IcePower module

[Phil Allison]

Hi to all my fans,

just completed repairs on one of these:

http://www.sound-power.ru/files/doc/ICEpower125ASX2_datasheet.pdf

Found it fitted inside a mini-size bass instrument amplifier, which the owner had just purchased over the net and failed on him at first power up.

Smelling a rat, I checked the AC switch on the rear panel first - blow me down, it was set to 120VAC and we live in a 240V country.

Reset the switch, then it drew zero AC current - no surprise.

Replaced the blown 5AT fuse in the IcePower module and then the PSU began hiccupping - drawing an amp or two very briefly then shutting off every few seconds.

IME feeding double AC supply voltage to a unit with a SMPS is almost always fatal, sure the AC fuse blows but semis in the HV part of the circuit fail in a fraction of a second. But these must be OK this time because the PSU was hiccupping - ie working but sensing an overload so shutting down.

Soon enough, multimeter testing showed two small power mosfets on the output side of the SMPS tranny were shorted while two others seemed OK. But what the heck are mosfets doing there ?

Well, it's the fist time I have come across seen a *synchronous rectifier* in such an unit. IcePower had certainly gone all out to reduce losses and heat in this module by using a synchronous bridge.

The particular TO-252 fets here are made by ON, number FDD86110 rated at 100V and 8mohms on resistance.

Removing the duds cleared all shorts and after fitting some new ones ( delivered to me by Element14, from their Singapore warehouse ) I gingerly Variaced the unit up from zero.

No hiccupping this time and it began to run normally - after which it passed all my usual bench testing, no problems.

FYI:

AC current draw was 120mA at idle, 2.4A at full power (340W rms/4ohms)

No PFC and inrush surges were about 25A for a few milliseconds.

There was a residual sine wave signal on the audio output of about 1V at 500kHz - no biggie except it makes THD testing a right PITA.

I find it odd the way the SMPS failed, just two mosfets in the secondary rectifier, nothing else. For a brief time, the DC supply to the switching fets must have been nearly double voltage.

Seems the two rectifier fets failed SHORT instantly and protected the rest of the circuitry - remember the power supply is NOT regulated, just a square wave inverter running at 100kHz.

I also feel that supplying an expensive amplifier to a buyer living in a 240V country with the AC inlet set to 120V and giving NO warning is criminal. BTW the amp was fitted with a regular IEC inlet which most of the world uses for 240VAC.

Any comments?



.... Phil

 

[John-Del]

On Thursday, September 19, 2019 at 11:52:31 PM UTC-4, Mr. Charm & Warmth wrote:

Hi to all my fans,

**There's internet in hell?

just completed repairs on one of these:

http://www.sound-power.ru/files/doc/ICEpower125ASX2_datasheet.pdf


Smelling a rat, I checked the AC switch on the rear panel first - blow me down, it was set to 120VAC and we live in a 240V country.


I also feel that supplying an expensive amplifier to a buyer living in a 240V country with the AC inlet set to 120V and giving NO warning is criminal.

** I've found that when an item fails, the customer will flip every switch in a vain attempt to "repair" the failure. Even though the amp failed on first use, we don't actually know where the switch was set when the customer obtained the amp. There's an even (or better) chance the customer flipped it after the amp failed.

Any comments?

**Good repair.

 

[Rob]

Phil Allison <pallison49@gmail.com> wrote:
> Any comments?

It may seem like this PSU is fancy, but in a really modern PSU there is
no 120/240 switch and the PSU automatically works between 80 and 250V AC.

 

[Phil Allison]

John Dope wrote:

----------------

Hi to all my fans,


**There's internet in hell?

** Small mistake, the internet IS hell.

just completed repairs on one of these:

http://www.sound-power.ru/files/doc/ICEpower125ASX2_datasheet.pdf


Smelling a rat, I checked the AC switch on the rear panel first - blow me down, it was set to 120VAC and we live in a 240V country.


