Need help determining K-61-K driver polarity

[Serge_S]

How do I determine polarity in K-61-K squawker if there is no yellow mark and the terminals are of the same size.  There is something that looks like an "R" in white paint or marker by one of the terminals.   This is from Forte II of the 1990 vintage.  I am not changing the driver, just need to hook up Crites crossover and would like to avoid taking the driver apart if possible (there suppose to be a mark on the diaphragm). Thanks

 

Serge

Edited November 4, 2014 by Serge_S

[wvu80]

Do you know the 9v battery test?  I'm thinking it will also work with a D battery and a couple of speaker wires.  I don't know if this will work with a squawker.

 

Edit:  The more I think about it, there is probably no way this would work with a CD.  Sorry.  At least consider this post a free BUMP so someone smarter than me (just about everybody) will chime in and help you! 

 

Edited November 4, 2014 by wvu80

[mustang guy]

I'm gonna say R=red

 

Let me know if that turns out to be correct.

[Serge_S]

I'm gonna say R=red

 

Let me know if that turns out to be correct

 

Thanks.  Unfortunately, no way to tell without taking the driver apart.

[Serge_S]

Do you know the 9v battery test?  I'm thinking it will also work with a D battery and a couple of speaker wires.  I don't know if this will work with a squawker.

 

Edit:  The more I think about it, there is probably no way this would work with a CD.  Sorry.  At least consider this post a free BUMP so someone smarter than me (just about everybody) will chime in and help you! 

Thanks. There will probably be some movement of the diaphragm, but barely perceptible.  Not sure if it can damage midrange diaphragm or not.  And it would require taking the driver apart. I was hoping to avoid that step.

Edited November 4, 2014 by Serge_S

[WMcD]

Do you think the wiring is undisturbed from the original installation?  If so, we can reason backwards.

 

You can take a look at the thread with the crossover schematics.  https://community.klipsch.com/index.php?/topic/113804-klipsch-crossovers/

 

The schematic for the Forte II is there.  It does not show the color coding of the wires. But look down to the Chorus II which is the papa bear to the Forte II momma bear.  (The Quartet is the baby bear of the group.)  I'm quite sure the coding will be the same.

 

The midrange plus wire is yellow.  Which is where your photo shows the "R" is located.

 

I thought there was some traffic here on the board saying that R markings in hand lettering indicate refurbished or replaced or reworked.  But maybe that is not the whole story and it does indicate "red" which is very usually the plus.

 

For what it is worth, I see the tweeter is wired in reverse polarity according to the schematics.  So I'm thinking that its red wire is connected to the negative of the tweeter (kinda confusing and you can't tell for sure without a closer look and perhaps a continuity tester).  An ohm meter would indicate the tweeter red wire is zero ohms to the black for the two other drivers.  The black wire would be open at DC resistance check because of the capacitor feed.  Maybe you can look at your tweeter and see if it has an R also.  Or look at the mid in your other box and see what is there.

 

WMcD

Edited November 5, 2014 by William F. Gil McDermott

[Serge_S]

Thanks WMcD,

I took the driver apart without realizing that diaphragm is integrated into a phase plug and the “R” marking was actually on the visible surface of the phase plug.  So taking the driver apart didn’t help.  I did notice another marking near the same terminal where “R” is.  It’s a small circle with “PM” in it.  Does that indicate polarity?

Question about schematics.  I see there are 2 diagrams floating on this forum, the old one in the link you pasted and this one:

https://community.klipsch.com/index.php?/topic/87353-forte-ii-corrected-crossover-diagram/

I don’t read schematics, but from what I could guess looking at the corrected diagram midrange is not reversed.  The old schematic looks ambiguous to me.  If I cannot figure out the polarity from the markings on the driver, maybe I can figure it from how the old network was connected?

 

Serge

[Arash]

connect a battery to an Oscilloscope and see how it will reflex on the monitor. then connect the scope to your compression driver and to blow slowly into the throat to act as a microphone. if what you get on the monitor is relatively similar to what you got with a battery, then the lead connected to + prob of the scope should be + of the driver IMO

Edited November 6, 2014 by Arash

[mark1101]

For as long as I can remember Klipsch always marked the + terminal with a marker.  I have cornwalls and heresys with red marks.  I had Khorns with white marks like in the photo of the original post.

[mustang guy]

For as long as I can remember Klipsch always marked the + terminal with a marker.  I have cornwalls and heresys with red marks.  I had Khorns with white marks like in the photo of the original post.

As mentioned earlier, the Forte II network has the polarity reversed on the squaker. This might be why they indicated with white and with an R. The R indicates connect the red wire here even though it is actually the negative terminal.

