testing a crossover

likklegerry - Just forget that question, I already understand. Providing your crossover passed the test using the diode mode at the mid/high bi-amp inputs, which it appears to have. I think you are good to go. Just perform that same test with the drivers connected. I'll get back in touch later today.

pragmasi- 1) Original test with everything assembled showed 0Ω resistance across the MF/HF +/- terminals on the back of the speaker.
2) Those terminals connect directly to IP+ and IP- on the crossover PCB.
3) With the crossover disconnected the DC resistance between IP+ and IP- was open circuit.
If points 1-3 are correct and you’ve put it back together and measured 0Ω across the loudspeaker terminals then there’s a short somewhere between the terminals and where the wires connect to IP+ and IP-.

totally correct

4) With everything disconnected from the crossover you measured the resistance across the copper you have marked M+ and M- and got 0Ω.
                                   -not sure where i said that-
                                       No it reads 2.7ohms
hope that helps.
Mk

Pragmasi-im really sorry,but there are no open circuits

Absolutely nothing to be sorry about at all... would just be good if we could help you fix this.

shorting links on speaker binding post havent ever been used,to go from bi-wire to normal two wire

Shame... thought I was onto something there... how do you connect the terminals when running from one amplifier?

It'd be useful if you could describe where you're measuring the short circuits using the references you've added to the PCB with a sharpie.

Would be great if we could all help you get to the bottom of this.

fiesta-"  an ohm meter test between the HF+ and LF+ terminals should be 0.0 ohms. Same should be true of the HF- and LF- terminals. This can be measure at the speaker or amplifier terminals."
measurements for above,taken on the x-over 
both OL ,ohms

shorting links on speaker binding post havent ever been used,to go from bi-wire to normal two wire ,or bi-amp to normal two wire config

ps was that pragmasi or eric which posted the equation post ? 

Pragmasi-im really sorry,but there are no open circuits, i have closed circuits{shorts},which are the problem,surely if i have a short internal of the x-over ,before it reaches the mid and high drivers this will draw current.to be honest,i thought i knew how to test a speaker box,it seems im totally out of my depth here,which i knew,but was just asking for basic help,101 style,im no way an electronics engineer ,hobbist at most,not even that,so giving me eqations to do ,when i dont even know what the sybol mean ,is a strtch too far,its like me asking to to calculate the dwell angle and timing on a camshaft for a super charged car,if you dont know,it will take a long time to learn,i have one simple question why does the mid/high on the crossover have a short within the x-over,when the bass driver does not,im just not grasping even that,and how come there is not an ohms reading for the mid/high at the binding posts,please please excuse my ignorants,
mk

erik - If you are not really going to try and help, stay out of it! Dude...

@erik_squires 

Dude, you should have followed my advice and you'd be done by now. :)

The best way I know of to test a crossover is to generate an impedance graph. You can use DATS V2 (or is it now up to V3) or you can build a jig and use Room EQ Wizard’s app for this.

How is that advice?.. it's not going to help anyone who doesn't already know what they're doing.

Dude, you should have followed my advice and you'd be done by now. :)

pragmasi - I assume your post above was meant for me? I guess I really didn't need an answer to the last 2 sentences of my above post because I'm sure the answer is really yes, and maybe confusing to some.
You are absolutely correct about forgetting the jumpers when switching from bi-wiring to bi-amping. That could easily blow one or both amps used in a bi-amp configuration.

between the HF+ and LF+ terminals should be 0.0 ohms

do you mean open circuit?.. Not being snarky, just checking :-).

You have made me think of something though... if you forgot to take the shorting plate/wires off the loudspeaker posts when switching to a bi-amp config you could get enough current flowing between the two amplifiers to blow one of them.

likklegerry - Thanks for your test data, looks like everything except the Lo and Hi bi-wire connections are in line with what I expected. Just to be clear, with the amplifier and other electronics off, an ohm meter test between the HF+ and LF+ terminals should be 0.0 ohms. Same should be true of the HF- and LF- terminals. This can be measure at the speaker or amplifier terminals.
The diode mode tests at the HF and LF connectors also show what I was expecting.
The dc resistance measurements with the drivers disconnected are in line of what is expected too. Don't worry if it's mH or not, trust us, it is mH.
Which capacitors (value) is showing shorted in the diode mode? The caps themselves should be tested in the ohm mode. I will continue reading an ask questions or make comments as needed.
Please do the resistance test between the HF and LF terminals as described above. This is in the bi-wire configuration with all wires connected to one amplifier.