I also feel that supplying an expensive amplifier to a buyer living in a 240V country with the AC inlet set to 120V and giving NO warning is criminal.


** I've found that when an item fails, the customer will flip every switch in a vain attempt to "repair" the failure. Even though the amp failed on first use, we don't actually know where the switch was set when the customer obtained the amp. There's an even (or better) chance the customer flipped it after the amp failed.

** Errr - nope.

The particular "switch" is tiny - looks like a round, 20mm panel fuse holder with sub mm white print saying 120/240 - PLUS requires screw driver to operate.

Every knowable fact points at the supplier being in the USA and sending the buyer here a "cardboard box" with a local model inside.

The chance the amp arrived in the buyer's hand with a faulty low voltage mosfet in the synchronous rectifier cct AND no other fault is miniscule.

Any comments?


**Good repair.

** I was careful, observant and a tad lucky.

Replacing the 2 DPAK mosfets mounted flat on the PCB was a new job to me - everything I had read suggested it required solder paste & liquid flux that I did not have.

In the end, I used 1.2mm Savbit 60/40 wire solder, a Hakko FX-888 iron set to 330 C and acted damn quick.



...... Phil

 

[Phil Allison]

Rob wrote:
-----------

Phil Allison

Any comments?


It may seem like this PSU is fancy, but in a really modern PSU there is
no 120/240 switch and the PSU automatically works between 80 and 250V AC.

** Yep - most of those kind of SMPSs are know as "PFC corrected" .

The incoming AC is rectified and converted to 400V DC by a switching converter that tracks the incoming AC voltage. Makes the current wave follow the voltage wave ( both sine) so the "power factor" is close to unity.

Has advantages in terms of how many units can be run of the same power circuit and is often mandated in regulations for lighting and computer products.

But not for domestic or entertainment audio.


...... Phil

 

[Rob]

Phil Allison <pallison49@gmail.com> wrote:
> Every knowable fact points at the supplier being in the USA and sending the buyer here a "cardboard box" with a local model inside.

Once I had a defective PSU in a Dell desktop PC, made a case at the local
Dell phone number, got sent a PSU from a European parts center, and it
was set to 120V. BANGGG!! (OF COURSE I did not check that! All newly
delivered Dell PCs come with the switch correctly set for our region!
and there was no "please be advised that you need to check the setting"
note packed with it either...)

Called them again, got sent another PSU, again set to 120V. Of course
this time I switched it before plugging it in.

I think this is crazy. When you manufacture PSUs and have to have a
default setting, then at least SET IT TO 240V!!!
When the local line is 120V then at least it will not fail, and when
it does not work you can still change the setting.

 

On Friday, 20 September 2019 14:31:05 UTC+1, Phil Allison wrote:

Rob wrote:
-----------

Phil Allison

Any comments?


It may seem like this PSU is fancy, but in a really modern PSU there is
no 120/240 switch and the PSU automatically works between 80 and 250V AC.


** Yep - most of those kind of SMPSs are know as "PFC corrected" .

The incoming AC is rectified and converted to 400V DC by a switching converter that tracks the incoming AC voltage. Makes the current wave follow the voltage wave ( both sine) so the "power factor" is close to unity.

Has advantages in terms of how many units can be run of the same power circuit and is often mandated in regulations for lighting and computer products.

But not for domestic or entertainment audio.


..... Phil

PFC is mandated for domestic goods above 20w here.
PFC correction & the ability to run at 120 & 240 without changing a switch are of course 2 separate things.


NT

 

[Phil Allison]

Some Bullshitting Idiot called tabb...@gmail.com wrote:

--------------------------------------------------------

PFC is mandated for domestic goods above 20w here.

** No it isn't.

EN 61000-3-2 set some limits on the levels of harmonic current permitted.

http://www.epsma.org/PFC%20Guide_November%202010.pdf

These limits are sufficiently high that the majority of electronic devices intended for domestic use meet the standard with no special correction circuit or device installed.