 

If they would have used '+' or a red dot, then a person without the schematic or the ability to read it, might connect the driver backwards. A white 'R' is the perfect answer.

 

I speculate 'R' = negative, and it is where you will connect the POSITIVE wire.

 

It looks to me like there is a '-' (minus sign) in the plastic where the left part of the 'R' is. That would confirm my hypothesis.

 

edit: The Forte schematic shows the reverse polarity correctly. The Forte II schematic shows a dead short on the left of the 1.5uF cap. This is a misprint, I am sure. The feeder to that cap should come from the positive wire and end. The positive and negative wires should not be shorted together after that. See diagram notes:

Edited November 6, 2014 by mustang guy

[mark1101]

Bob Crites site says the + terminal is marked.  Go to his site and it shows step by step how to replace the diaphragm on the driver.

 

I also did a search on the network themselves.  You can find pics that show the wires on the squawker reversed on the network PC board.

 

What it looks like is that the + is marked.   The yellow wire goes to the +, black to the -.  The wires are then reversed on the PC board.  They are not connected backwards on the driver.

 

 

[mustang guy]

Here is a thread on the corrected Forte 2 network diagram. It seems the polarity is NOT reversed on the midhorn.

 

Forte-II corrected crossover diagram

 

The only way I know of with 100% accuracy to get this driver connected right is to replace the diaphram with one that is marked +/-.

[mark1101]

Are these the crossovers?  Notice how the mid range wires (yellow/black) are reversed on the PC board.

 

 

[mustang guy]

picture too small mark...

[Arash]

to not speak theoretically, I tested this method and it works. I was able to distinguish + and - of the CD. DUT was a Denovo DNA-360 I had idle lying around. we know if the polarity of a CD is right, the diagram will push upward so the pressure at the throat increases, if the polarity is inverse, it will move downward so sucks in the air. I used some non-iron washer as spacer:

 

 

I put them on a very thin selephone sheet:

 

 

I put the spacers on the selephone:

 

 

then put the CD on them and wrap the plastic all around the driver:

 

 

the plastic layer will be in some kind of suspension so any movement in or out will be simply visible:

 

 

I connected a 3v battery to the compression driver. when the + of the battery is connected to + of the CD and - to -, the plastic pushes out, when is polarity is reverse it will be sucked in.

I hope this helps.

 

 

 

[Serge_S]

Thanks Arash. This is a great test, but I am not sure if I can perform it with this diaphragm.  I am reluctant to attach anything to the windings.

 

 

Edited November 7, 2014 by Serge_S

[Serge_S]

Bob Crites site says the + terminal is marked.  Go to his site and it shows step by step how to replace the diaphragm on the driver.

 

I also did a search on the network themselves.  You can find pics that show the wires on the squawker reversed on the network PC board.

 

What it looks like is that the + is marked.   The yellow wire goes to the +, black to the -.  The wires are then reversed on the PC board.  They are not connected backwards on the driver.

Thanks Mark.  Bob's site reports different marking from the one I have.  It's yellow dot.

 

I tend to agree that wires are reversed on the PC board only.  If so, looking at the marking on the board I have both highs and mids reversed.

Edited November 7, 2014 by Serge_S

[Serge_S]

Are these the crossovers?  Notice how the mid range wires (yellow/black) are reversed on the PC board.

these are the ones

[Serge_S]

The only way I know of with 100% accuracy to get this driver connected right is to replace the diaphram with one that is marked +/-.

 

 

Thanks. I've been thinking about exactly this for the past few days.  Pity.  My drivers are in great condition.

[Serge_S]

 

For as long as I can remember Klipsch always marked the + terminal with a marker.  I have cornwalls and heresys with red marks.  I had Khorns with white marks like in the photo of the original post.

As mentioned earlier, the Forte II network has the polarity reversed on the squaker. This might be why they indicated with white and with an R. The R indicates connect the red wire here even though it is actually the negative terminal.

 

If they would have used '+' or a red dot, then a person without the schematic or the ability to read it, might connect the driver backwards. A white 'R' is the perfect answer.

 

I speculate 'R' = negative, and it is where you will connect the POSITIVE wire.

 

It looks to me like there is a '-' (minus sign) in the plastic where the left part of the 'R' is. That would confirm my hypothesis.

 

edit: The Forte schematic shows the reverse polarity correctly. The Forte II schematic shows a dead short on the left of the 1.5uF cap. This is a misprint, I am sure. The feeder to that cap should come from the positive wire and end. The positive and negative wires should not be shorted together after that. See diagram notes:

 

 

If R is negative, than mids connect from reversed at the board to negative on the driver which would mean polarity is not reversed.

 

What looks like the '-'(minus sign) is metal terminal reflecting in the plastic.

Edited November 7, 2014 by Serge_S