2.3 xover pcb missing cap since new!

C3 Audio

I picked up a pair of used SDA SRS 2.3's over the weekend from the original owner. You can read about them in the "Vintage Speaker" forum titled "Adding SDA SRS 2.3's to the family".
Initial listening and inspection of all the drivers and tweeters at the sellers house indicated all was well. After a thorough cleaning, I hooked them up to my home system and noticed the top left side tweeter didn't seem to be working. No crackle, no buzz, hiss, nothing. All other drivers were fine. I figured the tweeter was toast. I thought maybe the poly switch might be problematic, but a quick look at the schematic indicated that if the poly switch opens, all the tweeters would be silent, not just one. There is a capacitor and a resistor in line with this specific tweeter, but I figured the tweeter was most likely shot.
Tonight I removed the tweeter and ohmed it out. Much to my surprise, the meter read 8 ohms like it should? After feeling confident that the tweeter was working, I moved to the crossover. It looked easy to pull, so I removed the xover from the cabinet for testing.
Tracing the schematic for the top tweeter I found the .4mH inductor and 22.5 ohm resistor, R3, but couldn't find the 5.x uF cap in line with the tweeter. After doing a lot of checking and double checking and much to my surprise, the cap was missing from the board. Gone, never there since the xover was assembled. To the best of my knowledge, these cabinets had never been opened? The missing cap certainly explained why the tweeter didn’t work.
The SDA SRS 2.3 schematic on the Vintage Speaker forum just happens to be hard to read in the area where the missing cap is located. The best I can tell is that the value is 5.x uF, so hopefully someone will be able to tell me the correct value and type of this component?

I’ll continue in a response to this post……..

C3 Audio

The picture below is of the xover as I removed it from the cabinet. The missing cap goes between holes “A” and “L”. While I didn’t photograph the back side of the board, there is no solder in the area where the cap belongs, so this tweeter has never worked since the speaker was manufactured.

Any help identifying the cap value and style will be greatly appreciated.

Thanks for your help,

C3

Face

http://www.polkaudio.com/forums/showpost.php?p=677959&postcount=5

avguytx

Is it like this on the other crossover too?

Edit: I think you are correct. Here is a picture of the 2.3 Crossovers I redid for my buddy before the new caps. It clearly shows the cap is there across the terminals you stated. I had to rotate it 180 degrees so that's why the date is upside down.

C3 Audio

avguytx wrote: »

Is it like this on the other crossover too?

Edit: I think you are correct. Here is a picture of the 2.3 Crossovers I redid for my buddy before the new caps. It clearly shows the cap is there across the terminals you stated. I had to rotate it 180 degrees so that's why the date is upside down.


All drivers and tweeters work fine in the right speaker, so I figure the cap is there. I haven't opened the right speaker, but I could if need be, to get the cap value.

C3

avguytx

No need. 5.8uf 50v cap is what's there.

When the time comes around, they would benefit greatly from a cap/resistor freshening but that's personal choice.

C3 Audio

avguytx wrote: »

No need. 5.8uf 50v cap is what's there.

When the time comes around, they would benefit greatly from a cap/resistor freshening but that's personal choice.

Avguytx,

Thanks!
That is exactly what I needed.
5.8uF 50v non-polarized electrolytic
It was impossible to read the 8 on the schematic.

Yes, I agree with you on the cap/resistor upgrades and will probably do so down the road.

Thanks again,

C3