DCP going south??

roccus said:
All I have is a DMM, an oscope and an app to send signals from my laptop but it wont put any voltage out... anyone here have a signal generator they will part with??
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Your computer does output voltage, it is measured in AC peak to peak, I believe you need close to 2 volts peak/peak to drive the phase linears to full boogie. The more you turn the volume up on your computer the more you drive the amp.

Your computer probably does not output 2 volts pek/peak, but may have enough output from your computer to drive your amp to where the problem surfaces.

So use your computer to drive the inputs of the amp, then watch the outputs with a scope with nothing connected to them (no load).

Lee can step you through this, if you need an 8 ohm load for testing they are available on ebay for short money.
 
Funny thing. I just heard about this simple executable file a few months back from a friend. It's basic but effective for checking your hearing for range and your particular heads/ears angle of incidence, generating tones to feed into your inputs to check Dolby tracking .... lots of fun stuff.

Do you know why the audio spectrum is limited or is set at 20,000 Hz in component specs or output range? Because most people (think bell curve), can't hear much above 10,000 Hz to 15,000 Hz and the roll-off in the perception of loudness beyond that is dramatic and typical audio spectra that is materially relevant to the hardware that needs to reproduce that sound, needs to be spec'd out beyond the average & usable range to maintain the best possible "flatness" in the range that matters - the meat & potatoes.

Try it with some headphones and see where your hearing limits are. :happy2:

Here's a web based one that works with Chrome & Firefox that has some add functions. Handy if you have a laptop.

http://onlinetonegenerator.com/frequency-sweep-generator.html

Here's the sweeping hearing test on the same site:

http://onlinetonegenerator.com/hearingtest.html
 
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grapplesaw said:
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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Check the output with the scope as well to check for distortions. These may put out the higher voltage but no always clean signal
 
Billboard said:
Your computer does output voltage, it is measured in AC peak to peak, I believe you need close to 2 volts peak/peak to drive the phase linears to full boogie. The more you turn the volume up on your computer the more you drive the amp.

Your computer probably does not output 2 volts pek/peak, but may have enough output from your computer to drive your amp to where the problem surfaces.

So use your computer to drive the inputs of the amp, then watch the outputs with a scope with nothing connected to them (no load).

Lee can step you through this, if you need an 8 ohm load for testing they are available on ebay for short money.
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Being a laptop probably not that much but.... to use it the signal comes out the headphone output I have a cheap headphone amp kicking around somewhere it may very well put the 2V out what if I go from laptop headphone out to headphone amp then onto the PL?
 
Ok guys, sorry I've been awol on this one.

My test set for the 400 boards includes a BGW 750 module that I drive with a HP204C oscillator. The oscillator will go down to about 3 hz. The test set has switches so that I can drive either input to the board. I test the contacts with a Dale 250W/8 ohm resistor on the output of the board and watch it on a scope. The board trips around 5-7HZ with the BGW clipping at around 35VAC RMS. After it trips at sub audio frequencies I then drive the BGW across the audio band to make sure it won't trip at audio frequencies.

Anything is possible, including a DCP that is acting up, but this sounds to me like the board is doing what it's supposed to which is disconnect the output in the presence of very low frequencies including DC.

I've seen receivers that tripped at low bass which I assume is intentional by the mfr to protect the amp. The intent of the DCP is to stay out of the way and only trip if the amp fails.


Yea, I've been on the road probably as much this year as ever. It is hard to keep up. I try to scan the emails when I have a chance. Heading to Bahrain/Dammam Saudi Arabia tomorrow.
 
Damn Don, I knew you went around the country, now you're going around the world??
 
Was going to try to do some testing today but... 250W resistor needed?? wow I don't have anything close to that.. also don't have a clue what he is talking about HP204C ocsillator or BGW 750 all I have is a simple audio generator :???:

wattsabundant said:
Ok guys, sorry I've been awol on this one.

My test set for the 400 boards includes a BGW 750 module that I drive with a HP204C oscillator. The oscillator will go down to about 3 hz. The test set has switches so that I can drive either input to the board. I test the contacts with a Dale 250W/8 ohm resistor on the output of the board and watch it on a scope. The board trips around 5-7HZ with the BGW clipping at around 35VAC RMS. After it trips at sub audio frequencies I then drive the BGW across the audio band to make sure it won't trip at audio frequencies.

Anything is possible, including a DCP that is acting up, but this sounds to me like the board is doing what it's supposed to which is disconnect the output in the presence of very low frequencies including DC.

I've seen receivers that tripped at low bass which I assume is intentional by the mfr to protect the amp. The intent of the DCP is to stay out of the way and only trip if the amp fails.


Yea, I've been on the road probably as much this year as ever. It is hard to keep up. I try to scan the emails when I have a chance. Heading to Bahrain/Dammam Saudi Arabia tomorrow.
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Well I decided since I don't have everything needed here for Don's testing I just connected it to a preamp with an mp3 player for input and cranked the bag out of it as this is what was tripping it in the first place... been running wide open near 1/2 hour now and still running strong no DCP tripping.. so may have been the the 1237 chip on the dcp which I did change also the reason for loosing -15V on the control board was VR2 the TL431 IC it must have blown
 
Just need for the pico fuses to get here to replace the blown one I have a 10ohm 1/4w resistor piggy backing it for now then button it up...

fixing_zpsfcipcyhs.jpg
 
laatsch55 said:
Good work Ray, ya been rompin on it ????
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Always do Lee!! thanks for your assistance as well as others who have also assisted in this thread... I got something in the works and if it pans out I think I will have to do some wopl work on the stock 400 to do a bi amp set up......
 
laatsch55 said:
Damn Don, I knew you went around the country, now you're going around the world??
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Yea we're doing some work with Aramco. You go where the work is.

Just got back. 25 hour flight. Miss connected in Frankfurt because Lufthansa employee deployed emergency exit slide while on the ground. Departure from Bahrain was delayed for 2 hours.
 
25 hours....jeez....I get antsy about 2-1/2 from Rapid to Phoenix....
 
Here is latest om my wopl 400 after about 50 hours running it something is still not right all power test points test good now I replaced the 1237 chip on the DCP board... in the 50 hours I have run it hard wide open, moderate, and low volume the DCP has tripped 2 times in the 50 hours both times at moderate volume never wide open or low volume so I don't feel I can button it up and put it back in my main system yet. When all this started the DCP would trip every time I run it hard within a couple minutes so it has improved a lot but something some where still not right. I have ordered a 300 watt 8 ohm load resistor but it won't be here for awhile coming from china so I can so some further testing.. I don't have a clue what I'm looking for though and being interment may be a bitch to track down also considering just pulling the DCP out and be done with it
 
Sounds like your DCP is working fine, I wouldn't remove it.

I am sure you will figure it out, once you get the 8 ohm dummy load see if you can duplicate the shutdown at will. Run the amp at different frequencies from the tone generator from your PC, and also at different levels.

Stick with it you will get it.
 
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