Ekco A222 Resistor Query - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

poppydog · 27th Jan 2021, 8:12 pm

I am making good progress on this thing albeit slowly but I have a couple more questions regarding capacitors this time.

C26 was getting warm and the wax was starting to melt creating waxicles so I cut it out and temporarily tacked 1 of those yellow polyprop axial types in for now. Can I leave it in there or do I really have to get 1 of those oblong x class caps for the mains filter in there instead?

C23 is a 16uf 350v rated electrolytic, its leaky so I need to replace it. I am having a bit of trouble finding something suitable to replace it with especially an axial type. What other value would be safe to stick in here?

There are quite a few black paper covered hunts in this thing, can they stay or should they get the chop, the radio is around 65 years old.

Poppydog

paulsherwin · 27th Jan 2021, 8:59 pm

It would be good practice to use an X2 in the C26 position, but a modern polyprop cap will be much more robust than what was there originally, and I doubt if there will be any problems.

C23 is just an HT decoupler and not at all critical. I would expect anything rated at 250V or higher and 8-100uF to be OK in that position. Obviously it's good practice to stay close to the original design value if possible, but it doesn't really matter.

Ekco tended to use lots of Hunts Mouldseals in the mid 50s, and all of them are pretty suspect, though opinions do differ about mass recapping.

Sideband · 27th Jan 2021, 9:02 pm

C26 should ideally be rated at 1000Vdc if you are going to use a polyprop. It isn't across the mains so doesn't have to be an X cap. Better to use a Y rated cap at 300Vac but you could use an X cap rated at 300Vac instead.

I would change all the Hunts caps while you have the chassis out. They will only cause problems later. I have one of these....in bits unfortunately since the cabinet was received as a jigsaw puzzle. The chassis is working fine as is the clock....that needed a thorough clean before it would run....the original oil had turned to goo so it was a complete strip and clean and then some proper clock oil.

The speaker was rattling and rubbing but I managed to take it apart and remove the rust from the magnet.

paulsherwin · 27th Jan 2021, 9:11 pm

You don't really need to use clock oil to lubricate synchronous electric clocks if you don't have any to hand. They are really just simple gear trains and very robust, so you can lube them with sewing machine oil, or even household oil like 3-in-1 or automotive engine oil. Mechanical clocks are a very different matter of course.

It goes without saying that you shouldn't use WD40 as a lubricant, though it can be used as an initial cleaner to free up the gunk.

poppydog · 8th Feb 2021, 6:25 pm

Thanks for all the previous replies.

I have now replaced all the sticky waxed capacitors bar C3, a pair of electrolytics C23 and C25 and all the paper covered hunts. C20, a paper covered hunts, the decoupler for UBF80 anode was the only 1 that was really bad. All the ceramic wax coated ones have been left alone.

I have tried checking resistor values as best I can but as most are still in circuit it’s a bit difficult to work out whats in spec.

When first powered up the radio wasn’t picking much up but after some minor adjustments I have radio stations on all four of the pre-sets, albeit a bit quiet.

Pos 1 I have Absolute fading in and out, (its doing very well to get that down here), Pos 2 Talksport, Pos 3 Radio 4 and Pos 4 Radio 4 on LW. The only issue I have now is that even after the things I have replaced the stations are still not very loud, it certainly wouldn’t wake you up in the morning even with the vol turned right up as far as it will go. There is no distortion when the vol is turned right up and the sound is very clear especially Radio 4 on LW. A length of wire stuck in the aerial socket in the back makes NO difference whatsoever.

If I get my signal generator with a 470kHz tone, turn the output of it right up and lay the lead from it near the frame aerial, you can vary the loudness of the tone with the vol pot of the radio and it really goes very loud.
I have done all the obvious such as made sure the waveband selector is clean and working as it should valve pins etc are spotless. Voltages I have taken are pretty good with regards to whats on the sheet.

Anybody any ideas please?

Poppydog

poppydog · 13th Feb 2021, 3:30 pm

This ones been "recycled", so the thread can be closed.

