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Old 19th January 2013, 12:49 AM   #11
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Hi,
Did you check the output voltage when you power on the amplifier? Check the output voltage when you applied power to the amplifier. It is possible that the protection circuit it is detecting high voltage at the speaker output.
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Old 21st January 2013, 12:12 PM   #12
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Quote:
Originally Posted by tauro0221 View Post
Hi,
Did you check the output voltage when you power on the amplifier? Check the output voltage when you applied power to the amplifier. It is possible that the protection circuit it is detecting high voltage at the speaker output.
It's not detecting high voltage as it works as it should after the initial activation.

It seems the the initial inrushing d.c is causing the relay to momentarely activate, has anyone any other ideas?
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Old 23rd January 2013, 10:09 PM   #13
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Anyone?

Schematic below.
Attached Images
File Type: jpg accuphase e202.jpg (1.15 MB, 79 views)

Last edited by reddish75; 23rd January 2013 at 10:23 PM.
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Old 23rd January 2013, 10:28 PM   #14
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Hi,
Here it is a link for the services manual. Check page 12. It look like what it is doing is normal. In the power on the relay should energizes for 4 seconds and then drop.
Link:Accuphase E-202 | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine
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Old 23rd January 2013, 10:49 PM   #15
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Yep it does exactly what it says on page 12, I know how the protection circuit is supposed to and does work, but as I have said as soon as the power switch is pressed on, the relay connects the amplifier to the speakers for a split second then disconnects, it's not supposed to do that, after it does this it follows the normal protection circuit procedure.
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Old 24th January 2013, 12:28 AM   #16
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Hi,
Okay I missed the first part. Check then the transistors Q1 thru Q8. These transistors are the one that does the delay and check for output voltage to set or reset the relay. I will check Q3 and Q4. Q8 is the one that enable the relays.
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Old 24th January 2013, 11:22 AM   #17
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All the transistors check out.
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Old 24th January 2013, 04:58 PM   #18
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I did some checked and this it is what I think it happening at the power up. Q1 and Q2 are the one that sense high voltage at speaker outputs. Lets check the voltage at the base of Q1 when the amp it is power up. Check the voltage and it should read zero. When power it is applied voltage it is applied directly from the bridge to the base of Q3. I think the delay it is done in the Q3/Q4 by C2=10/25 volts and C3=33/volts. This will delay the close of the output relay at the power up. Check bot capacitors to see if they are OKAY. Do you have a scope?
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Old 30th January 2013, 04:06 PM   #19
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All voltages are correct apart from the base of q8 which reads 4v any idea why?
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Old 30th January 2013, 05:25 PM   #20
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HI,
I think 4 volts at the base of Q8 it is OKAY. To be able to close the output relay the base of Q8 must be positive. In the schematic showed that the base voltage should be 4.4 volts. In the explanation on page 12 for the circuit in the power ON it is say that the delay of 4 seconds it is done by the charging of capacitor C8. That will hold the relay open for 4 seconds. Can you check the voltage at the collector of Q6. If it is leaking it will charge the capacitor faster. It should be zero volts.
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