Repair ZP120


The amp has no power. Is there an internal fuse for this unit?

Has anyone taken one apart?

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Update: removed almost all diodes from underside op primary side. Theyre all Good. Something I noticed is that all the 5 points of this winding in the secondary side are shorted together, is this right? 

 

The secondary winding has two separate coils.  The first is across three pins with a centre tap.  Within each coil (the first 3, or the second two pins), you should measure a very tiny resistance (under 1 ohm) between the pins -- this is normal for a transformer.  The short between the two coils is not normal.  You may have a short between the two secondary coils, or it could be ‘downstream’ of that.

I’ve fixed dozens of these devices and haven’t seen this particular problem before.  You can try to remove the transformer and see if the dim bulb stays bright.  If it does then the transformer is probably not the problem.  Be warned though… Getting that transformer out and then re-installed is a pain to do.

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Hello, im from Germany and need your Help.

These two capacitors are defective. do you know the data for these?

TH16001 and TH16002.

 

Thank You

Max

Hi guys, I own a connect amp that was plugged (by previous owner) in to 220v when switch was on 110 v.

I replaced the fuse, replaced the TVR14241 (mov) and i noticed that the TH16001 also cracked. I could not source the Sck054 needed to replace this part in my local electronics store, so I hardwired it for now, and everything works perfectly. 

Questions are:

- with normal use (no power surge, no wrong voltage), will the unit get damaged if I keep it like that? 

- is th16001 used in 220v setup, or is it for 110v only, and th16002 for 220v?

 

If it will Increase the lifespan of the unit, i will order the SCk054 online.

 

Thanks for this super interesting group discussion, got me already quite far!

The thermistors here are NTC (negative temperature co-efficient).  These will have a higher resistance when cold than once they warm up.  I’m not an expert but I think that the purpose is to limit the inrush current when the device is first plugged in.  These are used in most sonos devices that drive speakers.  Each of these has large capacitors that charge up, and which will draw large amounts of current quickly without the thermistors.  You may notice your lights dim a bit when you plug in a device without them.  I notice this dimming with the ZP120 Connect:AMP devices, and that’s with the thermistors working!

The thermistors are active in both 110v and 220v devices.

Update: removed almost all diodes from underside op primary side. Theyre all Good. Something I noticed is that all the 5 points of this winding in the secondary side are shorted together, is this right? 

 

I have noticed that the 4 diodes (marked with black stripe) do not give any Reading on my multimeter.

 

thanks! I found a short on the mosfet side, but to be sure, I also want to replace the schottky diodes on the other side… Do you have any idea on what replacement part to order for these? 

If you are referring to the pair of TO220 Schottkys mounted to the case, those are 10 Amp 100 Volt.  Part number SBR1010CT

 

the short I mentioned was not correctly diagnosed. So No short is detected on the mosfet side. Schottky diodes also seemed ok after removing them.
 

I build a dim light bulb tester, replaced the 10 ohm resistor, and removed the MOSFET’s and schottky diodes. When plugging the device in, the bulb goes full brightness. I am using a 53W bulb. Also plugged it in With the input/network card removed. Lamp still goes on… Owner told me the damage was probably caused by water as the amp was placed under a bathtub… Any thoughs? Not sure If the PWM is still ok But as I replaced it last month, it should be.

Hello, im from Germany and need your Help.

These two capacitors are defective. do you know the data for these?

TH16001 and TH16002.

 

Thank You

Max

Hi guys, I own a connect amp that was plugged (by previous owner) in to 220v when switch was on 110 v.

I replaced the fuse, replaced the TVR14241 (mov) and i noticed that the TH16001 also cracked. I could not source the Sck054 needed to replace this part in my local electronics store, so I hardwired it for now, and everything works perfectly. 

Questions are:

- with normal use (no power surge, no wrong voltage), will the unit get damaged if I keep it like that? 

- is th16001 used in 220v setup, or is it for 110v only, and th16002 for 220v?

 

If it will Increase the lifespan of the unit, i will order the SCk054 online.

 

Thanks for this super interesting group discussion, got me already quite far!

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thanks! I found a short on the mosfet side, but to be sure, I also want to replace the schottky diodes on the other side… Do you have any idea on what replacement part to order for these? 

If you are referring to the pair of TO220 Schottkys mounted to the case, those are 10 Amp 100 Volt.  Part number SBR1010CT

 

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I'm sorry, but I'm going to be stupid trying to find a suitable spare part.Can someone give me a link to a suitable spare part, e.g. at mouser or digikey?Many Thanks

Either of these will work (both are in stock as of now)

Mouser #: 527-RL4504-3.2859S54

Mouser # 954-5D2-10LD

readings at the pins. I thought I could not test this because when I power on the device it blows up. I 

I have an educated guess about what is wrong with your device.  If you replaced the PWM and it still doesn’t work, then I’d check the two mosfet devices identified in these images.  Look for a short between the various pairs of pins (you should not find any 0V drops if you test the 6 combinations with a diode tester).  If you don’t have a diode tester, you can just remove the 2 components and see if the device boots up. 