PFC correction & the ability to run at 120 & 240 without changing
a switch are of course 2 separate things.

** But are closely related since active PFC allows a designer to fairly easily achieve 85VAC to 265VAC operation and which many items already have.

Wide input range SMPS without active PFC exist, but IME are less common.


...... Phil

 

On Saturday, 21 September 2019 02:49:16 UTC+1, Phil Allison wrote:

Some Bullshitting Idiot called tabby wrote:

--------------------------------------------------------

PFC is mandated for domestic goods above 20w here.


** No it isn't.

EN 61000-3-2 set some limits on the levels of harmonic current permitted.

http://www.epsma.org/PFC%20Guide_November%202010.pdf

These limits are sufficiently high that the majority of electronic devices intended for domestic use meet the standard with no special correction circuit or device installed.

Silly me, I thought it was obvious I was referring to devices with poor pf.


NT

 

[Phil Allison]

Some Nut Case Damn LIAR called tabb...@gmail.com wrote:

----------------------------------------------------

PFC is mandated for domestic goods above 20w here.


** No it isn't.

EN 61000-3-2 set some limits on the levels of harmonic current permitted.

http://www.epsma.org/PFC%20Guide_November%202010.pdf

These limits are sufficiently high that the majority of electronic
devices intended for domestic use meet the standard with no special
correction circuit or device installed.

----------------------------------------------------

Silly me, I thought it was obvious I was referring to devices with poor pf.

** FFS dickwad, the regs do not even mention the term "power factor".

Try actually reading them before blowing bullshit out you arse.

PFC is in no way "mandated" .



..... Phil

 

[Rob]

Phil Allison <pallison49@gmail.com> wrote:
> Wide input range SMPS without active PFC exist, but IME are less common.

Before the PFC solution there were SMPS that used the standard
rectifier/doubler setup with a TRIAC in place of the jumper that
normally selects 120V/240V operation.

 

On Saturday, 21 September 2019 10:26:12 UTC+1, Phil Allison wrote:

Some Nut Case Damn LIAR called tabby wrote:

----------------------------------------------------


PFC is mandated for domestic goods above 20w here.


** No it isn't.

EN 61000-3-2 set some limits on the levels of harmonic current permitted.

http://www.epsma.org/PFC%20Guide_November%202010.pdf

These limits are sufficiently high that the majority of electronic
devices intended for domestic use meet the standard with no special
correction circuit or device installed.

----------------------------------------------------


Silly me, I thought it was obvious I was referring to devices with poor pf.



** FFS dickwad, the regs do not even mention the term "power factor".

Try actually reading them before blowing bullshit out you arse.

PFC is in no way "mandated" .



.... Phil

Horse.

 

[Phil Allison]

Rob wrote:
-------------

Phil Allison


Wide input range SMPS without active PFC exist, but IME are less common.

Before the PFC solution there were SMPS that used the standard
rectifier/doubler setup with a TRIAC in place of the jumper that
normally selects 120V/240V operation.

** Yeah - the cct starts off in the 240V position and jumps down to the 120V setting if the output voltage is much too low.

Think makers called it "auto-select" or something like that.

Few examples were ever made so I suspect their were some issue with it like when the AC supply was dodgy - ie brown outs and such like.

It's safer to have the setting locked to the AC voltage where you live - and not have it jump to voltage doubling cos of a short term voltage drop.

The PFC solution normally works brilliantly, long as the AC supply impedance is reasonably low. If there are hundreds of metres of 15amp cable between the load and the supply - all bets are off.

Then, if the AC voltage drops, the load draws more current causing the voltage to drop more - and well you get the idea.


..... Phil

 

On Saturday, 21 September 2019 12:53:01 UTC+1, Phil Allison wrote:

Rob wrote:
Phil Allison


Wide input range SMPS without active PFC exist, but IME are less common.

Before the PFC solution there were SMPS that used the standard
rectifier/doubler setup with a TRIAC in place of the jumper that
normally selects 120V/240V operation.


