Troubleshooting Pioneer CS-88s

Hello DIYers,

My dad recently gave me a set of Pioneer CS-88s (note: Not the 88As) he had laying in his garage for a long time. I have done some testing and am looking for further suggestions to getting them in working order.

Ultimately, one sounded good and the other didn't seem to work at first. I then bypassed the speaker terminals by connecting the speaker wire to the screws in the crossover circuit that the posts were supposed to transfer the signal to. This caused the bass woofer and the super-tweeter to come to life and start working. I started troubleshooting. I removed the leads from the bass woofer and touched them to the terminals of the midrange woofer, which seemed to work. I then thought that maybe the midrange leads were not carrying signal, but when I attached them to the bass woofer, that worked too. I then dismounted the midrange woofer and took a look--didn't see anything obvious. It seemed to be working with its original leads so I re-installed it. Everything was fine with that speaker until the next day and now it seems to be dead again. Why would a speaker work fine sometimes and be completely dead others? Sounds like a connection issue but I'm not sure how I can test/repair i.e. coil connections. Any thoughts?

In the process of removing the midrange and touching different leads to it, I did the same for a tweeter with the midrange leads (I've since found out this is a bad idea). It was completely dead and I haven't been able to get a sound from it. Are there any ideas you guys have for figuring out what exactly the problem with it is? Both tweeters seemed dead, but when I bypassed one of them from the circuit (they are connected in series) then the other one came to life. Does this imply that there is a broken connection in the bypassed tweeter? I guess a simple test would be measuring the resistance between the tweeter terminals and seeing if it's infinite?

Any thoughts/suggestions for additional testing or methods of repair if the problem is evident to you would be great. Thanks!
 

AllenB

Moderator
Paid Member
2008-10-18 11:31 am
With the tweeters in series, if one blows then neither will work. The best simple test is to measure the resistance between the terminals as you suggest.

You can retouch the solder joints to freshen them up. Consider any electrolytic capacitors to be suspect. Look at the resistors and inductors for signs of burning which you may also be able to smell from close up.
 
With the tweeters in series, if one blows then neither will work. The best simple test is to measure the resistance between the terminals as you suggest.

You can retouch the solder joints to freshen them up. Consider any electrolytic capacitors to be suspect. Look at the resistors and inductors for signs of burning which you may also be able to smell from close up.

I agree. I had a similar problem with my 88s turned out to be bad lytics.
 
Thanks, I'll check it out. So if I understand correctly you're saying that the reason the midrange might be cutting out is because of a bad capacitor in that section of the crossover but the tweeter is probably burned out since the other one works when it is removed from the circuit? If that's the case, is there a way to repair the tweeter aside from reflowing the the solder on the terminals? I tried that one already. Thanks again.
 
I found the problems and figured I'd post as a follow up in case it could help in the future.

The tweeter was showing an open connection across the terminals. Reflowing the solder didn't work so I decided to cut into it for investigation since I'm new at this. One of the connections under the paper on the other side of the terminal had come loose. Once I restored that connection I was able to get it to play sound, but the tweeter was trash since I removed all the paper--at least I know the problem.

The midrange speaker showed an open connection as well. Reflowing the solder on those terminals restored that connection. I now am left with the original speakers in tact and working, minus one of the tweeters.

Do you recommend I a) keep this configuration, b) replace the single tweeter, or c) replace all similar tweeters in both cabinets--4 in total--to have a complete and matched set? If you recommend option c, how much do you think that would cost? Thanks,

Zak
 

PJN

Member
2004-12-31 1:27 am
Pa, USA
Your best bet would be to look for a replacement tweeter on eBay. Any other option would cost more and could require a new crossover design. Just see if you can find an exact replacement, or a junk pair of speakers with a good tweeters. You might also want to replace all of the electrolytic caps in the crossovers with decent film caps.

PJN