These devices are part of the circuit that is used to generate 36V power that is used to drive the amplifier.  It is only active when the device is actually playing music.  An otherwise working device will boot up without them, and will even play at very low volume.  After booting up without the 36V present, you won’t be able to turn up the volume, and the device will start flashing amber.  This isn’t permanent and it will go away once you replace the mosfets.

When the time comes, be aware that the silver clip on the top can be a pain to replace.  It can be bent open with two sets of pliers so that it is just a bit narrower than the diodes it covers.  That will let it do its job and it will be much easier to replace.

 

thanks! I found a short on the mosfet side, but to be sure, I also want to replace the schottky diodes on the other side… Do you have any idea on what replacement part to order for these? 

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I'm sorry, but I'm going to be stupid trying to find a suitable spare part.Can someone give me a link to a suitable spare part, e.g. at mouser or digikey?Many Thanks
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But sure… if you can find an SCK-053 (another manufacturer perhaps), then that would work.  I think you want the first two digits >=5 and the last digit 3 or higher.

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Do you mean a SCK-054 or a SCK-053 with 4A? Anwalt,here in germany, I don't find anyone,  who sells one of them. 

I meant SCK-083.  Here is a datasheet for the series… https://datasheetspdf.com/pdf-file/924750/Microtherm/SCK-054/1.  Looks like an SCK-103 will work too.

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Do you mean a SCK-054 or a SCK-053 with 4A? Anwalt,here in germany, I don't find anyone,  who sells one of them. 

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TH16001 and TH16002.

Hi there, are these thermistors the same as they are in an playbar? In my playbar, the green thermistor are burned and I´m looking for the type.

SCK-054 or SCK-083 will work.  These limit inrush current, and either of these does that (they have 5 and 8 ohms of initial resistance).  The maximum amperage is 4A for the SCK-053, and 3A for SCK-083.  Either of these is more than enough current for a playpar.

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Hello, im from Germany and need your Help.

These two capacitors are defective. do you know the data for these?

TH16001 and TH16002.

 

Thank You

Max

Hi there, are these thermistors the same as they are in an playbar? In my playbar, the green thermistor are burned and I´m looking for the type.

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I forgot to attach images to my previous message.  Here they are… the mosfets are marked in red boxes.

ZP120 underside - MOSFETs marked with red box
ZP120 internal - MOSFETS marked with red box

 

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readings at the pins. I thought I could not test this because when I power on the device it blows up. I 

I have an educated guess about what is wrong with your device.  If you replaced the PWM and it still doesn’t work, then I’d check the two mosfet devices identified in these images.  Look for a short between the various pairs of pins (you should not find any 0V drops if you test the 6 combinations with a diode tester).  If you don’t have a diode tester, you can just remove the 2 components and see if the device boots up. 

These devices are part of the circuit that is used to generate 36V power that is used to drive the amplifier.  It is only active when the device is actually playing music.  An otherwise working device will boot up without them, and will even play at very low volume.  After booting up without the 36V present, you won’t be able to turn up the volume, and the device will start flashing amber.  This isn’t permanent and it will go away once you replace the mosfets.

When the time comes, be aware that the silver clip on the top can be a pain to replace.  It can be bent open with two sets of pliers so that it is just a bit narrower than the diodes it covers.  That will let it do its job and it will be much easier to replace.

 

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Ok thanks for your fast reply, I indeed looked at the posts before and saw the scheme of all the readings at the pins. I thought I could not test this because when I power on the device it blows up. I will build a dim light tester, check the transformer and the pwm again as well as the diodes. I have a very cheap multimeter with a diode function, is this trustworthy?

Yes even a cheap diode tester should work.

 

Ok thanks for your fast reply, I indeed looked at the posts before and saw the scheme of all the readings at the pins. I thought I could not test this because when I power on the device it blows up. I will build a dim light tester, check the transformer and the pwm again as well as the diodes. I have a very cheap multimeter with a diode function, is this trustworthy?

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I hope someone in this thread can help me as it’s been a while since this thread was created. I have a ZP120 from a friend of mine. I opened it up and immediately saw the blue 10 ohm 2W resistor was blown near the pwm (I think it’s called) with the black heatsink attached to it. I replaced both of these components as I thought the resistor had blown due to the pwm being bad. After replacing these components, the resistor blew again after 30 seconds or so. Anyone has an idea on where the short could be? I also removed the clips of the transistors and the diodes to their heatsinks and those show a small sign of black burn marks.

