DCP going south??

moewillis

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roccus said:
I don't believe I do there are a few differences if you are using stock backplanes or wopl backplanes I built mine with the wopl backplanes... you putting those in yours as well?? Shoot us some pics everyone loves pics :)
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i decided not to totally gut it so i stayed with the stock backplanes. it isnt a difference between comp or full comp or stock backplanes or not. the picture i have of the completed board looks like it has 2 resistors in r7 and r8 and i had no pack that made any reference to that position. i thought i had lost them but after seeing your board it has me wondering... maybe they are not needed??

ive been bad on this unit about taking pics. ive just been picking at it little by little. it took me forever to order parts for it. i havent devoted any really good chunks of time to it yet. i did get the caps and rectifier changed though. that old tape was a pain to get cleaned off. i found acetone to take it up pretty well though
 
jbeckva

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Crazy suggestion Ray, but double check the nuts bolting the DCP down. That was Ron's problem with a 400 I did for him awhile back - they worked their way loose. Give 'em another tightening and see ... :scratch:
 
roccus

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jbeckva said:
Crazy suggestion Ray, but double check the nuts bolting the DCP down. That was Ron's problem with a 400 I did for him awhile back - they worked their way loose. Give 'em another tightening and see ... :scratch:
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Will do.. maybe if that is a problem I will put a drop of lock tight on them
 
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Went through snugged everything up have not tested it after that Talked with the Carver specialist for near an hour on the phone brought up the WOPL and I asked him if he ever saw one he said he hadn't and didn't know much about them so I told him a bit about it he asked me if I could bring mine when I bring my C-1 so he could have a look see ....

I don't have a frequency generator to do step 8 all I have is a software driven app that can not apply voltages I did connect the amp to the variac to see if the votage has changed when it kicks in I'm pretty sure when I first put it in and tested it used to kick in about 60V now it don't kick in to about 78 volts... don't know if that means anything or not
 
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roccus said:
Went through snugged everything up have not tested it after that Talked with the Carver specialist for near an hour on the phone brought up the WOPL and I asked him if he ever saw one he said he hadn't and didn't know much about them so I told him a bit about it he asked me if I could bring mine when I bring my C-1 so he could have a look see ....

I don't have a frequency generator to do step 8 all I have is a software driven app that can not apply voltages I did connect the amp to the variac to see if the votage has changed when it kicks in I'm pretty sure when I first put it in and tested it used to kick in about 60V now it don't kick in to about 78 volts... don't know if that means anything or not
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Yeah it does, when you start cranking the amp, the supply will sag under the power load and probably kick out your relays.

You probably fried the sense chip that is used on the DCP.
 
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roccus said:
Went through snugged everything up have not tested it after that Talked with the Carver specialist for near an hour on the phone brought up the WOPL and I asked him if he ever saw one he said he hadn't and didn't know much about them so I told him a bit about it he asked me if I could bring mine when I bring my C-1 so he could have a look see ....

I don't have a frequency generator to do step 8 all I have is a software driven app that can not apply voltages I did connect the amp to the variac to see if the votage has changed when it kicks in I'm pretty sure when I first put it in and tested it used to kick in about 60V now it don't kick in to about 78 volts... don't know if that means anything or not
Click to expand...
Like Joe says, "yep, it means something" but not ready to say it's the DCP itself. Are you watching the DC level on the outputs as you bring up more and more voltage? From memory (forgive me Joe lol) I would say that with around 30 volts on the rails, the outputs should be zero'd out by then. If both channels are good and stable by 50 volts or so and the relay still hasn't kicked in, then yeah.. something's up with the DCP perhaps..
 
roccus

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jThanks Joe and JB this is the kind of info I need to get to the bottom of this.... Joe which part is the sense chip?? Also I see in the docs if bass gives you a problem you can change C7 to a higher value.. anyone know what that value would be??

I'm going to meet up with a Carver tech tomorrow he is going to take a look at my C-1 and the browndogs and all he would also like to see a WOPL so I'm bringing it with me tomorrow... to bad it is not running up to snuff so he could connect to some speakers and see what one of these can do but I will be able to point out to him the quality of the pc boards and parts that come along with the kit as well as how well things have been thought out and laid out everything is... I can only imagine he will be impressed
 
laatsch55

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The UPC1237 is not all that robust, I have fried a few myself. Check for DC on the outs and if there isnt, replace the UPC1237.
 
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Welcome Sir. There is a Chinese supplier on ebay that I have bought from and haven't got a bad one yet , but ya take your chances. That IC was obsolete 30 years ago and all nos NEC stuff is long gone...
 
roccus

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roccus

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laatsch55 said:
If they really are NEC parts I'd grab em.
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Thanks again Lee I just ordered 2 of them in case it turns out to be the problem.. I dealt with them years ago for imposable to find high wattage resistors used in tube jukes and they seemed pretty good.. you know anything about C7??
 
laatsch55

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Never had to change it. I think Don said it was good to 10hz IIRC. I have had some nuisance trips over the years but clips were involved too and a clip is seen as DC....
 
NavLinear

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roccus said:
Thanks guys I will have a look see... thing that is puzzling me is why did it just start doing this now and not from day 1? I did not run the frequency test when I did the build I did the dmb with a veriac hookup.... as some of you who followed my build will recall I hooked up to the wrong leg of the rectifier but once I got it on the right side of it on power up the relay on the DCP would kick in at about 60V

While I waited the 4 or 5 days for the new opamps to get here I was really enjoying the new amp and the C-1 everything was working perfect. When the opamps got here I out them in paying close attention to make sure I got pin 1 to go where pin 1 was supposed to go on both the surface mount opamps and then the adapters to the PC board. When I connected the C-1 to the 400 I was horrified as all I got was some static, popping, and squealing, the meters on the 400 were jumping all over the place something was really wrong with the adition of the new opamps.
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FYI - this was important information that would have had us hone in on a wounded DC protect board but Joe and Lee have you headed in the right direction. I purchased a couple of the NOS IC's also so thanks for the link. Good luck with the repair.
 
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Only problem I ever had with the DC protect was actually related to the fuse holders. Another gentleman had an issue with static electricity tripping the DCP when he walked across his rug and touched the faceplate, would trip everytime. Other then the fuse holders (which Jer fixed), I have run my 400s full snot w/ buried meters flat to the right with no problems
 
roccus

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Little up date got the the carver tecs house around 1/4 past 10 this morning he has all the happy equipment for this sort of work.. he worked on it till around 2 this afternoon he said he had other things that need to be done this afternoon he is not sure what is ailing it so I left it with him.. if he can't find the problem with it with all his happy equipment then I figure I stand 0 chance of nailing it down with just my simple scope and DMM... so that is how that went

Think I'll shut the shop down now and go in the house with my tail between my legs it's been a bad week......
 
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