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Introdução

The IC (chip) inside the lamp seems to die slowly resulting in flickering/flashing lamp operation when using the radio. Also, the buttons may become unresponsive.

The problem occurs specifically when the device is cold and/or humid. Heating up the IC makes it work again.

Peças

Nenhum componente especificado.

  1. Philips Wake-Up HF3520 Power supply repair, Start: passo 1, imagem 1 %32 Philips Wake-Up HF3520 Power supply repair, Start: passo 1, imagem 2 %32
    • There is a screw under the shiny UL sticker. Remove sticker and screw to remove this bottom panel. There are two tabs holding the panel into clock/light, so you might have to wiggle panel forward and out to remove it.

    • Next we need to gain access to more screws.

    There is one screw under this tab that's hold the front ring attached in fact. I guess you should have removed it too before prying this ring open

    Luuk Akkerman - Responder

    That one does not hold the ring but the cover (step 4).

    Wozu das denn -

  2. Philips Wake-Up HF3520 Power supply repair, Prying open: passo 2, imagem 1 %32 Philips Wake-Up HF3520 Power supply repair, Prying open: passo 2, imagem 2 %32
    • Flipping the light upside down will present a small section of the bezel that can be pried upward. It is a small plastic strip with hooks that have to be disengaged to be removed. (tricky)

    Getting this section off/out without damaging it is nearly impossible. It’s hooked under the rear rim and it is held down by three clips. I ended up cutting the little bows that connect it to the back and then used pliers on one side to, well, basically break it out…

    Adjel van der Meer - Responder

    This stage was tricky but by poking a small flat-head screwdriver in alongside the tabs shown in the photo and twisting, I was able to remove it in one piece. Careful studying of of the image above shows where you need to go. Thanks for this excellent guide, I would never have figured this out without it.

    Nick Page - Responder

    Use a plastic tool or a something like a credit card to get that part out: it won’t break it and it is actually quite easy to remove (same tool used for smartphone)

    laurent reichsrath - Responder

    Wow, this would have been impossible to do without seeing the pic of the part! I managed to get it free using a tiny flat-head screwdriver to the clip (all three, one by one) and a larger one pushing up on the rim simultaneously.

    Tamar Opher - Responder

    Thanks also from my side, it would have been an impossible mission without your guide and excellent illustrations. I also succeeded to remove the plastic strip lock with a tiny flat-head screwdriver and a pair of good steel pliers. No damage.

    Cesare Liguori - Responder

  3. Philips Wake-Up HF3520 Power supply repair, Button ring: passo 3, imagem 1 %32 Philips Wake-Up HF3520 Power supply repair, Button ring: passo 3, imagem 2 %32 Philips Wake-Up HF3520 Power supply repair, Button ring: passo 3, imagem 3 %32
    • We can finally unscrew two more Philips head screws to remove the button ring.

    Lift one end of the ring, tilting it toward the back of the alarm clock. That will get the bows out from under the rear rim so you can start removing it..

    Adjel van der Meer - Responder

  4. Philips Wake-Up HF3520 Power supply repair, Front screen shield: passo 4, imagem 1 %32
    • Now the screws holding the front screen shield need to be removed and the shield can be pulled away to the front.

    • Screw organization note for later: these screws have pointed ends

    • CAREFUL NOT TO DAMAGE THE INTERNAL SCREEN

    • Unscrew the four screws holding the inner screen assembly in place.

  5. Philips Wake-Up HF3520 Power supply repair, Inner screen assembly: passo 5, imagem 1 %32 Philips Wake-Up HF3520 Power supply repair, Inner screen assembly: passo 5, imagem 2 %32
    • The inner screen assembly can be pulled out slightly to reveal tabs on each side that hold the assembly in.

    • Pry the back tabs inwards to release.

    Need to push quite hard on the tabs, don’t be surprised

    totosolat - Responder

    Thank you for your comment. I was about to give up, then I read your comment and tried again pushing a little harder and it worked just fine!

    Ifelix -

  6. Philips Wake-Up HF3520 Power supply repair, The guts: passo 6, imagem 1 %32 Philips Wake-Up HF3520 Power supply repair, The guts: passo 6, imagem 2 %32 Philips Wake-Up HF3520 Power supply repair, The guts: passo 6, imagem 3 %32
    • The screen is connected to the plastic domed back with holes. There are two screws at the back of the base of this domed panel. Remove screws to remove screen.

