DR 250 Capacitor question

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djtrumptight
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Joined: Tue Dec 15, 2009 6:08 pm
Location: Detroit,Michigan

DR 250 Capacitor question

#1 Post by djtrumptight » Thu Sep 10, 2020 9:48 pm

So,i havent used my system since early March so i decided to bring everything from storage to touch up all the paint,tighten all the drivers,replace all driver covers gasket tape etc...
i have been waiting 3 days for some better weather to take the system to a park and do some fine tuning before i put it up until hopefully next year.Meanwhile i brought my melded array DR250's inside to make some small adjustments and i noticed one playing a little stronger than the other.I did all the switching of signal cables and speaker cables,same outcome.I opened up the low playing DR to look at the filter and the small 15uf cap has some browning to it but its not busted,i also noticed its very close,like less than a 1/8 of an inch from the big coil that probably produces the most heat in the cab.I attempted to get a reading from it while still connected to the other filter components with my multimeter but the reading was erratic,it didnt go above 0.18.I took a reading from a brand new cap that i have on hand and it read like it was supposed to,it climbed up to 1.132 then started to drop so my question is,can i get an accurate reading if the cap is still connected to the other components ?
Built:
2 Autotuba's MCM 55 2421
8 T48's 24"wide 3015 LF
2 DR 250's melded Deltalite II 2510
2 DR 250's flat Deltalite II 2510
2 SLA HT systems
1 Table Tuba Dayton DCS 255-4
2 T 39's 20" wide 3012 LF
1 T-18 13" wide MCM 55 2421
2 SLA Pro's

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Bill Fitzmaurice
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Re: DR 250 Capacitor question

#2 Post by Bill Fitzmaurice » Thu Sep 10, 2020 9:59 pm

Unless you have a capacitance meter you can't measure a cap.

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: DR 250 Capacitor question

#3 Post by Grant Bunter » Fri Sep 11, 2020 1:35 am

Bill Fitzmaurice wrote:
Thu Sep 10, 2020 9:59 pm
Unless you have a capacitance meter you can't measure a cap.
+1

At this point, you have nothing to lose, and probably lots more to gain, by changing the potentially affected capacitor, and the location of the coil while you're there...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

SethRocksYou
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Location: Sacramento, California, USA
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Re: DR 250 Capacitor question

#4 Post by SethRocksYou » Fri Sep 11, 2020 2:06 am

Bill Fitzmaurice wrote:
Thu Sep 10, 2020 9:59 pm
Unless you have a capacitance meter you can't measure a cap.
I thought there were other tests you can do with a standard DMM that would indicate a failed/bad capacitor... No?
Two 2x6 shorty SLA Pro's
One 16" T39, 3012LF loaded
20" Tall AutoTuba loaded with 2 8" MCM 55-2421
8½" TruckTuba loaded with 2 8" MCM 55-2421

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Bill Fitzmaurice
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Re: DR 250 Capacitor question

#5 Post by Bill Fitzmaurice » Fri Sep 11, 2020 6:44 am

A DMM will only reveal a dead short or open circuit. It can't measure value. There can be shorted pathways inside the cap that cause major value deviations from normal.

djtrumptight
Posts: 814
Joined: Tue Dec 15, 2009 6:08 pm
Location: Detroit,Michigan

Re: DR 250 Capacitor question

#6 Post by djtrumptight » Fri Sep 11, 2020 10:02 am

Thanks Bill.
Seth that’s what I thought too,I guess not lol.
Grant,that’s what I did,I replaced the cap but mounted it farther away from the coil.
It’s now apparent that the speaker that was playing louder is actually the bad speaker,it sounded stronger in the low mids but the highs wasn’t as strong,what a difference a few blown tweets makes,I will replace the blown diaphragms before I take everything back to storage,meanwhile today is the dryest day we are gonna have for awhile,I’m gonna find a park and run all 8 subs and 4 DR’s,this will be my first time running all 8 subs correctly,the last time I did it I ended up with 2 blown subs because I lowered the hi pass to 35hz but didn’t stack the cabs,I had 4 side by side in each stack.
Built:
2 Autotuba's MCM 55 2421
8 T48's 24"wide 3015 LF
2 DR 250's melded Deltalite II 2510
2 DR 250's flat Deltalite II 2510
2 SLA HT systems
1 Table Tuba Dayton DCS 255-4
2 T 39's 20" wide 3012 LF
1 T-18 13" wide MCM 55 2421
2 SLA Pro's

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