polk monitor 10b crossover issue

Mr. Sharpe

Okay so I finally replaced the caps in my monitor 10's with dayton's. Before this in one speaker only the tweeter was and is still working but the woofers are not, the ohm meter reads 0 ohms for the speaker, but the tweeter is working... but not loudly. I hooked the woofers up separately and they work but not while hooked to the speaker. it's not any kind of amp issue or wiring issue because my other speakers are working perfectly fine.

I see there is a small little blue thing on the crossover board, polyswitch maybe? can the speaker just not work at all if there's an issue with this? like I siad it's only in one speaker. please help.

I did not replace the resistors and hopefully that isn't part of the problem.

F1nut

You should always upgrade the resistors while in there. Anyway, the blue thing is the poly, so remove it and replace with a jumper. However, I don't think that's your problem, so while you're in there retouch all the solder joints on the board. Also, inspect for a broken lead on the inductors. Report back.

Faustin

You can also use a .5 ohm resistor in place of the polyswitch. If you do (and like F!nut said you should) replace the resistors, you can mount them on the bottom of the board if there is not enough room on the top.

Mr. Sharpe

okay, I didn't know you could just use a jumper for the little switch. cool thanks hopefully that'll fix it up.

Mr. Sharpe

I heard somewhere you shouldn't mix mills with sand cast resistors, why is that? and Madisound has matching ones to replace these don't they? I haven't really looked.

F1nut

Because sand cast resistors suck. Shop at Sonic Craft.

Mr. Sharpe

Lol okay then.... looks like sonic craft has absolutely every possible value of resistor you could ask for and a good price! great! thanks so much sir.

Mr. Sharpe

I should just replace the resistors with the same value as the old ones shouldn't I? A thread I saw here said 10 watt and a 12 watt resistor, my speakers have both being 5 watt resistors. Same resistance.

http://forum.polkaudio.com/discussion/164500/monitor-10b-crossover-upgrade-parts-confirmation

westmassguy

The 5 watt resistors heat up quite a bit. I've rebuilt dozens of Monitor Crossovers with burned out resistors and scorched circuit boards. The 10 or 12 watt Mills will do nicely, and won't heat up as much. Just make sure the value in ohms is the same.

Mr. Sharpe

Sweet! had no idea, that's awesome!

Mr. Sharpe

I have completed the upgrade, used Dayton caps for highs and lows and mills for the resistors, those are really nice. and still have the same results. no lows, very faint highs. what happened? everything is connected and soldered inside, did I blow them?

Faustin

Can you post detailed pictures of the completed crossovers? Perhaps someone can spot a problem.

westmassguy

Something is profoundly wrong. If the woofers are not producing any sound, check that the large spool inductor is connected to the circuit board:



When you had the circuit board removed, were the black and white wires coming from the binding posts intact?

bigaltx24

Print out the schematic, if you haven't already, grab your VOM and check continuity on all the drivers. Then starting from the terminals check continuity to the crossovers and just keep on going till you get to the drivers. It's a fairly simple circuit, you'll eventually find your problem.

Mr. Sharpe

westmassguy wrote: »

Something is profoundly wrong. If the woofers are not producing any sound, check that the large spool inductor is connected to the circuit board:



When you had the circuit board removed, were the black and white wires coming from the binding posts intact?

It is connected to the board, the wires were intact.

I'll check continuity later on today. I did hook a woofer straight into the amp and it did produce sound... that's why idk what the deal is... it must be something wrong with the crossover but idk what it could be because they worked perfectly when I got them............

although there was this one time I pulled an RCA from the back of the amp while it was on and the speaker was connected:( I felt so stupid after a did it.

westmassguy

You're going to have to start from scratch, from binding post, through the crossovers, and the wiring harnesses.

Mystery

A multimeter would be handy here to check the circuits.

Mr. Sharpe

will do.

Mr. Sharpe

I get no continuity between positive binding post and the wire going into the large inductor. the wire is going to the binding post but I'm sure somehow or another it could've come undone.

Mr. Sharpe

okay, after checking the other speaker there is copper exposed close to the glue I covered the back of the posts with, I have continuity there no problem, I scratched what feels like plastic insulation off of the other wire in the opposite speaker and could push on the wire and get a beep, after getting a couple of time the last time I pushed it (made for sure I was touching copper to binding post) it stopped beeping.... time to extend those inductor wires directly into the circuit board perhaps? the wires were connected to the binding post when I got the speakers.

westmassguy

You need to remove all the hot glue, and check those connections. The Inductor wire and the black wire are crimped together in a ring connector on later models, but early models were soldered rather poorly. Some were wrapped around the post, then a nut was installed and everything soldered in big mess. The white wire goes from the binding post directly to the circuit board.

Mr. Sharpe

that was it! I had to break the JB weld... kinda covered the backs of the binding posts with it lol. I could pull the inductor wire out so after breaking it up a little, obviously it wasn't soldered very well by me in the first place. but it works now, I still feel like the right channel (the speaker that was broken) sounds a little weak, but it could just be my hearing:( it does look like the tweeter in that speaker was replaced at some point, the sticker on the back looks pretty new and the allen key screws aren't rusty.... but why a newer tweeter would sound weak, hearing problem. they sound so much better than the CV's I had! like wow, I actually sold them a few days ago locally.

F1nut

Why would you put JB Weld on the backs of the binding posts? Use hot glue instead.

tonyb

F1nut wrote: »

Because sand cast resistors suck. Shop at Sonic Craft.

Really wish Jessie would stop beating around the bush and be more direct...lol.

TennMan

F1nut wrote: »

Why would you put JB Weld on the backs of the binding posts? Use hot glue instead.

Maybe the JB Weld was on there to keep the solder from falling off. lol

gimpod

Yea he dose kinda sugar coat things doesn't he.

westmassguy

Mr. Sharpe wrote: »

that was it! I had to break the JB weld... kinda covered the backs of the binding posts with it lol. I could pull the inductor wire out so after breaking it up a little, obviously it wasn't soldered very well by me in the first place. but it works now, I still feel like the right channel (the speaker that was broken) sounds a little weak, but it could just be my hearing:( it does look like the tweeter in that speaker was replaced at some point, the sticker on the back looks pretty new and the allen key screws aren't rusty.... but why a newer tweeter would sound weak, hearing problem. they sound so much better than the CV's I had! like wow, I actually sold them a few days ago locally.

Did you replace the binding posts?

Mr. Sharpe

Because JB weld is the bomb of course!

I had replaced the binding posts with some nice copper ones a good while back, just a little bit after getting the speakers.

I thought he fairly vague with the whole "they just suck" comment also. I'm going to post some pics of these, I know I didn't tell anyone that I changed the binding posts... neither have a showed ya'll a picture of my stereo stand I had custom built:)

Mr. Sharpe

Faustin

Why is there still a yellow Mexico cap on that crossover?

Simplyrandom

Faustin wrote: »

Why is there still a yellow Mexico cap on that crossover?

I was wondering the same thing..