    • Set screen panel aside for safe keeping.

    • More to see and modify...

    Here to note that you better remove the speaker connector and release the aerial wire removing the screw that fix it on the back. I had to replace the controller of the step-down 5 V supply, so i needed full access to the bottom board. Just to note that while reassembling I swapped by mistake the speaker and the buzzer connectors, they are the same... So be careful or you have to go through the tedious opening operation once again....

    Cesare Liguori - Responder

  7. Philips Wake-Up HF3520 Power supply repair, Replace IC: passo 7, imagem 1 %32
    • On the main PCB with the power jack, replace the MXT2410 switchmode regulator IC (SO-8 Package).

    • There is a pin-compatible device from Quorvo (ACT4060ASH-T) which has a different internal voltage reference but otherwise works fine. Only a resistor must be changed for this to work.

    • Warning: I just encountered a problem with the ACT4060. It blew up on one lamp and damaged the LEDs as well. So it seems not a perfect replacement after all.

    • The feedback Voltage for MXT2410 is 1.222V, for ACT4060 is 1.293V, so voltage divider on Pin5 must be changed accordingly.

    • One can best adjust R4+R3 (series). Remove R4, measure R3 and R4, and increase. It should measure about 10.67kOhm (R3 plus R4), and it can be slightly increased to 11.51kOhm. So basically add 1kOhm to R3+R4.

Conclusão

Arbeite die Schritte in umgekehrter Reihenfolge ab, um dein Gerät wieder zusammenzubauen.

14 outras pessoas concluíram este guia.

Thomas Widmaier

Membro desde: 05/03/2013

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22 Comments

Hi Thomas,

I have the same problem, but i do not understand what you are doing with the R3 and R4. If i remove R4, with what should i replace it?

Or how should i measure it?

Thanks in advance,

Arnoud

Arnoud Otten - Responder

Can somebody do this for mine?

June Goto - Responder

Can some one do this for me??

June Goto - Responder

I can only do it in Germany

Thomas Widmaier -

Hallo Thomas,

ich finde das ist eine tolle Anleitung zur Reparatur des Lichtweckers. Ich hatte mich auch auf den Austausch des MXT2410 konzentriet. Es kam dann aber doch anders. Nach ca. 2-3 Wochen warten auf den ACT4060 war dieser schnell eingebaut. Das Ergebnis war enttäuschend. Keine Änderung, die 5V waren nicht messbar. Bei der weiteren Fehlersuche stellte ich fest, dass der ACT4060 und die zugehörige Drossel schnell warm wurden. Jetzt ging es an die Suche nach einem Kurzschlußkandidaten. Er war dann schnell gefunden: D3 (SK24). Eine andere Schottkydiode eingebaut (diesmal aus der Bastelkiste) und es wurde wieder Licht und Musik.

Freundliche Grüße,

Roland

rpg - Responder

Thanks for the feedback. I wasn´t 100% sure the ACT4060 can work correctly. Your feedback has confirmed it will work.

Did you make a modification to the resistors ? Did you measure the voltage ?

Thomas Widmaier -

I was able to use this guide to bring a Philips Wake-Up HF3520 back from the dead. Was able to source a MXT2410SX IC via ebay (5 for $10.23), so just swapped the IC and did not touch the resistors. Thank you OP for identifying the failing component.

John Morris - Responder

I haven’t attempted the repair yet, but the tip about humidity/cold was genius!! My lamp magically works again every time I shut the windows and put the heat on… I never would have figured this out without this clue. For me this isolates the problem to the chip. Thank you!!

marziplan - Responder

Hallo Thomas,

mein HF3520 spinnt auch, wenn es kalt ist. Ich habe selber keine Ahnung von Elektrotechnik. Hättest du Interesse und Zeit ihn zu reperarieren. Ich wohne in München Oberföhring.

Viele Grüße

Mathias

mathiaskloss - Responder

Hier gibts keine Privatnachricht, leider. Bitte eMail an ifixit@e-mail.de

Thomas Widmaier -

Sicher kann ich es probieren, allerdings hab ich nur den Alternativchip hier noch irgendwo, der MXT müßte erst bestellt werden.