** Yeah - the cct starts off in the 240V position and jumps down to the 120V setting if the output voltage is much too low.

Think makers called it "auto-select" or something like that.

Few examples were ever made so I suspect their were some issue with it like when the AC supply was dodgy - ie brown outs and such like.

It's safer to have the setting locked to the AC voltage where you live - and not have it jump to voltage doubling cos of a short term voltage drop.

The PFC solution normally works brilliantly, long as the AC supply impedance is reasonably low. If there are hundreds of metres of 15amp cable between the load and the supply - all bets are off.

Then, if the AC voltage drops, the load draws more current causing the voltage to drop more - and well you get the idea.


.... Phil

Safest is to simply design the psu to output the correct voltage with either 240 or 120 in. It's not a big problem to design an smpsu to cope with that from the get go, so there's no need for any bolt-ons to try to get round an inadequate working range. And that's exactly what most do.


NT

 

[Adam]

On 2019-09-20, tabbypurr@gmail.com <tabbypurr@gmail.com> wrote:

PFC correction & the ability to run at 120 & 240 without changing a
switch are of course 2 separate things.

The typical PFC circuit is a boost regulator placed between the rectifier
and the reservoir cap. In this way, the reservoir cap can charge during
the entire AC cycle instead of only during the peaks, improving the power
factor. But this also has the effect that the PWM circuit will see the
same input voltage regardless of the line voltage. So, wide input range
often comes along with PFC.

-- Adam

 

[Phil Allison]

Adam wrote:
-----------

The typical PFC circuit is a boost regulator placed between the rectifier
and the reservoir cap. In this way, the reservoir cap can charge during
the entire AC cycle instead of only during the peaks, improving the power
factor.

-------------------------------------------------------------

** Most PFC circuits have damn near sine wave current draw, so the PF is around 0.9 to 0.95. However, with the vast majority of domestic, electronic appliances this is of no advantage to the user or the supply system.

Only lighting and computers are required to have good PFs in places like Europe and the US while the main reason for that is cos it allows twice as many of these to run from the same AC supply, compared to non PFC versions.

Many buildings have hundreds of light fittings installed and large numbers of mains powered PCs for workers - and that is where it matters!

FYI: domestic fridges, microwave ovens plus most washers and clothes driers have long had near sine wave current draw and so good power factors.

But this also has the effect that the PWM circuit will see the
same input voltage regardless of the line voltage. So, wide input range
often comes along with PFC.

** Correct.


...... Phil

 

[Jeff Urban]

>** Yeah - the cct starts off in the 240V position and jumps >down to the 120V setting if the output voltage is much too low.

That's what I thought but being in a 120 volt country never had to deal with it.

>It's safer to have the setting locked to the AC voltage where >you live - and not have it jump to voltage doubling cos of a >short term voltage drop.

That makes perfect sense in a 240 country.

Here, it can't really hurt itself.

There are some high power amps here that need 240. They just can't run on 120. Those don't switch down.

Anyway yes, you are definitely better off with a switch.

 

[Trevor Wilson]

On 20/09/2019 1:52 pm, Phil Allison wrote:

Hi to all my fans,

just completed repairs on one of these:

http://www.sound-power.ru/files/doc/ICEpower125ASX2_datasheet.pdf

Found it fitted inside a mini-size bass instrument amplifier, which the owner had just purchased over the net and failed on him at first power up.

Smelling a rat, I checked the AC switch on the rear panel first - blow me down, it was set to 120VAC and we live in a 240V country.

Reset the switch, then it drew zero AC current - no surprise.

Replaced the blown 5AT fuse in the IcePower module and then the PSU began hiccupping - drawing an amp or two very briefly then shutting off every few seconds.

IME feeding double AC supply voltage to a unit with a SMPS is almost always fatal, sure the AC fuse blows but semis in the HV part of the circuit fail in a fraction of a second. But these must be OK this time because the PSU was hiccupping - ie working but sensing an overload so shutting down.

