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Technics SU V505 problems
Technics SU V505 problems
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Old 8th July 2014, 08:07 PM   #21
ironcobra is offline ironcobra  Portugal
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Old 9th July 2014, 06:25 AM   #22
Mooly is offline Mooly  United Kingdom
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Technics SU V505 problems
Are you sure they are resistors ? There are such things as "zero ohm resistors" which manufacturers fit in place of wire links (they use them because they can be placed automatically just like other components).
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Old 9th July 2014, 01:22 PM   #23
ironcobra is offline ironcobra  Portugal
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yes are resistors but in low-cut, they are very old and colors to identify the value are burned.
thank you
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Old 9th July 2014, 01:36 PM   #24
Mooly is offline Mooly  United Kingdom
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Technics SU V505 problems
We would really need to see the actual circuit diagram in order to come to some kind of conclusion as to what they are.
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Old 9th July 2014, 02:28 PM   #25
KatieandDad is offline KatieandDad  United Kingdom
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Resistors very rarely, if ever, fail short circuit, they usually fail open circuit.
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Old 10th July 2014, 04:00 AM   #26
Ian Finch is offline Ian Finch  Australia
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I can't be certain what those "resistors" are connected to from that diagram. It would be easier to post a link to the full service manual schematic and assembly diagrams, free here: Technics SU-V505 Manual - Stereo Integrated Amplifier - HiFi Engine

I can faintly make out that those 2 circled items J, J are connected to pins 8&9 of the connector and pins 18 & 10 of the AN7062, respectively. They would have to be jumpers or links for that to be the case. If you confirm what they connect to on the little board, you have your answer.

At least you will be able to read off resistor values from the parts list if they are a part of the voltage amplifier section. It seems IC71 is our old unfavourite AN7062, so there will some experience out there with this easily fried chip.
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Old 16th July 2019, 04:33 PM   #27
dynoPort is offline dynoPort  Wales
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I'm attempting repair to one of these with very bad distortion on right channel. Done a lot of component testing.... R205 is a short but resistor itself is ok out of circuit. I don't know if it's the balance pot itself I dont think it is

also diode 720 is giving a reading in the wrong direction but it's an unusual one?
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Old 16th July 2019, 05:27 PM   #28
dynoPort is offline dynoPort  Wales
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Also, no bias current at all to adjust on right channel test points tp306 - tp304, left ok
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Old 16th July 2019, 06:35 PM   #29
SVI2004A is offline SVI2004A  New Zealand
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Technics SU V505 problems
What voltage at collector of Q304?

R205 (R206) are shorted by to ground by loudness switch in OFF position.
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Last edited by SVI2004A; 16th July 2019 at 06:42 PM.
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Old 16th July 2019, 07:23 PM   #30
dynoPort is offline dynoPort  Wales
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Quote:
Originally Posted by SVI2004A View Post
What voltage at collector of Q304?

R205 (R206) are shorted by to ground by loudness switch in OFF position.
from base & emitter I assume? around 39v DC. Zero from chassis
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