Alles ohne Garantie ;-)

Kannst es schicken oder vorbeibringen. Westendstraße nähe OBI. Genaueres müßte ich eine PM schreiben.

Thomas Widmaier -

Hallo Thomas,

ja die Widerstände mussten etwas angepasst werden. Auf der Platine ist Platz für einen kleinen SMD-Trimmer.

Das machte die Sache etwas einfacher. Mit Hilfe des Datenblattes und Kontrollmesungen der Spannung war die Einstellung kein Problem.

Nochmals Danke für deine tolle Anleitung,

Viele Grüße Roland

rpg - Responder

Worked for the second time with the ACT4060 and adapted resistors. However, this IC is actually specified only up to 20V, I saw afterwards. That could explain your blow-up, Thomas.

Once the external 24V power supply was also broken. I replaced it with a 12V power supply I had left over from an external hard drive.Seems to work fine and also protects the ACT4060 :-)

baatzi - Responder

Worked for the second time with the ACT4060 and adapted resistors. However, this IC is actually specified only up to 20V, I saw afterwards. That could explain your blow-up, Thomas.

Once the external 24V power supply was also broken. I replaced it with a 12V power supply I had left over from an external hard drive.Seems to work fine and also protects the ACT4060 :-)

Samson Ogboji - Responder

Hi!

Last week our HF3520 exploded in the middle of the night. I opened it and I found in another internal part (not the one you arranged) the follow stain: Damage

I don't know if my problem is the same as yours.

@goaty do you remember if inside of your lamp had the same stain?

Thank you!

Óscar Lestón - Responder

The strain in the middle besides the coil and the capacitor is just glue to keep the cable in place.

Look for other damage like blown up capacitor.

Thomas Widmaier -

Thank you so much Thomas @goaty for this detailed Fixit !

Eventhough i have experience in electronics i would never thought about the power IC for this behaviour.

II've replaced the IC with the MXT2410SX that you can find on ebay here : "https://www.ebay.com/itm/393179218389" the lamp and all it's fonctionnalities is perfect since then ! I did that like 6 months ago and it still working perfectly (sorry i've just had time to give my feedback).

Changing the IC is a little bit technic but it still conceivable with some tutos for non experienced persons.

I'm glad to discovre this community thanks to your fixit i'll try to add some of mines as possible.

Hassan Barutchi - Responder

Vielen Dank für die gute Anleitung!

Wenn bei dem Wecker irgendwelche Tasten nur noch unzuverlässig reagieren, kann man die Gelegenheit nutzen, um die zu reinigen:

- mit einer spitzen Pinzette die das weiße Klebeband vorsichtig abziehen

- Klebeband mit der Pinzette festhalten und mit einer zweiten Pinzette das im Inneren vermutlich dunkel angelaufene Metallplättchen abziehen

- Metallplättchen vorsichtig wieder glänzend polieren (bei mir hat einer der spitzen blauen Poliergummischleifer von Proxxon perfekt dafür funktioniert)

- Plättchen und Kontakt mit Isopropanol reinigen

- Plättchen wieder in seine Aussparung kleben und Klebeband mit Plättchen zurück auf die Leiterplatte kleben, vorsichtig ringsum wieder gut andrücken.

Wozu das denn - Responder

My HF3520 is down.

May I ask a question? I don't know much about converter, but why do you use an ACT 4060 ? The ACT4072 is 1.222V (but do we care?) and support 30V input.

Does it work better?

(by the way, anybody has the mxt2410 fact sheet?, and what does all this numbers mean?)

rat.aspert - Responder

I thought I was smart by using ACT4060 as replacement of MXT, but it did not work, and blew up on me, so I wrote that it is not good replacement !

Better buy MXT2410 original from China, 10pcs for around 10Dollars, it works perfect.

Thomas Widmaier -

Thanks! It was the problem in my case as well. I did't want to use new MXT2410 because I suspect that it would die after few years again. Thus, instead of ordering new MXT2410 I just desoldered it, as well as removed the Shottky diode and the inductor, and installed a bypass from a readily available module based on MP1584 (just because I already had one at hand), for example: https://www.tinytronics.nl/shop/en/power...

Alexey - Responder

Just changed the IC MXT2410 on my HF3510 and it works well now !

Thanks a lot

The symptoms was that the buttons do not work too but also the clock make noise in the middle of the night

Julien F - Responder

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