27th Jan 2021, 8:12 pm	#21
poppydog Banned Join Date: Oct 2015 Location: Cornwall, UK. Posts: 849	Re: Ekco A222 Resistor Query I am making good progress on this thing albeit slowly but I have a couple more questions regarding capacitors this time. C26 was getting warm and the wax was starting to melt creating waxicles so I cut it out and temporarily tacked 1 of those yellow polyprop axial types in for now. Can I leave it in there or do I really have to get 1 of those oblong x class caps for the mains filter in there instead? C23 is a 16uf 350v rated electrolytic, its leaky so I need to replace it. I am having a bit of trouble finding something suitable to replace it with especially an axial type. What other value would be safe to stick in here? There are quite a few black paper covered hunts in this thing, can they stay or should they get the chop, the radio is around 65 years old. Poppydog Attached Thumbnails

27th Jan 2021, 8:59 pm	#22
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Ekco A222 Resistor Query It would be good practice to use an X2 in the C26 position, but a modern polyprop cap will be much more robust than what was there originally, and I doubt if there will be any problems. C23 is just an HT decoupler and not at all critical. I would expect anything rated at 250V or higher and 8-100uF to be OK in that position. Obviously it's good practice to stay close to the original design value if possible, but it doesn't really matter. Ekco tended to use lots of Hunts Mouldseals in the mid 50s, and all of them are pretty suspect, though opinions do differ about mass recapping.

27th Jan 2021, 9:02 pm	#23
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,580	Re: Ekco A222 Resistor Query C26 should ideally be rated at 1000Vdc if you are going to use a polyprop. It isn't across the mains so doesn't have to be an X cap. Better to use a Y rated cap at 300Vac but you could use an X cap rated at 300Vac instead. I would change all the Hunts caps while you have the chassis out. They will only cause problems later. I have one of these....in bits unfortunately since the cabinet was received as a jigsaw puzzle. The chassis is working fine as is the clock....that needed a thorough clean before it would run....the original oil had turned to goo so it was a complete strip and clean and then some proper clock oil. The speaker was rattling and rubbing but I managed to take it apart and remove the rust from the magnet. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

27th Jan 2021, 9:11 pm	#24
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Ekco A222 Resistor Query You don't really need to use clock oil to lubricate synchronous electric clocks if you don't have any to hand. They are really just simple gear trains and very robust, so you can lube them with sewing machine oil, or even household oil like 3-in-1 or automotive engine oil. Mechanical clocks are a very different matter of course. It goes without saying that you shouldn't use WD40 as a lubricant, though it can be used as an initial cleaner to free up the gunk.

8th Feb 2021, 6:25 pm	#25
poppydog Banned Join Date: Oct 2015 Location: Cornwall, UK. Posts: 849	Re: Ekco A222 Resistor Query Thanks for all the previous replies. I have now replaced all the sticky waxed capacitors bar C3, a pair of electrolytics C23 and C25 and all the paper covered hunts. C20, a paper covered hunts, the decoupler for UBF80 anode was the only 1 that was really bad. All the ceramic wax coated ones have been left alone. I have tried checking resistor values as best I can but as most are still in circuit it’s a bit difficult to work out whats in spec. When first powered up the radio wasn’t picking much up but after some minor adjustments I have radio stations on all four of the pre-sets, albeit a bit quiet. Pos 1 I have Absolute fading in and out, (its doing very well to get that down here), Pos 2 Talksport, Pos 3 Radio 4 and Pos 4 Radio 4 on LW. The only issue I have now is that even after the things I have replaced the stations are still not very loud, it certainly wouldn’t wake you up in the morning even with the vol turned right up as far as it will go. There is no distortion when the vol is turned right up and the sound is very clear especially Radio 4 on LW. A length of wire stuck in the aerial socket in the back makes NO difference whatsoever. If I get my signal generator with a 470kHz tone, turn the output of it right up and lay the lead from it near the frame aerial, you can vary the loudness of the tone with the vol pot of the radio and it really goes very loud. I have done all the obvious such as made sure the waveband selector is clean and working as it should valve pins etc are spotless. Voltages I have taken are pretty good with regards to whats on the sheet. Anybody any ideas please? Poppydog

13th Feb 2021, 3:30 pm	#26
poppydog Banned Join Date: Oct 2015 Location: Cornwall, UK. Posts: 849	Re: Ekco A222 Resistor Query This ones been "recycled", so the thread can be closed.