I’ve fixed a lot of the zp120, but this is one that I don’t know of a definitive fix for, and I haven’t been 100% successful trying to fix it.  90% of the time, when there is a blown 10ohm resistor, just replacing it gets the device working again.  Similarly, replacing a bad PWM usually does the trick.

You should look at info earlier in this thread (or just google it) for how to build a dim bulb tester.  This has a huge advantage in this kind of case.  On a broken device, the bulb will glow brightly, but it won’t dim back as it should (once the power supply capacitors are charged).  It serves to limit current, and will prevent more components from failing every time you test something.  Without this, you may end up replacing the 10 ohm and pwm multiple times.

You can check the PWM device by testing each pair of pins using a diode tester (test in both directions).  You should get either infinite or ~ 0.6V between pins.  If you get a 0V reading between two pins, your PWM is bad again.

If you remove the PWM, try powering up the device without it.  If it doesn’t draw a ton of current (ie: the dim bulb goes out), then that confirms that the problem is ‘downstream’ of the PWM.

Check the transformer.  There are 5 pins on each of the primary and secondary sides.  They are organized as one group of 3 with a centre tap, and a separate (isolated) group of 2.  That makes 4 separate windings on the same core.  You should get low resistance across each coil within each winding, but no continuity between any two different coils.  If you find continuity between two different coils, then you have a short (hope that makes sense).  Also, with a good multimeter, you should find 0.1 or 0.2 ohms when measuring a coil.  If you get 0 ohms, then you may have a short within a coil.

Here is a less likely bit that you can check which is easy to check… There are 4 largeish surface mount diodes near one of the corners of the board on the underside (across from the power input).  Check these 4 to see if any have failed using a diode tester.  (You can do it in circuit)  I don’t think it would cause your issue, but these do go fairly often in my experience.

 

I hope someone in this thread can help me as it’s been a while since this thread was created. I have a ZP120 from a friend of mine. I opened it up and immediately saw the blue 10 ohm 2W resistor was blown near the pwm (I think it’s called) with the black heatsink attached to it. I replaced both of these components as I thought the resistor had blown due to the pwm being bad. After replacing these components, the resistor blew again after 30 seconds or so. Anyone has an idea on where the short could be? I also removed the clips of the transistors and the diodes to their heatsinks and those show a small sign of black burn marks.


I have no idea what kind of solder that Sonos uses, but it is insane. In order to get it to melt, I had to get my Hakko iron up to 900 degrees. 700 (its default) would barely get it to melt. Getting it off components was a chore. That PWM and heat sink took a good 45 minutes to get off along with about 2 feet of desoldering braid. I am surprised I didn't destroy contacts as I really had to put that iron on for a while to get that solder to move. I tried a desoldering pen too, but to no avail. The best way to get it off was keep cracking at it with desoldering braid. I would love to hear if anyone has any hacks or ways to deal with such a problem.  ...
 🙂

  • The solder was no doubt lead-free, which has a much higher melting temperature than lead-content solder.   The solder that is touched directly by the iron will melt but due to temperature drop further away from the iron, some solid solder will remain. Use a solder sucker to get as much solder off the joint as possible.  There will probably be some solder remaining in hidden areas which makes it impossible to pull the component out.  The heat from the solder iron does not get conducted to those hidden remnants of lead-free solder; so add some leaded solder* to the joint and let it flow in.  The leaded solder will mix with the lead free solder and alter the alloy to lower the melting temperature.   The added solder provides a better heat conduction path.  Suck it clean again.  Repeat a few times if needed.
    Apply the iron to the component lead, not to the pcb pad.  The copper clad of the pc board will peel away from the fiberglass if it get heated too much.

    *Rosin core solder can get messy, and the rosin flux is not really needed since the copper has already been tinned.  Find a spool of lead solder without a flux filled center in the plumbing department.

Hello, I replaced the components and it works again. Thanks very much

 

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Hi Tim, thank you. I have now ordered two of them. Can I destroy them by changing the AC voltage from 230V to 115V on the 230V grid?

Yes that could cause a lot of damage.  The usual rectification generates the input times the square root of 2 as DC voltage.  SO 115V input translates to about 162V.  The switch on the back adds a voltage doubler to the rectifier circuitry.  With a 115V input, that produces 320V internally, which drives the high voltage circuitry.  If 115V is selected but the input is 230V, then it would internally generate 640V DC.  That could break a lot of things.  All of the power passes through the thermistors, and they blew up in protest of the voltage.  The question is if they went before anything else ‘downstream’ died or not.  It is possible that there was also damage to the PWM chip.  This is the four pin device on a heatsink next to the transformer.  You can check if it’s pins are shorted or not.  If there are short circuits between pins then it is dead.  If there are no shorts, it doesn’t mean that it isn’t broken though.

Hi Tim, thank you. I have now ordered two of them. Can I destroy them by changing the AC voltage from 230V to 115V on the 230V grid?

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