Penta 6603 muffled issues

[Raiderxx]

So I found a pair of Pentas, and just went through the process of refoaming the mid speakers. All in all not a bad job at all! Now, testing them our, it seems like one side works fine, but the other speaker seems incredibly muffled. I feel like I barely hear any bass, I can hear the theater pretty decently, but that’s about it. Definitely sounds muffled. I am currently running from my receiver to the red/black spring clamps. I havent had an opportunity to try the line in directly from my WiiM DAC. Any thoughts on what could be wrong? Happy to troubleshoot but re foaming the mid speakers has been my first foray into speaker repair so I might need some guidance. I am very comfortable with soldering, should I jump right into the amp recap kit? Or am I already bypassing the amp be coming from my receiver so that’s not really an issue? Any guidance would be great!

[Dillen]

Bad tweeter?
Mixed up orange wires for the midranges – or wrong polarization(s)?

Martin

[Raiderxx]

Alright. After closer inspection (ie, ear real close to each speaker), my tweeter works, and the top two and bottom two speakers are producing sound but are definitely not as loud compared to the right Penta. But my midranges on the left Penta are not working at all. I am 100% positive the wires are connected to the same connections they were when I got them (and based on the lady I bought them from, I don’t think there was anyone messing with these before me..). Speaker wire going to the spring clips should be bypassing the internal amps right? It’s got to be a wiring issue right??

 

Edit: Also, I’m pretty sure this was similar to before I re foamed the mid range speakers. But I only played them for a few seconds to confirm they actually worked. I remember one being a bit muffled even then but I took that quickly as an issue with the foam rot.

 

One more edit I promise.. I think the other outside mid range speakers on my right Penta are also not working.. I double checked the wiring against the schematic and the speakers appear to be wired correctly, although I did not try the other side of the wires inside the speaker assembly.

 

I lied. One more thing. As I was messing around listening to music for a half hour or so, maybe longer on and off, I just realized that the base is HOT. Is this a product of the mid range speakers not working or is there something else potentially going on? The right Penta is warm at the base but not nearly HOT like the left one.

[Dillen]

The warm amplifier section points to a bad idle current trimmer.
Replace the trimmers (there is one for DC offset as well) and adjust them as
mentioned in the service manual.
– Or grab a kit that also contains new capacitors and a slight upgrade to the signal path.
Kit here.
Other parts here.

Martin

[Raiderxx]

Thanks Martin! Could that be the reason the mid range speakers aren’t producing much if any sound? If so I’m pulling the trigger! Replacing the caps was next on my list, just trying to make sure I’m on the right path and not sinking hundreds into these..

[Author]

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