Okay... I think I am having trouble following. Also there might be a bit of confusion around resistance (DC) and impedance (AC). When you read the resistance across the loudspeaker terminals it has very little to do with the nominal impedance of the speakers (this is even true if you measure across the driver itself). You have a high pass filter on both the mid (12µF) and the tweeter (4.2µF) so if everything is working correctly you should get an open circuit when you attempt to measure resistance across the loudspeaker posts with everything connected.

I’ll tell you what I think I’ve understood and you put me right if I’ve misunderstood:

1) Original test with everything assembled showed 0Ω resistance across the MF/HF +/- terminals on the back of the speaker.
2) Those terminals connect directly to IP+ and IP- on the crossover PCB.
3) With the crossover disconnected the DC resistance between IP+ and IP- was open circuit.
If points 1-3 are correct and you’ve put it back together and measured 0Ω across the loudspeaker terminals then there’s a short somewhere between the terminals and where the wires connect to IP+ and IP-.

4) With everything disconnected from the crossover you measured the resistance across the copper you have marked M+ and M- and got 0Ω.
5) According to the schematic M+ and M- should be connected (at DC) via 2.5µH inductor (of negligible DC resistance) and a 2.2Ω resistor.
6) On your most recent test you measured 2.7Ω.
If point 4 was true then you’d most certainly have overloaded your amp and would have got no sound from the driver... however the most recent measurement shows no such problem.

i think we may have a misunderstanding some times about ,when i use a diode test and ohms test,i think i haven't explained it well enough,or used the wrong test for finding this fault
originally when i tested the speakers{in the beginning}there was NO reading on ohms for the test when testing the mid/hi speakers on the terminal speaker posts on the back of the speakers,
please see first tests
"          LEFT SPEAKER                                  /
 RIGHT SPEAKER
                speaker terminals with everything connected on both speakers

     MID/HIGH        0.0 ohms                             /
    MID/HIGH    0.0 ohms
       BASS           7.9 Ohms                             /
       bass          6.8Ohms

                                      DRIVER TEST DISCONNECTED FROM X OVER
          TWEETER 8 OHMS                                 /
    7.9 OHMS
              MID 6.3 OHMS                                   /
         6.2 OHMS
             BASS  6.1 OHMS                                /
       6.0 OHMS

     CONTINUITY TEST ON X-OVER WITH DRIVERS REMOVED USING DIODE FUNCTION
                                             between positive and
negative on x over
         HF                  000.2 {dead short}
         /       000.2 {dead short}
         MF                  000.5
              /       000.5
         LF                     OL.
                /        OL.
MID HIGH INPUT IP     OL.                                 /
                OL.
   BASS INPUT            OL.                                 /
                   OL.
                                                  OL. BEING NO CONTINUITY

                               TEST TESTED AT/ON X-OVER SPEAKERS CONNECTED OHMS

         HF 0.0002 OHMS                                      /
              0.002 OHMS
         MF 0.0001 OHMS                                      /
               2.0 OHMS
         LF   6.4 OHMS                                          /
                   6.3 OHMS
what i see,is that when testing a speaker from the speaker cable posts,disconnecting from the amp,i should see how many ohms the speakers are,in this case they are 8 ohms speakers,and i have tested them on other ocassions,after re-wiring them once another time when i re-capped them,just as a check for shorts or problems and they have always read in the ball park of between 7.8ohms and 8ohms,for both bass and mid/hi ,now it doesnt read that,the bass is ok but the mid/high reads 0.0ohms,i only checked them,when my technican asked me to after the first time he repaired the ampand it blew,and sure enough there was a problem,does this throw any light on what your thinking,or have i really badly explained the problem,really sorry if i have.
regards
MK

between mid pos and neg 2.7 ohms

Okay... before you said that you were getting 0Ω across the MF +/- outputs with the driver disconnected. Is this the same measurement? If it is then it's close enough not to worry about for this exercise. As imhififan said:

The MF measurement should equal to the DC resistance of the 2.5mH inductor + 2.2Ω.".

