DCP going south??

roccus

roccus

Chief Journeyman
#82
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
#82
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....
Click to expand...
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
 
roccus

roccus

Chief Journeyman
#83
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
#83
laatsch55 said:
Just a slip of a probe on the backwall and you can have DAYS of work.....
Click to expand...
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
 
laatsch55

laatsch55

Administrator,
Staff member
#84
Joined
Jan 14, 2011
Messages
74,814
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#84
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.
 
roccus

roccus

Chief Journeyman
#87
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
#87
Does the 1237 chip have anything to do with what voltage the relay kicks in on power up?
 
roccus

roccus

Chief Journeyman
#89
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
#89
WOPL Sniffer said:
Can you at least try and remove it first without the speculation?
Click to expand...
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...
 
Gepetto

Gepetto

Administrator
Staff member
#91
Joined
May 15, 2011
Messages
13,927
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#91
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...
yes it does, it controls everything on that DCP board
 
WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#92
Joined
Aug 10, 2015
Messages
11,522
Location
Minnie-Soda
Tagline
Screw it
#92
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.
 
roccus

roccus

Chief Journeyman
#95
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
#95
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
 
roccus

roccus

Chief Journeyman
#97
Joined
Jul 4, 2016
Messages
1,112
Location
Maine
Tagline
You'll blow your ears out kid
#97
laatsch55 said:
No Ray, I've never seen one....
Click to expand...
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
 
Billboard

Billboard

Journeyman
#99
Joined
Nov 29, 2015
Messages
365
Location
North Shore Massachusetts
Tagline
---
#99
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?
Click to expand...
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.
 
grapplesaw

grapplesaw

Veteran and General Yakker
#100
Joined
Aug 13, 2014
Messages
2,775
Location
Vancouver
Tagline
---
#100
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.
 
Last edited:
You must log in or register to reply here.
Top