DCP going south??

roccus

roccus

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Went back up laid the face plate out of the way and saw R24R is also burnt to a crisp on control board also R25 in right backplane looks like it has a dark ring in the center of it so it may also be damaged and getting strange results looking at Q6 right backplane board will have to pull that out of circuit to see pico fuses did not blow so looks like I have taken 4 steps back and for sure I will have to order parts again this shows the importance to nit put a wrong value resistor in the wrong place I think when I put the 13k resistor in R24 it must have damaged something hen when I put the I think it's 180k back in what ever the 13k damaged the correct resistor let burn up along with other components like a chain reaction
 
roccus

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Hey Ron how you doing?? I guess I can say so far I have had a lot more aggravation with this amp than enjoyment it has spent more time on the bench than in my system but I think eventually it will get sorted as I do have some great help here from others the thing that is killing me is having to put orders in for parts it seems almost every week now for it which also slows any repairs down to a crawl I will say for the short while it was up running good I loved it
 
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If it says anything, I have a fair amount of parts in my inventory since I began building. I popped a few components when I started. I hated to wait for shit so when I needed stuff, I ordered an extra one here and there. All components are pretty cheap except the outputs. And learn? Indeed...... that's that's the beauty of it. I went through some typos too. The time I got sent old instructions and that sucked because they had you solder in the outputs........ Yup, we've come a long way baby..........

Knock on wood, ain't had an issue since I learned what I was doing.
 
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Yep Perry, Sabbitha is still cranking the shit out of my world. A friend on AK is sending me a new set of tweeters for my D9's. I don't really like the horn bullet tweeters at high output levels. He has a set of HED series CV soft dome covered ones that will drop right in. I guess they were also in Polk's early KG series. I believe he said they were Heppner Dhorm Tweeters. They also were used in Altec 890c Bolero's
 
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roccus

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Here is what I have found blown so far.... all on right channel but something could also be blown on left channel as well as both 5A fuses blew but been concentrating on right for now as /i can see visible damage no visible damage on the left channel

Bad parts on backplane right side... R31, R23, Q6
Bad parts on control board right side... R24, D9





 
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I see an emitter resistor gone, not surprised Q6 is gone with that blown resistor in it's path...


With an emitter resistor looking like that you also have a shorted output....



On a 400 the 5amp negative rail fuse is for BOTH channels, same for the positive rail fuse...so...you can blow both fuses from having a problem on only one channel...
 
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laatsch55 said:
I see an emitter resistor gone, not surprised Q6 is gone with that blown resistor in it's path...


With an emitter resistor looking like that you also have a shorted output....



On a 400 the 5amp negative rail fuse is for BOTH channels, same for the positive rail fuse...so...you can blow both fuses from having a problem on only one channel...
Click to expand...
Thanks Lee for taking a look I need to get an order together you think I may have output transistors blown to? I know I'm gonna have to rip this thing back down to near bare chassis... all that hard work to put it together last summer down the toilet.....:sad7:
 
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You don't normally blow fuses without having a shorted output, it CAN happen, but usually from being overdriven...
 
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laatsch55 said:
I see an emitter resistor gone, not surprised Q6 is gone with that blown resistor in it's path...


With an emitter resistor looking like that you also have a shorted output....



On a 400 the 5amp negative rail fuse is for BOTH channels, same for the positive rail fuse...so...you can blow both fuses from having a problem on only one channel...
Click to expand...
If Q6 goes, the bias jumps to a very large value which will take out emitter resistors. They are flameproof types so they fail open gracefully.
 
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Gepetto said:
If Q6 goes, the bias jumps to a very large value which will take out emitter resistors. They are flameproof types so they fail open gracefully.
Click to expand...
Hi Joe... yea you can see one blown out in my second pic
 
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WOPL Sniffer said:
If it says anything, I have a fair amount of parts in my inventory since I began building. I popped a few components when I started. I hated to wait for shit so when I needed stuff, I ordered an extra one here and there. All components are pretty cheap except the outputs. And learn? Indeed...... that's that's the beauty of it. I went through some typos too. The time I got sent old instructions and that sucked because they had you solder in the outputs........ Yup, we've come a long way baby..........

Knock on wood, ain't had an issue since I learned what I was doing.
Click to expand...
I understand this for you where you build many of these things but I'm just looking for 1 decent running amp in all my life of stereo gear I have owned I have never had to stock parts for any of them so I'm think what do I have to do... order enough components to build another wopl to be sure I have everything I may need to get this thing fixed?
 
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