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8th Aug 2021, 3:54 pm
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#1 |
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Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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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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8th Aug 2021, 4:09 pm
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#2 |
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Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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Re: Ekco U332
Have you monitored the HT voltage during warm up?
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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8th Aug 2021, 5:45 pm
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#3 |
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Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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Re: Ekco U332
No i havent not sure how to do that
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8th Aug 2021, 7:41 pm
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#4 |
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Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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Re: Ekco U332
Can any one tell me how to check the ht voltage if it goes down please
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8th Aug 2021, 8:27 pm
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#5 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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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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9th Aug 2021, 11:04 am
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#6 |
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Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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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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9th Aug 2021, 11:18 am
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#7 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Ekco U332
Output valve voltages?
Lawrence. |
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9th Aug 2021, 4:10 pm
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#8 |
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Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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Re: Ekco U332
Pin 9 is 44v Pin6 is 198v
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9th Aug 2021, 4:21 pm
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#9 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Ekco U332
Output valve voltages?
Lawrence. |
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9th Aug 2021, 4:26 pm
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#10 |
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Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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Re: Ekco U332
Not sure what you mean by value voltage
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9th Aug 2021, 4:30 pm
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#11 | |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Ekco U332
Quote:
Try valve electrode voltages. Lawrence. |
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9th Aug 2021, 4:32 pm
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#12 |
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Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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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.
__________________
Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. Last edited by Station X; 9th Aug 2021 at 4:42 pm. Reason: Circuit extract added. You're only getting the pentode section! |
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9th Aug 2021, 4:35 pm
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#13 |
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Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
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Re: Ekco U332
By output valve I mean the UCL82 as a whole....how hard can it be to measure the electrode voltages.....
Lawrence. |
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9th Aug 2021, 4:52 pm
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#14 |
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Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 21,289
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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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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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