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Old 8th Aug 2021, 2:54 pm   #1
Dorian27
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Default Ekco U332

The above radio on switch on for about 3 to 4 min the volume is high as normal but after 3 to 4min it just goes right down low in one go not slowly but immediately. Can any one help? Don't know where to look. I have changed the coupling capacitor. But still drops as I said not gradually but immediately. Any one now what it might be? The volume when it goes down is still audible but if you want more there is none.
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Old 8th Aug 2021, 3:09 pm   #2
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Default Re: Ekco U332

Have you monitored the HT voltage during warm up?
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Old 8th Aug 2021, 4:45 pm   #3
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Default Re: Ekco U332

No i havent not sure how to do that
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Old 8th Aug 2021, 6:41 pm   #4
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Default Re: Ekco U332

Can any one tell me how to check the ht voltage if it goes down please
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Old 8th Aug 2021, 7:27 pm   #5
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Default Re: Ekco U332

Between the +ve of C27 and chassis and between the +ve of C26 and chassis.

Approx. 160 Volts DC and approx. 94 Volts DC respectively according to the service info when supplied with 240 Volts mains.

Lawrence.
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Old 9th Aug 2021, 10:04 am   #6
Dorian27
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Default Re: Ekco U332

Hi i have taken HT readings go steady as follows C27 is 196/7v and C26 is 90/91v
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Old 9th Aug 2021, 10:18 am   #7
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Default Re: Ekco U332

Output valve voltages?

Lawrence.
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Old 9th Aug 2021, 3:10 pm   #8
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Default Re: Ekco U332

Pin 9 is 44v Pin6 is 198v
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Old 9th Aug 2021, 3:21 pm   #9
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Default Re: Ekco U332

Output valve voltages?

Lawrence.
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Old 9th Aug 2021, 3:26 pm   #10
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Default Re: Ekco U332

Not sure what you mean by value voltage
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Old 9th Aug 2021, 3:30 pm   #11
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Default Re: Ekco U332

Quote:
Originally Posted by Dorian27 View Post
Not sure what you mean by value voltage
Neither do I because I didn't say "value"

Try valve electrode voltages.

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Old 9th Aug 2021, 3:32 pm   #12
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Default Re: Ekco U332

Lawrence said output valve voltages.

The output valve is V3B, the pentode section of a UCL82.

Pin 6 Anode.
Pin 7 Screen Grid.
Pin 2 Cathode.
Pin 3. Control grid.

Valve pins number clockwise from the gap or spigot when seen from under the chassis.

The DC voltages should be measured with respect to (WRT) chassis.

All this is in the manufacturer's service sheet, which is where I got it from.

EDIT. Posts crossed.
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Last edited by Station X; 9th Aug 2021 at 3:42 pm. Reason: Circuit extract added. You're only getting the pentode section!
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Old 9th Aug 2021, 3:35 pm   #13
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Default Re: Ekco U332

By output valve I mean the UCL82 as a whole....how hard can it be to measure the electrode voltages.....

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Old 9th Aug 2021, 3:52 pm   #14
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Default Re: Ekco U332

Very difficult I'd say. It seems to be the very last thing some repairers and restorers want to do. Far easier just to change components in case they're faulty.

I'm an old school dinosaur who adopts a logical approach to fault finding. Meter before soldering iron!
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