My favorite Polk Monitor 10 tweeter is not working: suggestions?

Scott H B

Greetings forum,

Reaching out for counsel and please redirect me if this is not the right forum. I have a cherished pair of Polk 10 monitor speakers (not sure if 10a or 10b or 10) and have recently moved residence. In the process of rewiring my system I sadly noticed my tweeter was not functioning on my right speaker.

I thought maybe it was moving damage due to something hitting the tweeter but when I swapped tweeters of which both work fine on the fuly functional speaker. I isolated that is not the physical tweeter that is broken but whatever crossover electronics driving the tweeter. I am reaching out for counsel on next steps to self repair or where I can get replacement parts etc. Am an out of practice electrical engineer but am not adverse to tinkering and would hate to give these beauties up if it were a capacitor.

Photos are attached as I am not confident if these are 10's, 10a's or 10b's

Scott

Mystery

Peerless tweeter suggest it's 10A.
If the tweeter is working in another speaker, it's the crossover component that needs to be looked at as you mentioned.
Wait for comments from experienced members to troubleshoot.
If all connections in the board are solid, probably a capacitor or resistor is blown.

BTW, what's that red lining on the dust cap of PR?
Never seen red color there on Polks.

Scott H B

thanks much Mystery. I recall many years ago I had to replace that PR and its probably not an original component. Also rookie question but to access the crossover hardware is it best to access it from the front via the mid range woofers, subwoofer etc?

TNHNDYMAN

Not trying to overstate the obvious, but have you checked the fuse on the back of the bad speaker? Also look for loose wires inside from crossover to the tweeter. Can you see if the capacitors have any obvious damage - bulging or leaking? Should be a simple fix and with your background a capacitor upgrade should be easy and very rewarding. Good luck.

TNHNDYMAN

Scott H B wrote: »

thanks much Mystery. I recall many years ago I had to replace that PR and its probably not an original component. Also rookie question but to access the crossover hardware is it best to access it from the front via the mid range woofers, subwoofer etc?

The crossover should be attached to the binding post cup on the back. Just disconnect the drivers and then remove the binding post cup from the back of speaker to inspect the crossover.

pitdogg2

TNHNDYMAN wrote: »

The crossover should be attached to the binding post cup on the back. Just disconnect the drivers and then remove the binding post cup from the back of speaker to inspect the crossover.

take a close look there is no binding post cup. It appears to be on PB wonder if that is glued to the back of the box?
I would also look at the fuse try a new one as those can be hard to tell be the naked eye.

TNHNDYMAN

^good eye, my mistake. Those are very early in the series. OP will probably have to remove drivers and go thru the passive rad hole to check the crossover board to see how to remove it if necesarry.

Scott H B

Thx TNhndyman and pitdogg2. Yeah i did swap out the fuses between the good vs. bad speaker and no resolution. Yes that rear assembly of the binding post is fully glued. I took a look inside by removing the passive subwoofer and could not see any loose connections, solders or blown equipment. Photo attached. Very simple circuitry but now comes the fun part of figuring out what is broke.

transmaster

Gosh you are making things so complicated. The Tweeter in the other speaker is working pull it out and hook it up on the other speaker if it works as I suspect it will you have found your problem. The replacement for later model 10's is RDO-194, I am not sure what Polk has for the Peerless tweeter It could be the same tweeter. For proper sound you will have to replace both tweeters. You
also should re-cap your crossovers so you can really hear how good a Polk Monitor 10 can sound.

Scott H B

thanks Transmaster and all for your time and counsel. Transmaster, unfortunately the functional tweeter swapout did not work in the disfuntional speaker assembly so by proxy of process elmination of also swapping out fuse etc am leaning toward crossover circuitry as the faulty item which visually appears ok and connected solidly. Fun

jon s

Well, the 10s crossover is a very simple design... You might as well replace the caps and the resistors with new ones as teh caps tend to degrade over time which will affect the crossover point. You can buy relatively cheap caps such as Jantzen and Mills resistors from Parts Express. Or you can get SoniCaps which seems to be very popular amongst the tweakers around here.

All you need is a soldering iron and some solder... It is quite easy to remove and replace the components. If you are not comfortable with this, there is surely someone you know who can tackle this job with no problems. You can also go to YouTube and search for soldering videos. There are some posted and you can see if is quite easy to do...

transmaster

Scott H B wrote: »

thanks Transmaster and all for your time and counsel. Transmaster, unfortunately the functional tweeter swapout did not work in the dysfunctional speaker assembly so by proxy of process elimination of also swapping out fuse etc am leaning toward crossover circuitry as the faulty item which visually appears OK and connected solidly. Fun

You are going to want to rebuild your crossovers anyway. One of My 10B's actually had a capacitor that had blown up. I used Sonicaps Gen 1 for the high side and Axon True Caps for the low side. I eventually had to replace all of the drivers, Polk Audio has replacements. The Sonicaps Gen 1 can be purchased here: http://www.soniccraft.com/sonicaps.htm I was told and it turned out to be excellent advice not to get really expensive caps for the low pass side. So there I used the Axon True Cap's. The Axon's are $6.50 each for the 250V 33 micro farad capacity Considering the Sonicap Gen 1's for the low side on a Monitor 10 are nearly 50 dollars each I saved enough money to pay for the Sonicaps for the high pass side. The Axon True Cap's can be purchased here: http://www.partsconnexion.com/capacitor_film_axon.html should you not want to spend the money on the SonicCap Gen 1. The Axon True Cap's are much better then the degraded non polarized electrolytic's that are there now. They will vastly improve the sound for a very good price. While you are at it replace the resistors with the Mills wirewound non-inductive resistors, cheap and much better the what is there now. There are other non-inductive resistors but the mills are the easiest to find.

