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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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16th Feb 2019, 10:35 am | #21 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: Hacker Cavalier with dimming output
..or C8 is leaky
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16th Feb 2019, 9:29 pm | #22 |
Retired Dormant Member
Join Date: Feb 2019
Location: Waterlooville, Hampshire, UK.
Posts: 21
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Re: Hacker Cavalier with dimming output
HI All
once again many thanks for your time on this. have included a picture of the latest findings - point a - 253 vdc b 271 g 199 h 249 i 4.5 j 0 k 4.7 c and e both hit around 50 then nose-dived d and f hit the 20's then went south too l onward where 0v x 191 and y 21 with this measuring 1k9 the resisters at i and k both measured 189 ohms which I don't think is good. the 10k R10 couldn't be found on the part of the board I have been looking at. R15 came in at 949 ohm the rest are in the picture. c8 is next on the hit list. as for meter - I use a fluke 12b which is autosensing since the last set of batteries died in my avo. |
16th Feb 2019, 10:08 pm | #23 |
Dekatron
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Location: Cornwall, UK.
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Re: Hacker Cavalier with dimming output
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16th Feb 2019, 10:11 pm | #24 |
Retired Dormant Member
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Re: Hacker Cavalier with dimming output
lol - thats good news . ... not
ok where should I be going from here |
16th Feb 2019, 10:14 pm | #25 | |
Moderator
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Re: Hacker Cavalier with dimming output
Quote:
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Graham. Forum Moderator Reach for your meter before you reach for your soldering iron. |
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17th Feb 2019, 8:22 am | #26 |
Octode
Join Date: Dec 2018
Location: Llandeilo, West Wales, UK.
Posts: 1,092
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Re: Hacker Cavalier with dimming output
Morning opus,
That pretty well confirms what we are all thinking, C8, the blue 8uF one, has failed seriously and gone low resistance. It will need to be replaced by a 10uF 300 volt cap. The 10K resistor R10 is the one I marked on the picture last time (post no. 19?) and is the one you have between x and y. That too will be a dead duck now, so order a 10k ohm 2 or 3 watt replacement. While you wait for parts, you could try removing one leg of the blue cap and see if the voltages improve. Station X, yes a bit of a jigsaw, but we at least know what opus is referring to using his 'method' Alan PS, forgot to say about the resistors marked i and k, they are the cathode resistors R13 and R14. I would replace them too with the correct value, 220 ohms 2 or 3 watt types, as it will run the valves just a little 'cooler'. And I have re-posted the location drawing so we can all see what is what... A
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Never Leave Well Enough Alone... Last edited by snowman_al; 17th Feb 2019 at 8:38 am. Reason: PS added |
17th Feb 2019, 9:02 am | #27 |
Dekatron
Join Date: Aug 2013
Location: Wigan, Greater Manchester, UK.
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Re: Hacker Cavalier with dimming output
R15 a 1.5k seems low according to the photo, shown as 900ohms.
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Frank |
17th Feb 2019, 9:41 am | #28 |
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Re: Hacker Cavalier with dimming output
Many thanks to everyone.
What wattage are looking for r15.? Don't think I have had a resistor go like r10 before Thanks again |
17th Feb 2019, 10:29 am | #29 |
Octode
Join Date: Dec 2018
Location: Llandeilo, West Wales, UK.
Posts: 1,092
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Re: Hacker Cavalier with dimming output
Hi opus,
May I suggest that before you order a new R15, you measure its resistance 'out of circuit' ? It might be that C11 and C12 are also leaking electrically, as well as C8, and are effectively in series with R12 when in circuit. Unsolder one end of R12 and then take a reading. That way it is not connected to other components and will give you a true measurement. If it is closer to 1.5K out of circuit it does not need changing. If it stays at 900 or so ohms then a 3 watt 1.5K ohm replacement will be fine.
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Never Leave Well Enough Alone... |
17th Feb 2019, 5:52 pm | #30 |
Retired Dormant Member
Join Date: Feb 2019
Location: Waterlooville, Hampshire, UK.
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Re: Hacker Cavalier with dimming output
Thank you all.
As per Alan and Nuvistor I have swapped out the resistors and caps( a tad over the top as had a selection of 5watts and 350v parts ) and joy of joys I have noise. Many thanks to you all... Now where is that Dynatron..😁 |
18th Feb 2019, 7:51 am | #31 |
Octode
Join Date: Dec 2018
Location: Llandeilo, West Wales, UK.
Posts: 1,092
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Re: Hacker Cavalier with dimming output
Good news.
Just one more thing before you leave it, just make sure the big can capacitor, C11 and C12, is not getting warmer (or hot even) than the chassis. If it is, best to replace it/them. Alan Now where is that Dynatron...
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Never Leave Well Enough Alone... |
18th Feb 2019, 11:16 am | #32 |
Hexode
Join Date: Dec 2018
Location: Sheffield, South Yorkshire, UK.
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Re: Hacker Cavalier with dimming output
that's good, I love a happy ending
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18th Feb 2019, 11:58 am | #33 | |
Retired Dormant Member
Join Date: Feb 2019
Location: Waterlooville, Hampshire, UK.
Posts: 21
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Re: Hacker Cavalier with dimming output
Quote:
I didn't notice last night but then wasn't looking for that. I did see that is a dual/double cap and was surprised not to see it leaking when I first fired up, so will double check. thanks |
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