Soon enough, multimeter testing showed two small power mosfets on the output side of the SMPS tranny were shorted while two others seemed OK. But what the heck are mosfets doing there ?

Well, it's the fist time I have come across seen a *synchronous rectifier* in such an unit. IcePower had certainly gone all out to reduce losses and heat in this module by using a synchronous bridge.

The particular TO-252 fets here are made by ON, number FDD86110 rated at 100V and 8mohms on resistance.

Removing the duds cleared all shorts and after fitting some new ones ( delivered to me by Element14, from their Singapore warehouse ) I gingerly Variaced the unit up from zero.

No hiccupping this time and it began to run normally - after which it passed all my usual bench testing, no problems.

FYI:

AC current draw was 120mA at idle, 2.4A at full power (340W rms/4ohms)

No PFC and inrush surges were about 25A for a few milliseconds.

There was a residual sine wave signal on the audio output of about 1V at 500kHz - no biggie except it makes THD testing a right PITA.

I find it odd the way the SMPS failed, just two mosfets in the secondary rectifier, nothing else. For a brief time, the DC supply to the switching fets must have been nearly double voltage.

Seems the two rectifier fets failed SHORT instantly and protected the rest of the circuitry - remember the power supply is NOT regulated, just a square wave inverter running at 100kHz.

I also feel that supplying an expensive amplifier to a buyer living in a 240V country with the AC inlet set to 120V and giving NO warning is criminal. BTW the amp was fitted with a regular IEC inlet which most of the world uses for 240VAC.

Any comments?

**IcePower is cheap shit. A Rotel receiver recently landed on my bench
with a seriously damaged IcePower module. I requested a service manual
from the importer (International Dynamics). The manual arrived and it
was very comprehensive, EXCEPT that the IcePower modules (an output
stage and power supply) were listed as blocks, with no schematics
available. Since the damage was fairly extensive (some burned resistors
and other dead bits and bobs), I just ordered a new module. Since it had
to come from B&O, my client had to wait.

FWIW: I've also had an earlier IcePower based amplifier in for service.
When I posed questions to the manufacturer about the excessive levels of
high frequency crap emanating from the amplifier, I was politely (well,
not so politely) told that I should not be testing the amplifier!

IcePower is cheap shit. Cleverly designed, but cheap.


--
Trevor Wilson
www.rageaudio.com.au

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

 

[Phil Allison]

Trevor Wilson wrote:

-----------------------

I also feel that supplying an expensive amplifier to a buyer living in a 240V country with the AC inlet set to 120V and giving NO warning is criminal. BTW the amp was fitted with a regular IEC inlet which most of the world uses for 240VAC.

Any comments?


**IcePower is cheap shit.

** TW seems to have missed the fact that the above is about some unknown agent selling bass amps to amateur musicians as "cardboard boxes" over the net.

A Rotel receiver recently landed on my bench
with a seriously damaged IcePower module. I requested a service manual
from the importer (International Dynamics). The manual arrived and it
was very comprehensive, EXCEPT that the IcePower modules (an output
stage and power supply) were listed as blocks, with no schematics
available.

** The modules are a mass of SMD - so essentially non repairable by audio techs with regular bench equipment only.

FWIW: I've also had an earlier IcePower based amplifier in for service.
When I posed questions to the manufacturer about the excessive levels of
high frequency crap emanating from the amplifier, I was politely (well,
not so politely) told that I should not be testing the amplifier!

** The one in question showed 2V rms at 500kHz across the bridge mode outputs.

Completely harmless, far as I can tell.

IcePower is cheap shit. Cleverly designed, but cheap.

** As usual, TW prefers his emotional opinions to fact so simply has no point to make.

I have no issue with IcePower, the module suffered minimal damage from what has to be the worst imaginable accident.


..... Phil

 

[Jeff Urban]

** The one in question showed 2V rms at 500kHz across the bridge >mode outputs.

Completely harmless, far as I can te

Not if you got piezo tweeter, and some electrostatics.