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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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1st Aug 2022, 9:26 am | #1 |
Heptode
Join Date: May 2005
Location: Oxfordshire, UK.
Posts: 852
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Philips ISP IS5021
Hi All,
I have been asked to look at a Philips ISP IS5021............... ( https://www.dutchaudioclassics.nl/Fo...ound-enhancer/ ) It has failed on one channel and I have discovered it is the Right channel Volume Control which has physically broken and failed at zero Volume. The tiny spiggot which should protrude from the actual knob and mate with the Resistor actuator has snapped. I have attempted a repair and have been slightly successful but it is not as 'smooth' any longer, in feel and operation. I can find no service manual, Hi-Fi Engine etc etc. I have approached Dutch Audio Classics (see above) but as yet no reply. The control is an ALPS unit. 5 Pins and not a conventional Variable Resistor. It operates in the Digital Domain, I think, and varies a Voltage or Current. I think maybe Current as I can see nothing changing when 'scoping the Pins (on the good channel). One Pin sits at 5V, constantly and the rest appear 0V, constantly but the control is doing what it should on the good channel. I wonder, does anyone have a service manual for this and can give me the part number? Who knows, I may be able to find one somewhere. (Picture of disassembled control attached but not great quality, sorry. The long silver coloured protrusion is my 'fix' cut to a more appropriate length.) Thanks, James. Last edited by percival007; 1st Aug 2022 at 9:28 am. Reason: Added clarification |
1st Aug 2022, 11:05 am | #2 |
Hexode
Join Date: Dec 2020
Location: Raunds, Northamptonshire, UK.
Posts: 357
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Re: Philips ISP IS5021
if it works in the digital domain then it sounds like a rotary encoder rather than a potentiometer to me.
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Graham |
1st Aug 2022, 11:11 am | #3 |
Triode
Join Date: Dec 2021
Location: London, UK - Galicia, Spain
Posts: 30
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Re: Philips ISP IS5021
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If it ain't broke, don't try to fix it!! |
6th Aug 2022, 7:23 am | #4 |
Heptode
Join Date: May 2005
Location: Oxfordshire, UK.
Posts: 852
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Re: Philips ISP IS5021
That makes perfect sense that it is an encoder.
I haven't 'scoped any pulses on it, but i am sure that'll be what it is. Unfortunately I can't find the exact one at CPC/Farnel or RS. I shall have to scour eBay. Thanks for the pointers though. No-One got a schematic? James |
6th Aug 2022, 10:58 am | #5 |
Octode
Join Date: Dec 2019
Location: Owston Ferry, North Lincolnshire, UK.
Posts: 1,704
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Re: Philips ISP IS5021
Is the model number from the front or rear of the unit, as I don't recognise it as a Philips model. Most of the Philips model numbers start with 2 or 3 numbers followed by a couple of letters and then another few numbers, such as 22DC561 etc.
Dave
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Quote "All is hyperthetical, until it isn't!" (President Laura Roslin, Battlestar Galactica) |
6th Aug 2022, 9:56 pm | #6 | |
Heptode
Join Date: May 2005
Location: Oxfordshire, UK.
Posts: 852
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Re: Philips ISP IS5021
Quote:
it's what's on both the front and rear panels. See the pictures in the link in my first post (the Dutch Audio Classics link) James. |
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