16
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Default Re: Ekco AD65.

Ref 3. above. One side of bracket is slightly forward and the other side is slightly back on my set but it has been dropped and the top fixing points are missing. I think the bracket should be straight in respect of the main chassis. Just need someone with a set that has not been dropped to verify my findings.
It would also help if someone could measure length of the top two Bakelite supports.
John.
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Old 10th Aug 2013, 8:42 pm   #17
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Default Re: Ekco AD65.

Thanks John.

I'll try my chassis in the cabinet and see how close the pointer is to the tuning scale. That should give me an idea as to whether the supporting bar is meant to be straight or bent.

While I'm at it I'll take the measurements you require.
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Old 11th Aug 2013, 1:52 pm   #18
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Default Re: Ekco AD65.

John.

I hope I'm answering the correct question. If not you'll need to clarify things.

The top supports thread into 2 BA threaded inserts moulded into the Bakelite. As you can see from the pictures, one of the inserts in my set has broken off, so I'll be reaching for the super glue.

The actual fixing is made from 10mm Across Flats (AF) brass threaded 2 BA at each end.

The end which screws into the insert is 4.5mm long.
The hex section is 7mm long.
The end on which the nut screws is 10mm long.

If your set is missing the fixings I'd be happy to make some for you.

I have the additional problem that one of the inserts for the lower chassis fixing screws is missing along with a chunk of Bakelite.

I'll probably start a new thread regarding the cabinet repair.
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Old 11th Aug 2013, 1:57 pm   #19
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Default Re: Ekco AD65.

Regarding the cross bar (part of the speaker mounting plate) which supports the pivot for the scale pointer, it's obvious that the bar in my set has been accidently bent. So much so that the pointer contacts the speaker surround at one end and misses it by 10mm at the other.

I daren't straighten the bar in situ for fear of damaging the speaker cone, so I'll have to remove the speaker mounting plate from the set. I should then be able to determine whether any "dishing" of the bar is needed.
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Old 11th Aug 2013, 3:13 pm   #20
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Default Re: Ekco AD65.

Quote:
I'll probably start a new thread...
Super pun!
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