JPW Mini Monitor - Decent!

[Craig B]

I have a pair of white JPW Mini Monitors that worked like a charm for years. Out of the blue one of them went dead silent. I have done all the rudimentary troubleshooting (switching cables, different amp, switching left and right), and it’s clear one of them is not working. I cannot see any visible damage and all the soldered connections look fine.

Could anyone please provide some guidance regarding troubleshooting the internals? I have a multimeter but I have never done this before. Thank you!

It is unusual for a 2-way loudspeaker to go dead silent, as opposed to no treble (common) or no bass (less common). Unless seriously abused, dead silence is often down to something less serious than blown, and possibly difficult to source, drivers. Could be as simple as a cold solder joint on either the +ve or -ve binding post connections within; something that can arise should one post be loose and free to turn whilst tightening the nut, for example.

Suggest you start by removing the terminal block from the back panel, as this has the crossover components attached and, therefore, will allow testing of terminals, crossover, wiring, and drivers all without having to remove the drivers from the enclosure. No need to cut any wires, just leave the terminal block hanging out the back.

In the meantime, I have some Mini Monitor crossover photos to share that can be marked up to show what test points and settings to use with the multimeter.

 

[originsprogram]

I had a factory made JPW Gold surround system as my first cinema system when I was a young 20 something. It also had a passive subwoofer with a pair of 8’s in a three chamber box - it was a great system - bearing in mind it was running a VHS front end back then! DVD didn’t yet exist!

Does the cone move on your broken JPW? if it does and your not getting anything out of it, it’s almost certainly a connection inside.. the crossover isn’t complicated - post a pic maybe??

The cone can move freely when I push it gently! I'm not allowed to post pictures here because of spam flag? I will message you a link.

 

[originsprogram]

It is unusual for a 2-way loudspeaker to go dead silent, as opposed to no treble (common) or no bass (less common). Unless seriously abused, dead silence is often down to something less serious than blown, and possibly difficult to source, drivers. Could be as simple as a cold solder joint on either the +ve or -ve binding post connections within; something that can arise should one post be loose and free to turn whilst tightening the nut, for example.

Suggest you start by removing the terminal block from the back panel, as this has the crossover components attached and, therefore, will allow testing of terminals, crossover, wiring, and drivers all without having to remove the drivers from the enclosure. No need to cut any wires, just leave the terminal block hanging out the back.

In the meantime, I have some Mini Monitor crossover photos to share that can be marked up to show what test points and settings to use with the multimeter.

Thank you Craig. I don't know how to determine if the drivers are blown or not but the cones can move freely upon manually pushing gently.

I would love to see your pictures for troubleshooting!

 

[Tumeni Notes]

I have two pairs - one standard, one Gold variant, both in the garage waiting for me to put one pair (still to pick which) on shelves and make a garage audio system out of them.

 

[eevo1969]

Good friend of mine picked up a JPW surround sound pack, 4 mini monitors and a subwoofer, suffice to say the subwoofer wasn’t great.

 

[Mike Reed]

I've had Golds for years; used to be in my kitchen receiver system but replaced by much clearer and bigger Gales (Richer Sounds). I also picked up a pair of TDL Nucleus 1s a few years ago (charity shop) which are the same size and format (I.B.s) and oddly, sound about the same as the JPWs, albeit marginally more sonically distinct.

 

[stevec67]

Thank you Craig. I don't know how to determine if the drivers are blown or not but the cones can move freely upon manually pushing gently.

I would love to see your pictures for troubleshooting!

A small battery can be used to good effect to test woofers, get a 9V one, connect it direct to the terminals. If good, the woofer will go "thud". DO NOT do this with the tweeter, tweeters will blow if exposed to DC and this is filtered out by the cross over. My money is as Craig says, a break between the terminals on the rear and the cross over. You have swapped speakers I take it and confirmed that it is a speaker and not a dead channel on an amp or a bad connection on a speaker cable?

 

[Tumeni Notes]

I don't know how to determine if the drivers are blown or not

Rough n ready method Take the panel off back, identify the cables which lead from crossover to drivers, and, using a 1.5v battery and some spare bits of wire, attach negative to one of the driver wires with a crocodile clip or similar, and flick positive wire against the other to make momentary contact. Clicking noise from driver indicates driver OK.

 

[Craig B]

Thank you Craig. I don't know how to determine if the drivers are blown or not but the cones can move freely upon manually pushing gently.

I would love to see your pictures for troubleshooting!

You are welcome.

You mentioned having a multimeter, therefore, testing can be a bit more precise than a battery test of raw bass/mid driver.

