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Capacitor Rabbit Hole. Just How Do You Measure?


Dave A

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8 minutes ago, mboxler said:

What do others think about electrolytics, like the 33uf ones that come with E2 crossovers?

EV uses them in their crossovers in the woofer circuit as well so I would thing that they're not that concerned with using a more expensive cap for that particular job.

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23 minutes ago, RandyH000 said:

... the AA XO was operative on the mids and woofer but fainter on the tweeter and the tweeter was not the issue , what is the only  part  left - the cap for the tweeter ... 

The tweeter on the AA is attenuated by the T2A. 

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10 minutes ago, Deang said:

Uh, no. They always run a diagnostics test. That's how they get the code.

To be clear, pulling a code is the first step in diagnosing something.  You need the code to tell you what diag to run.   It doesn't tell you what part to replace like parts houses would lead you to believe.

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3 minutes ago, CECAA850 said:

To be clear, pulling a code is the first step in diagnosing something.  You need the code to tell you what diag to run.   It doesn't tell you what part to replace like parts houses would lead you to believe.

How do you guys "get the code". 

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9 minutes ago, Deang said:

How do you guys "get the code". 

Hook up to the data link connector under the dash.  You access the module and record the code.  Take the code then look up the diagnostic procedure for that particular code and follow the trouble shooting tree.

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49 minutes ago, Deang said:

Uh, no. They always run a diagnostics test. That's how they get the code.

Retrieving a code is not what I call a diagnostic test. For instance if you have an oxygen sensor code it does not necessary mean you need an oxygen sensor. A component in front of the oxygen sensor could be the problem. Running too rich or too lean is an example. I took my car in for repairs having an injector code. I did not have the proper noid light to test whether the injector was getting the signal to fire. The shop just retrieved the code and installed an oxygen sensor and sure enough it was not the problem. A rat, squirrel, chipmunk had chewed a wire into. If they had done some diagnostic work first I would have not had to pay for an oxygen sensor along with fixing the wire. Sadly this is the case with many or most shops. 

 

Carl can better explain this fact of most shops better than I. It has been 20 years since I worked on electronics on a car. 

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30 minutes ago, CECAA850 said:

To be clear, pulling a code is the first step in diagnosing something.  You need the code to tell you what diag to run.   It doesn't tell you what part to replace like parts houses would lead you to believe.

Well said. Your customers are fortunate to have your shop to go to. I wish I could find one in my city I could trust.  

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27 minutes ago, Deang said:

How do you guys "get the code". 

There are code retrievers for sale at Amazon now for around $30 that do the same as ones I paid $1500 for 20 years ago. The one I bought for $30 a few years ago does much more than retrieve codes. Lets you see the data stream as well. Worth the investment for everyone before you take a care in for repairs. I use to have a mechanic shop myself. Now I am too old and in bad health to get under a car or do any manual labor. 

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38 minutes ago, Deang said:

The tweeter on the AA is attenuated by the T2A. 

 

 

36 minutes ago, CECAA850 said:

Details.......................

-- T2A was ruled out , as well as the diodes as the tweeter was not open , and  DCR  reading was up to  specs -

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4 minutes ago, henry4841 said:

Well said. Your customers are fortunate to have your shop to go to. I wish I could find one in my city I could trust.  

We pull customers from other dealerships regularly.  My shop has 3 Master techs.  2 of them I've grown from lube techs.  I've taught them not to take short cuts. They document what they do, no more no less.  All 3 of my guys can follow a diagnostic tree to a T.  I'm now trying to get them to think outside the box as far as trying to see what the diagnostics are trying to tell them.  For example, when you check a wire for continuity, opens or shorts, why are you checking that particular wire and what does it do.  Diag trees aren't perfect and in some cases have typos.  If you know where they're going and what they're trying to find out, many times you can look at a schematic and diag it on your own.

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12 hours ago, Dave A said:

I have used the K-55 M and V drivers on the AA crossover. I like that crossover the most so when I used to get La Scalas I would put AA's in there. Both drivers sounded fine to me when in good condition. I have had problems with buzzing from M's because the plastic cap on the back gets loose. Bead of silicone around it solves that. I have also had problems with both types not sounding quite right even though they would ohm the same and sounded OK with a frequency sweep generator. In retrospect I should have had a known top condition K-55 to contrast the old one to when doing the frequency sweep. What happened is I would put them back in and it still did not sound right. Talking to Crites about diaphragms because I was to that point on a set and he mentioned that they had some older drivers that ohmed and swept OK but did not sound right. So I bit the bullet and put new diaphragms on a pair of these and they sounded right. The M is harder to replace the diaphragm. I prefer the V for these reasons but use either with confidence.

Oddly, I have had each and every condition you mention in your post from the rattle back of the M to the V that tested great, sounded off, new diaphram and sings beautifully again. I am confident in the AA with the 55M as I have had that configuration for four or five years in a pair of LS that sound great to anyone that has heard them. I don't tinker nearly as much as you so a little disappointed that I have kept up with the problems. You need to try harder.

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3 minutes ago, RandyH000 said:

 

 

-- T2A was ruled out , as well as the diodes as the tweeter was not open , and  DCR  reading was up to  specs -

And exactly how did you come to this conclusion?  How was the T2A "ruled out"?  and how does the DCR have any bearing at all on this?  I find it remarkable that you can make these statements without a shred of background.  Are you simply parroting someone else, and cutting and pasting from other sites?

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15 minutes ago, henry4841 said:

Retrieving a code is not what I call a diagnostic test. For instance if you have an oxygen sensor code it does not necessary mean you need an oxygen sensor. A component in front of the oxygen sensor could be the problem. Running too rich or too lean is an example. I took my car in for repairs having an injector code. I did not have the proper noid light to test whether the injector was getting the signal to fire. The shop just retrieved the code and installed an oxygen sensor and sure enough it was not the problem. A rat, squirrel, chipmunk had chewed a wire into. If they had done some diagnostic work first I would have not had to pay for an oxygen sensor along with fixing the wire. Sadly this is the case with many or most shops. 

 

Carl can better explain this fact of most shops.  

Then you had a circuit code then.  Most guys don't know the difference between a circuit code (circuit high, circuit low) and a performance code.

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I follow Steven (Youthman) on YouTube. He had a pretty good video of him troubleshooting the problem. Steven swapped tweeters, networks, etc. I think Randy was just saying it was process of elimination. Most of the time it will be a capacitor related issue. We are just saying don't call yourself a repair center if all you do is send out capacitor kits. 

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5 minutes ago, jimjimbo said:

Would that be "B" for Bourbon?

I stopped when the pandemic hit. I haven't had anything since last March. I started teleworking and they made me responsible for the junior engineers, so I had to give it up.

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