Take into account there's a bit of tolerance on those resistors as well as the accuracy of your meter.

Not sure what 0.22mH is and also 2.5mH inductor +2.2 ohms,i know what the inductors are but not sure on mH.

Although the inductors will have some DC resistance you can pretty much ignore it for the purposes of this excercise as long as you're in the ball park of the resistor values.

Also i have found that one of the capacitors has a dead short short when tested in dioode mode,{still soldered into pcb},on both x-overs, when the rest show OL,not sure if that has a bearing on anything, just throwing it out there.

If that's the 6µF cap then the reading is correct as it's in parallel with the 2.5µH inductor which will have very low resistance at DC.

If I've understood you correctly then the tests don't seem to have turned up any results that would cause the amplifier to fail.
Maybe someone else will spot something I've missed... or maybe the tech didn't find the real fault in the amp when it was sent in the first time.

further to reply to imhififan1 im not sure how to test for what your asking 
" Without drivers connected,
The HF measurement should equal to the DC resistance of the 0.22mH inductor.
The MF measurement should equal to the DC resistance of the 2.5mH inductor + 2.2Ω.".
Not sure what 0.22mH is and also 2.5mH inductor +2.2 ohms,i know what the inductors are but not sure on mH.
Also i have found that one of the capacitors has a dead short short when tested in dioode mode,{still soldered into pcb},on both x-overs, when the rest show OL,not sure if that has a bearing on anything, just throwing it out there.
Any guys sorry again for the late reply,i hope your all still speaking to me, thankyou again for all your help.
Kind regards
Mk
ps i have posted some more pic of cap showing short and the resistor ive tested
thx again MK

Hi guys, sorry for the very late reply in my/your quest to sort this out,ive done a couple of thing since, taken advice on multi meter/s, fitting fully charged battery's in the digital and analogue multi meters,both tested by using an 8ohm resistor, I use for running in component/gear, just incase, removed all wire to and from the x over and cleaned the board,and flowed every joint,so there no chance of dry joints and shorts,also i have done a continuity test from every component lead to pcb tracks,all joint good, please find results of questions asked.
multi meter set to ohms-
between mid pos and neg  2.7 ohms
between tw   pos and neg  0.002 ohms
mid/high inputs  OL {held on for 5 secs}nothing changes
mid/high inputs {reversed} OL{held on for 5 secs}nothing changes
when run with one amp,in bi-wire mode both pos are NOT connected the same goes for the neg wires,the amp has 2 sets of switched speakers terminals,i use one set for the bass and the other set for the mid/high,so the two speaker cables do not touch each other 
resistor showing short{5w2R2J},which i measured using continuity mode,just above IP neg,when doing an ohms test is reads 2.3ohms

Diode test on mid/high -OL
when reversed is flashes 2.2xx,then goes to OL
every time i reverse leads it flashes something {2.2xx}not sure its voltage,it doesnt tell me that

You can find all the photos here

https://systems.audiogon.com/

Without drivers connected,
The HF measurement should equal to the DC resistance of the 0.22mH inductor.
The MF measurement should equal to the DC resistance of the 2.5mH inductor + 2.2Ω.

CORRECTION, sorry. The last test on the mid/hi amp terminals on the crossover board; when I asked to to test and then reverse the meter leads and test again. The multimeter should be set on the "diode" test mode, not ohms. The readout should display some voltage then go to OL. When you immediately reverse the leads, the display should read -x.xxx volts, then change to +x.xxx volts before going to OL. Hope your meter has a diode test function, but it's not absolutely necessary. This test just shows that the caps are charging in both directions.
I still can't explain why the system worked with one amp when the mid/high amp was in repair... This is troubling. 

