Pioneer Cs-a700 Crossover

dneu201

Well-Known Member
I'm in need of finding a replacement crossover for one of the Pioneer Cs-a700 speakers I found at a resale shop. So far, both speakers have been recapped, but the one not working has had the mid range, and tweeter replaced (both blown) but still has issues putting the receiver into protect mode. I'm thinking it could be an inductor or the switch, but have no way to test these.

Anyone have parts for these speakers for sale?
 
Good luck finding a replacement. Do you have a schematic of the xover? I found the service manual at hifiengine. They are usually easy to figure out, but you need test equipment, at least a DMM. This one is a bit more complicated, but should be fixable, if you know where to look.
Inductors usually do not short out, if anything they go open, but you have to measure each of them anyways. The docs are very good. The inductors are iron core, so they have low resistance.
I hope you used good quality bi-polar 100V min ecaps.
Wondering what you used to replace the old blown speakers with?
 
I used Dayton audio capacitors recommend on another audiokarma thread for these speakers. As for replacement speakers, I was able to find the exact replacement parts on eBay.

Would the best option for testing the inductors is to compare the two crossovers? Or would an open inductor show infinity on my mm?
 
Yes comparing good vs bad is a good idea. use the MM of course.
yes an open shows infinity or overload, but you are saying the xover shorts out the amp, so you are looking for a short not an open.
 
Ok. I'll open the good speaker back up to compare. The speaker at full range reads .4 ohms while the good one is approximate 7.6 ohms.

I just need to trace the wires through the schematic to only look at the full range. The 3 way and 2 way Bi amps work fine and show correct readings.
 
Sounds like you are on the right track to a solution. I am guessing a wiring error when you did the recap.
 
The recap shouldn't of caused the issue as the amp was being put in protect mode before I recapped the speaker. If I bypass the large inductor and connect speaker wires, the speaker sounds fine. I'm wondering if that full range inductor could be having issues.

My father in law has a friend that repairs speakers here in Houston. He might be willing to take a look at this one. Worse case scenario I find a used and working crossover on eBay for $20-$30 and recap that one. These would be fun speakers to keep beside my Forte II's for A and B.
 
Look at the schematic and refer to the comp in the schematic.
What actual audio caps did you use? Dayton what?
The speaker at full range reads 0.4 ohms while the good one is approximate 7.6 ohms. So where is the short then, it is only a few components.
And if you open one of the woofer connections, the short is still there, and the woofer measures what R?
I assume that you thought that re-capping would solve your short issue.
Follow the schem, the big inductor(L1,4.5mH) is in series with the woofer. the schem, which shows full range switch setting,
1) Full range input + terminal goes thru L1 to s1-12 & C1(50uF), s1-12 connects thru the wafer to s1-9 to the woofer +. C1 goes to full range - terminal.
woofer - goes to s2-9, thru wafer to s2-12, onto full range - term. Pretty straight forward.
So C1 is in parallel with the woofer = 12dB/oct LPF
You can use the same logic to follow the rest of the paths.
Like I said previously, good luck finding a xover on ebay. Could be years away, if ever, no guarantee. This should be easy to fix.

You have the good working xover and I assume the other speakers are fine to compare against as well.

If you know someone who can help and follow a schem, of course take that course of action if you can not figure it out.
And of course you cleaned the switch contacts,wafers with deoxit D5, which should have been done to start with.

Good luck
 
I ended up dropping the speaker off at the shop to be looked at by my father in law's friend, but he also couldn't pin point the issue. He was under the impression something could have went wrong with the switch. I currently haven't had luck finding a new crossover online. I'm considering just bypassing the switch and wiring the crossover to be in full range at all times until I find a new crossover. Would this be an option y'all would recommend as a temporary fix?

Thanks.
 
To bad you and your friend can not figure out the exact cause of the short.
I am not sure what you mean by "wiring the crossover to be in full range at all times"?
I hope you do not mean to hook your amp up directly to the mid range and tweeter drivers, as that will blow them.
The schematic is drawn showing full range op. It is confusing to follow, I agree, it is a 3 throw 9 pole switch.

To make better sense of it, I would re-draw the schematic to follow the signal paths as they pass through the switch and passive comps in full range mode. Using 3 hi-lighter colours to follow the path of the signal thru the switch contacts and drivers. A good exerciser in electronics.
That is a mess of re-wiring to remove the switch. To me it means you have to understand the schematic fully as to what paths to follow in the first place.
 
Hey. I forgot to update you all. I was able to find a $25 crossover on eBay from a seller whom had previously sold me a replacement tweeter. It came in Saturday. Within an hour and a half of receiving the crossover, recapping it, and attaching it I had both speakers playing on my Pioneer SX-650.

What I meant by bypassing the switch was wire it in full range mode, defeating the 2 way and 3 way settings. But the crossover I found helped me avoid this.

Here are pics of the setup.
 

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My apologies for the incredibly basic question, but how do you go about removing the crossover to work on it without damaging it/or the cabinet? I have a set of these and need to do a rebuild, can't figure it out
 
You actually don't need to remove the crossover, just the back panel. Take all the screws out the back. I had to gently hit the speaker on a towel on the ground for the back panel to come off. If the wires come undone, you can follow the service manual to connect everything back. I used dayton audio capacitors (with the exception of the larger cap for the woofer), which were a bit large but I was able to glue some of them in a different location.
 
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