DCP going south??

wattsabundant said:
I'm not very fond of just throwing parts at a problem. The most likely thing to happen by changing C7 is the board gets damaged. If anything verify it is the correct value. R3,4,5 should be 56K.
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R3,4,5 have 56.20K 1% resistors in there....

Lee sitting on my bench I don't have a fan on it it runs cool as a cucumber at low and moderate volume but when I crank (meters running in red a lot) it up it does run hot but with a fan on it it runs fairly cool
 
roccus said:
R3,4,5 have 56.20K 1% resistors in there....

Lee sitting on my bench I don't have a fan on it it runs cool as a cucumber at low and moderate volume but when I crank (meters running in red a lot) it up it does run hot but with a fan on it it runs fairly cool
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Resistors are in range...good to see it run cool...
 
Ahhh just found a way that constantly trips the dcp.. don't think this should do it I hooked up one of my TT's to preamp if I turn the loud switch on with full bass and turn it up I hear clicking noise from speakers and see the led's start to flicker and the dcp cuts out.... what do you think?
 
I think Don was right and yo u might have a subsonic transient. Is the turntable running??
 
laatsch55 said:
I think Don was right and yo u might have a subsonic transient. Is the turntable running??
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Yes I put a record on and crank it up then I hear the clicking snapping kind of noise come out of the speakers and see the LED's flicker when it cuts out
it seems it's the bass that is doing it when I hear the sapping I also see the meters peg out all the way to the right
 
think I just blew a woofer out of one of my 301's lol
 
If you are running with the loudness control in and the bass way up, then your turntable has some subsonic rumble......well there ya go.....
 
roccus said:
OK I will have a look at those... it has now been running for 3 days at all volumes and has not shut down so out of 100+ hours of running over the past few weeks it it has only shut down 2 times and when it did it was not cranking it was at moderate volume one last thing I will try when my load resistors get here is load the crap out of it as some here have suggested and see if I can get it to trip and maybe find a pattern that trips it then maybe I can get to the bottom of it
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That won't do shit. Who suggested that????

Yer grasping at straws. Might as well unhook the speakers.
 
I did , for one. A loaded amp acts a whole lot different than an unloaded one...
 
WOPL Sniffer said:
That won't do shit. Who suggested that????

Yer grasping at straws. Might as well unhook the speakers.
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I makes sense to me with a load your working the components without a load it would seem your just pushing air
 
Sorry for the WTF...... But I'm trying to figure out your troubleshooting path. Yer saying you crank the amp to max for hours, blow up a 301 (which by the way, only handles 130 watts ) with a WOPL 400 which can be near 250 plus watts per channel, then you do a drop check to your amp.... I'm trying to figure out why yer trying to figure out why your amp is having issues. Sounds like you already "loaded the crap" outta your amp. I know when I beat the hell outta my first car, I had to disassemble the engine to find the damage. When I had issues with one of my first amps, I disassembled that to do a good inspection. After all, after a sniff test when working on electronics is a thorough inspection. Tear it apart. Inspect (under magnification, check every solder joint, every resistor value, and ohm out every tranny etc...). Don't lead her to a slow death.
 
Guess I'm just a bull in a china shop
 
WOPL Sniffer said:
It does... But "Load the Crap out of it" ????? Makes no sense
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Sure it does. I take every amp I build ....to clip and beyond. I once took a 700 , loaded at 4 ohms to clip , it clipped at 775. I continued upping the input till the AP registered 1kw, which I thought was pretty dsmn cool, had never seen that before. Unloaded testing tells you a lot about how the amp behaves in a high voltage situation, adding a load turns the current up. Which can aid troubleshooting if a problem is current related. Granted, it can be a risk sometimes, and God knows I've blown up quite a few, but things were learned along the way and as a result Joe made some changes and the WOPLs were made more robust In the process.
It can be frustrating for those of us with no formal electronics training or engineering degrees. During 1 400 fix I had actually installed and replaced a total of 72 small signal transistors before I found the problem. That's why I show a lot of patience when helping others, cause I have probably been there and done that. And I have also done testing and replacement between recommendations and failed to inform those helping me of the additional steps taken leading to THEIR confusion.
This "remote help" process leaves a lot to be desired. It is difficult at best to determine someone's ability when they are anxious to get the problem solved and many prerequisites get short shrift. But, it is what it is, and we generally manage to muddle through the problem in spite of the shortcomings.

The one thing I have learned is that shot happens, often repeatedly, and sometimes for the same reason.....
 
Northwinds said:
Perry is good people and one hell of a tech Ray, maybe between the both of you this issue will be figured out
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I'm sure he is Ron but you have followed this whole build from start to now and have seen the conflicting advice I have gotten here and there I understand that everyone does things a little different and giving their honest opinion and I really do appreciate their input very much they are trying to help but it is hard to help without having the unit in front of them and I get that at this point I am willing to try anything. But I think what gets lost is previous posts on where I have been with this I have tried to be detailed and when I think I have found something turns out it does not pan out for instance yesterday I thought I had found a way to get the problem to reproduce and I think all will agree if you can't get the problem to reproduce you can not fix a problem you can not find it's like if you hear a noise in your car and go to a mechanic and the noise stops the mechanic can not tell you what is wrong or know where to look if the noise is not there when he listens to it.

I thought I had found a way to make the DCP trip with my TT connected put some bass on and crank it up it did trip first time I was able to get it to trip in 3 or 4 days and I got it to trip a second time right after that so I thought good now that I can get it to trip I can now do some trouble shooting... well I spent the rest of the afternoon trying to get it to trip again and pushed it so hard I blew a speaker never could get it to trip again. It's not like it trips every day or all the time it has tripped using both the C1 and the Pl3000 preamps it has tripped with my FM receiver and my TT so there is no one thing in common that produces the problem.

I was trying to find out some info but I think either it could not be answered or it went over everyones head. It is a logic question the damage seems to have occurred when I plugged the C1 in with bad opamps. So when you put an input into the PL what would be the first component that the bad signal would hit that could be damaged. The problem must be every now and then DC is getting into the output so to me that is 2 big clues as to where a good place would be to look where in the circuit can DC get into the output where is DC blocked from getting into the AC? And this goes back to what could have been damaged from the input that blocks the DC from getting into the AC? The rectifier? But I can not see how the rectifier would be affected from input.

It was suggested I send it out... what they don't understand is I am tapped out going into winter I have a lot of expenses vehicle maintenance, renew registrations, inspection stickers, insurance bill due, fill heating oil tank, a few cords of wood... ect ect. If I had plenty of money I probably would send it out at this point but I don't so I am trying very hard to get it fixed myself I put every spare minute I have into it I am still pouring money into it $5 here $10 there $20 or $30 over there.... I am doing all I can but it is clearly looking like peeps here may be loosing their patience with me. In 2 or 3 weeks I will be closing the shop down for the winter I was hoping I could fix it before then but it is looking doubtful that will happen. I am not ready to give up on it yet but am starting to get discouraged
 
Therein lies the rub. We also get discouraged and yes, you have gotten conflicting advice, and yes, it ain't perfect, but it is what it is.

At this point I would run it. Rack it up and enjoy it. Of you are running out of shop time and money, a DCP trip every few days isn't that inconvenient.

Some questions we ask MAY SEEM like an insult, but tis better to ask than assume. There has to be a baseline established and a thin skin is not helpful nor warranted, we are not here to ridicule nor gloat nor put down. We REALLY are wanting to help, but we also have other lives and making a living takes precedence ov r r this site at times. So even if things o
Move at a pace you find frustrating, be thankful it moves at all....
 
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