Which resistor, if it's STILL showing a dead short or 0.00 ohms? This is the one mentioned in post 6-16 @ 12:59am

Okay, its been a rough couple days. I just got done drawing the schematic and looking at the words and measurements again. Just one note, do all measurement in the resistance mode, not in the diode mode as the diode mode really doesn't tell us anything. You don't need to disconnect one end of the resistors to check each resistor. So with no drivers attached, between the midrange terminals on the crossover board, you get close to 2.2 ohms, but it's not a dead short correct? For the tweeter terminals, you get close to 0 ohms, but not a dead short correct? At the mid/hi amp inputs, you get essentially OL after holding the probes on the terminals for few seconds, correct? What happens when you reverse the leads on the mid/hi amp terminals? Does the meter go to (-) xxx.x ohms then to (+) xxx.x ohms before going to OL? This is a dumb question, but just so I understand everything. When you use only one amplifier to power the speaker in the full range (bi-WIRE) mode, the (+) terminals of the inputs are connected together. And separately, the (-) terminals of the inputs are connected together, correct? The photos are gone, but don't think we need it again. From your DC voltage measurements at the amps, they look healthy. Please answer all of my questions in order, so we don't get confused, thanks.

mid speaker cable going to driver,dead short.no driver connected

Actually looking again you should be getting around 2.2Ω across the Mid driver outputs. I'd look at the photos again, but they're not there any more. The area to inspect is the bottom half of the board when orientated like the schematic.

resistance between IP POS And IP neg  -OL

Okay, so that checks out... as long as when you put the whole lot back together you still get open circuit at DC across the HF/Mid posts all is as it should be and there's no DC load on your amp.

Hi Guys,sorry for the late reply, my wife doesn't see my urgency about this,so im going with the flow!!,please bear with me.
So,i now sat here with one of the crossovers multi meter in hand and i will try answer al the questions
DC offset,taken at speaker cable end ,speaker removed
repaired amp mid/high left chan 0.000 right chan 0.001v {DC]
bass amp                     Left chan 0.006 Right chan 0.002 {DC]
on xo IP pos and IP neg have good solder joint{tested good}
resistance between IP POS And IP neg   -OL ,
Multi meter checks out good,i have two of them ,both reading close enough.
No visabe shorts on board or speaker terminal board
mid speaker cable going to driver,dead short.no driver connected
tweeter spaker cable going to driver ,dead short, no driver connected
bass cable going to driver. OL,   no driver connected
ALL 3 OF THESE TESTS WERE ALSO TAKEN FOR XO PCB END
internal speaker cable from input to xo,No shorts

Test for shorts done at speaker cable imput {4 terminals}for bi-wire and Bi amp,inputs at the back of speaker boxes,   NO shorts 
to test resistors do i need to remove one side from pcb xo,ive just tested one [5w2R2J] and it showing a short,still fully soldered ??.
on the comments about capacitor placing on top of resistors etc,i do see what you mean,it was my first time replacing the caps on an xo and the leads where short,but i can remove the all and try again,its just that these caps are a lot bigger than was what installed at factory,sorry for my rubbish placement.
so all in ,i see no physical short, wires touching, all soldering has been tested for contin.all good,no dry joints,no cable fraying,no cable rub throughs,from vibration,it seem to me listening to you guys i maybe need to remove all components and test them,would i be wright in that assumption 
,hope the wife doesnt mind me spending the next day or two doing this !!!,shes wanting a  garage built !!!.
Anyway guys,i hope ive answered all you questions,i sure do appreciated you all taking the time out to help me with this,.
Kind regards
Mark
PS,im still open to tri-amping if you think it might be a better solution ,in the end,fiesta,but would be great to find the problem first,Anyway
cheers guys

The mid xover is a bandpass network and tweeter is high pass network which means if you measure the resistance, it should read "infinite resistance" or something very high.  It's interesting that both left and right channel all read 0ohm.

As for the woofer, it is a low pass network so it makes sense if you measure about 7ohm which is probably resistance of the driver voice coil and the inductor.

pragmasi - Yes, sorry for being an SA. You are absolutely correct, one needs to take one step at a time. I'm waiting to see and help if possible.

I can guess, but that would be uncalled for and premature

Is that in response to me?.. don't know what you mean. Only point I was trying to make is if you change lots of things at the same time sometimes it's difficult to know what the original problem was and so you learn nothing along the way.

I can guess, but that would be uncalled for and premature.

Yup, I don't disagree and that's good advice. I'm mainly interested to see what the cause is... it's a weird one.

I just looked at the crossover too, not good. Would be very easy to create a disastrous mistake, not to mention the EMI and RFI problems. Heat is not a friend of caps as you know.