Incidentally the resistance in Ohm's at the speaker binding posts at the back should be about 6.3 ohms in a working 10B.

The improvement in the sound on my Monitor 10B's is amazing, I purchased these speakers new in 1989 and they have never sounded as good as they do right now.

Scott H B

thanks for the scoop on the hardware transmaster. two quick follow up questions...assume I should then likewise swap out the hardware on the functional speaker as well so that the speaker hardware is the same? Additionally assume I can leave the coil (photo above) and the coils behind the assembly intact without replacement?

pitdogg2

FWIW the last month there has been some monitor 10 binding cups on ebay might make it easier

mhardy6647

The OP's photo shows an original Polk Audio Monitor Series Model 10 (unsuffixed, and pre- "Monitor 10" appelation, too).
Note the uncoated paper passive radiator; that's an old one!

mhardy6647

Saftgeek

Nice post Mr Mh... Cool ad.

Saftgeek-

F1nut

Clean the contacts on the fuse holder.

halo71

My favorite Polk Monitor 10 tweeter is not working: suggestions?

Sorry to hear this. But what did the other tweeter do to make you not like it? 'Cause I like both my Monitor 10 tweeters equally.

edwardm10

mhardy6647 wrote: »

I wonder what a setup like this in today's world would go for?!?

mhardy6647

Less than 999 with a little luck and planning.

transmaster

Scott H B wrote: »

thanks for the scoop on the hardware transmaster. two quick follow up questions...assume I should then likewise swap out the hardware on the functional speaker as well so that the speaker hardware is the same? Additionally assume I can leave the coil (photo above) and the coils behind the assembly intact without replacement?

The inductors (wire coils) will be just fine no need to change them. Replace both tweeters, always in pairs. The Peerless is no longer made so The RDO-194 is it's replacement. I don't know about the Peerless tweeter but I can tell you the RDO-194 blows the doors off of the SL-2000's the 10B's had. I assume the 10A had the 6 1/2" MW-6503's If they start to fail the modern replacement sounds, to my ears at least, the same as the original. The only visible difference is the modern driver does not have the little solder points on the speaker cone, instead the wires coming up from the voice coil go directly to the terminal strip. I think this is an improvement because not having that mounting point of the speaker cone removes a tiny amount of weight from the speaker cone which will let it move just a tiny amount easier. While you are refurbishing your 10A's get Weld Bond Epoxy and apply it to the magnet assembly on the MW-6503's. The Glue that holds the magnet in place is fairly weak and a thump to the speaker can dislodge the magnet locking up the voice coil. Apply JB Weldbond around the edge where the magnet emerges out from the top and bottom plate will prevent this from happening.

Incidentally the working Peerless tweeter will find a ready buyer on this forum should you want to part with it.

westmassguy

transmaster wrote: »

The inductors (wire coils) will be just fine no need to change them. Replace both tweeters, always in pairs. The Peerless is no longer made so The RDO-194 is it's replacement. I don't know about the Peerless tweeter but I can tell you the RDO-194 blows the doors off of the SL-2000's the 10B's had. I assume the 10A had the 6 1/2" MW-6503's If they start to fail the modern replacement sounds, to my ears at least, the same as the original. The only visible difference is the modern driver does not have the little solder points on the speaker cone, instead the wires coming up from the voice coil go directly to the terminal strip. I think this is an improvement because not having that mounting point of the speaker cone removes a tiny amount of weight from the speaker cone which will let it move just a tiny amount easier. While you are refurbishing your 10A's get Weld Bond Epoxy and apply it to the magnet assembly on the MW-6503's. The Glue that holds the magnet in place is fairly weak and a thump to the speaker can dislodge the magnet locking up the voice coil. Apply JB Weldbond around the edge where the magnet emerges out from the top and bottom plate will prevent this from happening.

Incidentally the working Peerless tweeter will find a ready buyer on this forum should you want to part with it.

The RDO-194 is not the direct replacement for the Peerless. There is none. The 194 is listed as a replacement for the SL1000 and SL2000. The original 10s had MW6501s according to the Polk schematics.
The trim plate for the 194 is slightly larger than the Peerless, so some modifications will be required.
The crossovers are also slightly different depending on which tweeter was used orignally. Luckily, for the 10s it's a matter of one resistor value change.
You can download the original, and revised schematics here: http://www.polkaudio.com/forums/showthread.php?38755-POLK-AUDIO-Speaker-Wiring-Schematics-amp-More-ALL-MODELS-except-SDA

Scott H B

Thank you all for your invaluable input! I will write back after I complete the replacements and repairs. May be a while as we just moved in to a new home and the honey do list is pretty large!

Scott H B

Forgot to ask one question..when it comes to replacing the cap's and resistors, since the crossover hardware is attached to the binding post assembly which is glued to the back of the box, should I attempt the repair by forcefully removing the whole glued unit or is it reasonable for me to try to re-soder it while in its current position (assuming I'll need to remove some foam etc)

westmassguy

Scott H B wrote: »

Forgot to ask one question..when it comes to replacing the cap's and resistors, since the crossover hardware is attached to the binding post assembly which is glued to the back of the box, should I attempt the repair by forcefully removing the whole glued unit or is it reasonable for me to try to re-soder it while in its current position (assuming I'll need to remove some foam etc)

From the posted photo, it appears there's a large phillips head screw holding the crossover in place. I would try to persuade the crossover loose, rather than working down inside the cabinet. For component replacement, you'll want full access to the underside. Soldering blindly from above is not good practice. You could very well end up with cold solder joints, or worse.