Using the photo below as reference, with meter set to Ω, touch the probes to the points indicated by the red arrows for bass/mid driver and record the reading (probe polarity isn't important). Then repeat for tweeter via the points indicated by the blue arrows. These points bypass input terminals and crossover. Once 'we' have established whether the drivers be healthy or no, I'll post up a photo of terminals / crossover test points.

IOW, a process of elimination starting with worst case scenario (e.g. blown drivers) and proceeding backward to best case scenario (e.g. a bad joint at either of the +ve or -ve terminal tabs).

These tweeters usually measure circa 6.5Ω, so that is roughly what you should get across where the blue arrows point. The loudspeaker system is rated at a nominal 6Ω, but that includes the crossover network. Regardless, the bass/mid driver (red arrow test points) is likely to read in the vicinity of 6Ω as well.

 

[Tim Jones]

Can you still buy Camp Coffee?

Moving on...You can pick up a pair of Mini Monitors on the Bay for about £30 usually. Ridiculously good vfm.

You can, and it's nothing like as good as I remember it ..

I found a pair of JPW Minims in a skip outside my flat in Kingston four years ago. Put them back though as had no stands for them, and they wouldn't have stood a chance in my massive old room

 

[originsprogram]

You are welcome.

You mentioned having a multimeter, therefore, testing can be a bit more precise than a battery test of raw bass/mid driver.

Using the photo below as reference, with meter set to Ω, touch the probes to the points indicated by the red arrows for bass/mid driver and record the reading (probe polarity isn't important). Then repeat for tweeter via the points indicated by the blue arrows. These points bypass input terminals and crossover. Once 'we' have established whether the drivers be healthy or no, I'll post up a photo of terminals / crossover test points.

IOW, a process of elimination starting with worst case scenario (e.g. blown drivers) and proceeding backward to best case scenario (e.g. a bad joint at either of the +ve or -ve terminal tabs).

These tweeters usually measure circa 6.5Ω, so that is roughly what you should get across where the blue arrows point. The loudspeaker system is rated at a nominal 6Ω, but that includes the crossover network. Regardless, the bass/mid driver (red arrow test points) is likely to read in the vicinity of 6Ω as well.

After having conducted testing according to your guide my conclusion is blown tweeter.

Bass driver impedance ~ 5 Ohm
Tweeter impedance either zero or sky high (in the megaohm region)

What’s strange though is that it didn’t produce any sound what so ever upon function test.

I will have someone more qualified take a deeper look this weekend. Meanwhile I will pick up a pair of P1s instead

Thank you again Craig, what a warm welcome I received entering this forum. Happy Friday

 

[Craig B]

After having conducted testing according to your guide my conclusion is blown tweeter.

Bass driver impedance ~ 5 Ohm
Tweeter impedance either zero or sky high (in the megaohm region)

What’s strange though is that it didn’t produce any sound what so ever upon function test.

I will have someone more qualified take a deeper look this weekend. Meanwhile I will pick up a pair of P1s instead

Thank you again Craig, what a warm welcome I received entering this forum. Happy Friday

With the tweeter measuring into the megaohm region, the amplifiers output will be shorted on that channel.

eBay.co.uk to the rescue. Tweeter driver bayonet mounts into the rectangular faceplate from behind. This one measures good.

JPW Mini Monitor - Genuine Replacement Tweeter Unit - Fully Working | eBay

<p>JPW Mini Monitor - Genuine Replacement Tweeter Unit - Fully Working.</p><p>Fully working and in excellent condition.</p><p>Resistance shown on the multimeter.</p><p>Comes as the item only, as shown, no further items. </p><p>Please see all photos of the exact item/s for sale. </p>

www.ebay.co.uk

 

[Craig B]

Hold the bus! Here is a NOS pair of the same Audax TW010F1 based rectangular faceplate tweeters from a business in Bristol. Confusingly, they are listed as a pair but the seller is showing different prices for 'Buy 1' £12.99 each, 'Buy 2' £11.69 each, 'Buy 3' £11.04 each, or '4 or more' for £10.39 each.

Pair of JPW 1" Rectangle Dome Tweeter 8 Ohm Capable of 70W | eBay

Suitable for most mid range cabinets, these are capable for upto 70w at 8ohms.

www.ebay.co.uk

 

[Craig B]

Pardon my ignorance. Does the TW010 also contain ferrofluid?

S.

A bit late, but, yes, there were a few variants of TW010 and all were ferrofluid cooled.

IME, if these have been left unused for some time, they typically only need a day of hard running in order to come back on level. I've always assumed that the fluid, having become more viscous, leads to increased mechanical resistance, which in turn causes greater heating of the fluid, somewhat restoring the viscosity. Of course, this assumes that they are not glued shut in the first place.