@fiesta75 and pragmasi,
IMO, the layout of components is not ideal, especially those capacitors that seat on top of resistors! since he is at it, I think it's time to fix that...

pragmasi - I agree, rule out the simplest possible problems first. That's why asked about cables and connectors. Did we ever get an answer about that? I'm going to look at the schematic now. Good luck!

fiesta75 and imhififan are on the money with their advice... but I'd hold fire with the soldering iron until you've got a little more to go on.
IP+ and IP- should be open circuit at DC (OL), although you may need to leave the probes in place a few seconds while the caps charge.
If you're still getting 0Ω across IP+ & IP- then it's most likely a short somewhere between the input terminals and the copper pours that sit directly under IP+ & IP- on the PCB, you should be able to check this visually.
If that doesn't turn up anything then it might be time to reach for the iron.

Hi Guys,thankyou so much for all your help,but i still dont see a solution to this problem,in my opinion there is shorts in both xos,please see below-

LEFT SPEAKER / RIGHT SPEAKER
speaker terminals with everything connected on both speakers

MID/HIGH 0.0 ohms /
MID/HIGH 0.0 ohms
BASS 7.9 Ohms /
bass 6.8 Ohms

Please disconnect the wires from binding post and measure the MID/HIGH resistance again across IP+ and IP- to rule out the short is not from the binding posts.

DRIVER TEST DISCONNECTED FROM X OVER
TWEETER 8 OHMS / 7.9 OHMS
MID 6.3 OHMS / 6.2 OHMS
BASS 6.1 OHMS / 6.0 OHMS

CONTINUITY TEST ON X-OVER WITH DRIVERS REMOVED USING DIODE FUNCTION
between positive and negative on x over
HF 000.2 {dead short} / 000.2 {dead short}
MF 000.5 / 000.5
LF OL. / OL.
MID HIGH INPUT IP OL. / OL.
BASS INPUT OL. / OL.

OL. BEING NO CONTINUITY

The above measurement of MID HIGH INPUT IP looks OK,

TEST TESTED AT/ON X-OVER SPEAKERS CONNECTED OHMS
HF 0.0002 OHMS / 0.002 OHMS
MF 0.0001 OHMS / 2.0 OHMS
LF 6.4 OHMS / 6.3 OHMS

The HF measurement should equal to the DC resistance of the 0.22mH inductor.
The MF measurement should equal to the DC resistance of the 2.5mH inductor + 2.2Ω.

My suggestion is desolder all components from PCB, clean up the PCB, measure all components before re-install to PCB, leave some gap between resistor and capacitor to avoid heat damage those capacitors.

thankyou all again for this help,i uploaded a schematic of the crossover wilmslow have now sent me,i will test and check all readings and offset dc today,then i will get back to you all.
so many thanks
regards
mark

For some reason I can't access your crossover photos I saw yesterday. Anyone else have this problem?

Well if you have lifted one lead of each cap and they test good, I would say it's a short on the PCB. Check all the resistors just to be safe, most resistors open or go high when they fail. In one picture I saw a couple capacitor leads that looked very close together. On another note, you said the amp worked for about 3 hours when you first got it back. So I'm assuming they sounded good when bi-amped before it went pop? I'm thinking there could be physical contact between a couple components lead wires. Reason, it work for a while. Maybe vibration caused the components to get physically close enough to short. What is the value of the cap connected to the midranges in the bi-amp configuration?

No NOT ac voltage, DC voltage. This is the offset voltage of the amp and I wanted to make sure they were low as THAT could be a cause of capacitor failure.

Are you measuring the resistance across IP- and IP+ on the PCB? It looks to me like IP+ routes to two resistors (2.2Ω and 3.3Ω), there's lots of clearance between the tracks and no obvious short. So even if there were a problem further down the line you'd expect to see at least 1.3Ω across the inputs. It's rare for resistors to fail closed circuit so I wouldn't go looking there just yet.
The 2.2Ω is in series with the 12µ cap which will block DC, I can't work out what the 3.3Ω connects to under that big cap, but I still can't see how there'd be 0Ω across IP- & IP+. I'm sure I'm missing something.
I can see fibres on the PCB conductors but assume they're hot glue or stuffing material. Even so I'd start by cleaning up the copper connected to IP- & IP+ and measuring the resistance across those if you haven't done so already. I'd also check the multimeter by measuring a known value e.g. a resistor that's out of circuit. You wouldn't believe the number hours I've wasted going down a rabbit hole only to find I've measured something wrong or missed something obvious.

