DCP going south??

roccus

roccus

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laatsch55 said:
I have ruined quite a few new stuff!! When an amp goes POP, SQUEAK< BANG from bad pre-amp, it's not the amps fault. Transients can cause hell....
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Thanks Lee for confirming what I suspected in the beginning that the preamp did something to the amp but was told a preamps low power output would most likely NOT cause damage to an amp... so lets say the preamp did cause damage what could get damaged that would up the DC current to the outputs?? The amp still sounds great I just can't crank it as the DCP shuts the output down
 
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laatsch55 said:
Just a slip of a probe on the backwall and you can have DAYS of work.....
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I really have not had much time to dig into this yet this week as I had so much on my plate but will get into it tomorrow so if you can load me up with tests abd if you can point me in a direction I will try what Nav said and bypass the DPC and check milli volts but keep in mind the DCP does not kick in till I apply at least 75V from my vatiac which suggests a problem with the DCP
 
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The transient was probably at a level and frequency way beyond normal, and being transient in nature , did a smash and grab with the circuitry, what still stands out in my mind is that the relay still clicks. IIRC , when you mentioned first, there was no mention of a relay click. Have you checked the input to the DCP with a scope?? Did you check the pass thru contacts of the relay with a scope, to trace the signal path thru the dcp might help.
 
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Does the 1237 chip have anything to do with what voltage the relay kicks in on power up?
 
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WOPL Sniffer said:
Can you at least try and remove it first without the speculation?
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Yes just trying to arm myself with some info for tomorrow while you guys are here I may have more than one problem here and am trying to figure one at a time When I first installed the DCP 60V tripped it now it takes 75V just trying think out why this would change so was just wondering if the 1237 has anything to do with the power regulation to the relay switch...
 
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roccus said:
Yes just trying to arm myself with some info for tomorrow while you guys are here I may have more than one problem here and am trying to figure one at a time When I first installed the DCP 60V tripped it now it takes 75V just trying think out why this would change so was just wondering if the 1237 has anything to do with the power regulation to the relay switch...
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yes it does, it controls everything on that DCP board
 
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roccus said:
Yes just trying to arm myself with some info for tomorrow while you guys are here I may have more than one problem here and am trying to figure one at a time When I first installed the DCP 60V tripped it now it takes 75V just trying think out why this would change so was just wondering if the 1237 has anything to do with the power regulation to the relay switch...
Click to expand...
Once you get the DCP out of the way, you will verify your amp first. Then we can see what is going on instead of all the WHAT IF.....

I'll step back and let the pro's help you.
 
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WOPL Sniffer said:
Once you get the DCP out of the way, you will verify your amp first. Then we can see what is going on instead of all the WHAT IF.....

I'll step back and let the pro's help you.
Click to expand...
This is what I will do as I remember one of the recommendations on the build was do the build in steps one row of transistors at a time then test then test before installing the DCP all this to help find a problem before to much is done

Thanks guys for your input I now have a direction to start with and more
 
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laatsch55 said:
No Ray, I've never seen one....
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Top secret lol but I'm good to go for now you all gave me some real good info first I will disconnect the DCP and see where the amp is at without it.... again thanks all
 
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roccus said:
Finally catching up on stuff around here and am going back to the 400 to try some of the tests sent to me here... one question I had the was never answered was about step 8 in the DCP manual...

"8. If a signal generator is available insert a 1KHZ sine wave into the left channel. Set the
generator level to obtain 40 VAC on the amplifier output."

I do not have a signal generator that can apply voltage all I have an app to run out of my laptop. Would it be the same if I just put 40V to the amp with a variac then apply 1Khz from my laptop to get same results?
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Did not see an answer to this one, I will try.

You can use your computer as a signal generator, when the instructions say to turn it up until you have 40 volts on the output, they want you to increase the input until the amp outputs 40 volts peak to peak (no load) on the outputs. You will need a scope to check the output voltage. This should be done at full AC input, no variac.
 
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Billboard said:
Did not see an answer to this one, I will try.

You can use your computer as a signal generator, when the instructions say to turn it up until you have 40 volts on the output, they want you to increase the input until the amp outputs 40 volts peak to peak (no load) on the outputs. You will need a scope to check the output voltage. This should be done at full AC input, no variac.
Click to expand...
Some sound cards cannot put out more than 1 volt. Check the spec on this for your sound card. You will need up-to 1.75 volts to drive it. Just a cautionary note. I had issues with a sound blaster card doing this.
 
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