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Old 21st October 2012, 04:43 AM   #11
RS232 is offline RS232  United Kingdom
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Join Date: Jan 2006
Location: Swindon
Got amp up and running.
Found out the problem with the on and off, if power up with the light bulb protection there is not enough juice for the relays to latch and the empty capacitors would cause a big inrush of current and make the light bulb go on if left like that after 6 or 7 latches it would stay on.
Now something else...
If I go close to the 11 o'clock position on the dial the amp just disconnects the speakers and I'm starting to give up on it.
Speakers ? they are some vintage Leak ones rated at 50W if I'm not mistaken.
Will try later with other ones and see what happens.
Any suggestion ?

Ric
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Old 22nd October 2012, 06:24 PM   #12
OXAUDIO is offline OXAUDIO  United Kingdom
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When the amp disconnects with the volume control at '11o'clock, are you still powering it via the lamp limiter?. Additionally, is this happening with a signal applied to the input, possibly at too high a level?
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Old 23rd October 2012, 01:52 PM   #13
RS232 is offline RS232  United Kingdom
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Problem solved.
The amp was connected to the line without the bulb limiter and to a CD player.
The problem was the connector from the mainboard to the front panel.
Connected the amp to a set of speakers that can handle the power of the amp gave it a good blast (past the 12 o'clock mark) and no more problems
If someone is repairing this 900MK2 please make sure the 4 connectors are properly connected to the front panel boards.

Ric
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Old 24th October 2012, 10:01 AM   #14
OXAUDIO is offline OXAUDIO  United Kingdom
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Quote:
Originally Posted by RS232 View Post
Problem solved.
The amp was connected to the line without the bulb limiter and to a CD player.
The problem was the connector from the mainboard to the front panel.
Connected the amp to a set of speakers that can handle the power of the amp gave it a good blast (past the 12 o'clock mark) and no more problems
If someone is repairing this 900MK2 please make sure the 4 connectors are properly connected to the front panel boards.

Ric
Presumably there were dry solder joints between the connectors and the PCB, Ric?
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Old 24th October 2012, 01:50 PM   #15
RS232 is offline RS232  United Kingdom
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Location: Swindon
Quote:
Originally Posted by OXAUDIO View Post
Presumably there were dry solder joints between the connectors and the PCB, Ric?
Actually there are no dry solder.
The plastic part of the connector(s) are "L" shaped and they have some up/down movement and is what causes the problem.
After putting the front panel back in place just press the 4 connector into the front panel board and that's it (well in my case it solved the problem).

Ric

Last edited by RS232; 24th October 2012 at 01:53 PM.
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