I'm sure you'll get there in the end with the help of some others here... good luck.

OK,lets have a go with this,i have asked wilmlow for adivice ,schems and any help they can give me,but they just say send it in to us,and are not coming foreward with any other help,which is a shame,as these speakers were not cheap,for me anyway..
ive checked the AC voltage on both amps
amp driving mid/high which has popped twice, now repaired but running in another system {all good}
readings left channel -0.001v {AC]   right channel -0.001v {AC]
good amp[never popped} runs bass, left channel 0.002v [AC]
                                                            right chan.  0.002v AC
all other components turned off, except amps 
At this point i should add a little more history,after i got the amp repaired and plugged it back into the system,after about 3 hours it went pop again,so i sent it back to the technican,after ttwo days of him looking at it,he sent me an email asking me to checked my speakers,which is when i realised that was where the problem was,so i dont think it is either amps,i now run the repaired amp in another system which seems to be good,so i think the problem is in the crossovers,as all driver read the correct-ish ohms,but what i find very strange,is that both xo s have gone us,this is a puzzle to me.
I am totaly open to any options,but as a retired guy,money is a factor,but would love to find out the fault,but if its easier,i have another two power amps in boxes,but there are lower in power {Arcam Alpha 9p s}.
Another question ,is it not AC at the speaker terminals ?,im not sure!!
I have removed the caps from one crossover{or one lead} and they check out to be ok on all caps,
What do you think maybe  suspect on the wiring,or is it just my soldering ?.
ANYWAY I THANK YOU SO MUCH FOR ANY HELP 
regards Mark
PS if you can give me a day to work out a schem.that would be great.
Mk

ill try draw a schem.but its difficult, but ill do my best

@ likklegerry,
If you can print-out the crossover pcb photo and add all the component position on it with wiring and post the picture, maybe we can figure out the schematic and go from there.

 https://www.wilmslowaudio.co.uk/ekmps/shops/wilmslow/images/crossover-pcb-452-p.jpg

an example:

https://ibb.co/3zyQRyG

The reason why the speakers work with a single amp and not when bi-amped is because the crossover is using different sets of inductors and capacitors. When the speakers are bi-amped you are using one set of inductors and capacitors, those are the caps or wiring that has the problem. The inductors are not the issue in my opinion. The wiring is suspect, if the caps test good. Think about what I've said thus far and tomorrow we'll get into the testing if you insist on repairing these crossovers. At this point, I don't think it's necessary for you to measure the DC at the amplifier outputs although that is always good info.

Did you change all of the capacitors yourself? The caps look like they are good quality.

I just looked at all of your crossover photos. Don't take the following comments the wrong way, but this is my honest opinion. You should take those crossovers out and tri-amp with an active electronic crossover, please. You will truly be amazed at the improvement in sound you will get. Those are pretty cheap crossovers as the inductors are wound on ferrite and should be "air wound" on bobbins. The wire they are using for the inductors is Way to small and likely sucking allot of power from the drivers. This was a cost cutting decision when they were designed. No matter what you decide, I will help you get your speakers up and running again, bi-amped or tri-amped, whatever you decide. I'm going to take a close look at the measurements you posted the other day and all the pictures again. Will come back with questions and probably additional tests to perform. Did you ever measure the DC voltage at the amplifiers outputs with nothing connected and no signal input? Did you get the damaged amp back repaired yet? 

imhififan1,thankyou for that.
regards
mk

OK,IVE MANAGED TO SAVE THE PICTURES,but i am now strugling to put them on this page,im so useless !!,
regards
mark

im trying to upload photos,but it keep coming up with 
" Title has already been used on one of your systems."
I DONT UNDERSTAND WHY ?
REGARDS
MARK

Thanks imhififan, I didn't know that either. One other thing I thought you should check on both amps, both channels. How much DC voltage is present at the output terminals?