EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: Hextejas on January 30, 2021, 02:38:47 pm
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The razor is a BabyLiss Pro FX788 and it is a hair salon quality for cutting hair.
Plug it in, turn it on and nothing happens. So, I took it apart and the wall wart shows from about 11.12 to about 14.5 V DC and fluctuates like crazy. Sounds like a replacement for the power supply should do the trick. Problem is that there is nothing on the power supply to indicate the voltage.
The label on the razor does show this.
Input 100-240V AC, 50-60hz, .68A, Max 11W.
So, I connected it to a desktop power supply of 5V and it started running. I also upped the voltage to 12V and it ran a lot faster. No surprise.
So, I was looking to size a power supply for it but any of the ones that I see in my electronics store have a pretty small diameter wire.
If it were to draw say 11W, .68A, that would be around 22V, yes ?
Take a look at the picture that shows arrows A and B. Arrow A is the original cord and Arrow B is the 12V wall wart from the electronics store.
Quite a bit smaller.
So what would you say to a 12V wall wart though I don't know how to get around the skinny wire.
Any suggestions ?
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If it is your razor, then you should remember the tone it makes at normal speed. Adjust voltage until you hear a similar tone. Skinny wire will hold if you do not use it a lot. You can always fix it if it breaks. Or try to attach the original wire to the new wall wart. That is what I can say.
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Thank you Manul. I was not so much worried about the wire breaking as I was about it being able to handle 11W without burning up. And unfortunately I don't know what the original sound was. Great idea though. I might be able to get a similar one and see what it sounds like,
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Power = Volts x Amps
Volts = 11W / 0.68A = 16V
It would help if you could tell us the markings on the ICs on the PCB in the razor.
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https://www.vipbarbersupply.com/products/babylisspro-goldfx-rosegoldfx-clipper-870g-870rg-charger (https://www.vipbarbersupply.com/products/babylisspro-goldfx-rosegoldfx-clipper-870g-870rg-charger)
"Output 4.5V DX 1200mA"
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The OP's photo appears to show an FX880, not FX788. ???
FWIW, the FX880E is rated at 12VDC, 1000mA:
https://www.babylisspro.eu/Docs/50faae3d-d794-4821-b61f-d4908c6c7614/16_FX880E_IB_nouvelle%20version_.pdf (https://www.babylisspro.eu/Docs/50faae3d-d794-4821-b61f-d4908c6c7614/16_FX880E_IB_nouvelle%20version_.pdf)
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You're correct. I got the model number wrong it is an FX880.
And that seems to mean that I will need a 12V supply rather than 5V. It runs using the 5V but I guess it might be a bit too slow or lack power if I continue with the 5V. It sure buzzes a lot louder running at 12V.
I will try and get a good picture of the internals.
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Ok, I got pictures of the insides.
The chips are:
UTC494
DTM4420 x3
And the board does say
Rohs
E357886
94V-0
==============
13-Jul-2012
FX880-A1
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Open up the original power supply and repair it, at least 90% of the time the problem is just one or more electrolytic capacitors that have failed. If you have to break it to get it open then at least you can get it working and measure the characteristics.
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http://d1.amobbs.com/bbs_upload782111/files_48/ourdev_702817MY8ZTV.pdf (http://d1.amobbs.com/bbs_upload782111/files_48/ourdev_702817MY8ZTV.pdf)
DM4420 is an N-ch MOSFET
SOP-8
Vds = 30V
Vgs = +/-20V
Vt = 1.5V
Vg_10V = 8.5V
Vg_4.5V = 9.6V
Id = 13A
UTC494 is a PWM controller. It has a minimum supply voltage of 7V and a maximum of 40V.
http://www.unisonic.com.tw/datasheet/TL494.pdf (http://www.unisonic.com.tw/datasheet/TL494.pdf)
I'm guessing the capacitor has a voltage rating of 25V rather than 16V or less.
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I have same hair clipper, I need R22 value. Thanks[attachimg=1]
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~ 17V i.e. 11/0.68
so use half to 3/4 of it i.e. ~ 9 - 13V for simple rule in good DC M optimum (not max) usage
obtain any AC-DC circuit fullfill it with ~ 3/4 A