Recently the foil on my Remington F4790 got a hole in it, it makes the foil and cutter part of the razor unusable. While I placed replacement foils on order, I figured I’d just use the trimmer, but then trimmer stopped working.
Apologies for the poor image quality, they’re screengrabs from a video.
The foil and the cutters pop straight off with a little bit of a pull. Thereafter there are two small screws at the hinge point which can be loosened.
![GP012706.MP4_snapshot_00.01_[2015.10.13_19.56.49]](http://blog.gcawood.com/wp-content/uploads/2015/10/GP012706.MP4_snapshot_00.01_2015.10.13_19.56.49.jpg)
The foil and cutter head then comes out. Take care when reassembling to align the pop-out with the slot on the head.![GOPR2706.MP4_snapshot_10.54_[2015.10.13_19.59.41]](http://blog.gcawood.com/wp-content/uploads/2015/10/GOPR2706.MP4_snapshot_10.54_2015.10.13_19.59.411.jpg)
From here there are 4 screws easily accessible that can be loosened.
![GOPR2706.MP4_snapshot_01.24_[2015.10.13_19.57.57]](http://blog.gcawood.com/wp-content/uploads/2015/10/GOPR2706.MP4_snapshot_01.24_2015.10.13_19.57.57.jpg)
A black rubber seal is then visible, which comes off easily to reveal two white plastic mechanisms which are driven by a motor. Align the drive shaft (1) on the motor so that the point is away from the trimmer. Plastic mechanism [2] can come straight off. Plastic mechanism [3] drives the trimmer and has a shaft going down. It can now be lifted out.![GP012704.MP4_snapshot_00.53_[2015.10.13_20.09.58]](http://blog.gcawood.com/wp-content/uploads/2015/10/GP012704.MP4_snapshot_00.53_2015.10.13_20.09.58.jpg)
There’s a round rubber seal between the trimmer and the motor housing which must be removed. The trimmer must now be fully extended. With a bit of jiggling the trimmer will come out completely. There is a metal spring near the bottom which might catch, see below.![GOPR2705.MP4_snapshot_08.02_[2015.10.13_20.04.40]](http://blog.gcawood.com/wp-content/uploads/2015/10/GOPR2705.MP4_snapshot_08.02_2015.10.13_20.04.40.jpg)
The trimmer is unfortunately a sealed mechanism. The outer casing is two parts which look like they clipped into each other, but looks like some heat was used to ‘seal’ it. Anyway, I pried it apart, because there was nothing left to do. Not too much seemed to break.
![GP012704.MP4_snapshot_04.37_[2015.10.13_20.10.55]](http://blog.gcawood.com/wp-content/uploads/2015/10/GP012704.MP4_snapshot_04.37_2015.10.13_20.10.55.jpg)
When I opened it up it was clogged up with hair preventing it from moving. I cleared all of it up, and the cover fortunately managed to clip back together and seemed to hold.![GOPR2705.MP4_snapshot_03.06_[2015.10.13_20.02.47]](http://blog.gcawood.com/wp-content/uploads/2015/10/GOPR2705.MP4_snapshot_03.06_2015.10.13_20.02.47.jpg)
I don’t really know how to disassemble the razor further. There are two screws visible, but loosening them doesn’t achieve anything. Through the clear motor housing other screws can be seen connecting it to the outer case, but no way to access them.
![GP012704.MP4_snapshot_00.24_[2015.10.13_20.09.25]](http://blog.gcawood.com/wp-content/uploads/2015/10/GP012704.MP4_snapshot_00.24_2015.10.13_20.09.25.jpg)
I think the outer case is all just clipped together, but felt nervous in forcing it apart when I still want to use the razor. If my foils don’t make it in the post, then maybe I’ll do it, but for now I can’t see any further way to take the razor apart besides forcing the outer casing apart.
I have exactly the same one, great thing you did this now I have a reference when I want to disassemble mine.
Remove the front panel that surrounds the power button. It’s held on with double sided tape. There are 4 screws underneath.
Once that’s off – There are 4 more screws to remove the electronics from the housing.
Then 4 more screws to separate the black plastic from the clear, giving you access to the batteries and motor.
4 more screws remove the batteries and circuit board
Right on but some more details: It’s the larger, shiny black shell backing that peels off to reveal the housing screws, not the smaller, non-shiny piece just around the power button. A hot blow dryer blown onto the shiny black shell for about 10 min will loosen it without much picking at the seam. When you eventually take the bottom of the housing off, be aware there’s a plastic linkage arm that connects the white plastic cam pin that protrudes up. You’d be wise to photo both sides of the case as you begin to separate so you don’t forget how that small linkage arm is connected to the beard trimmer assembly on the back.
Run a hair dryer or portable heater on the area around the power button for approx 10-15 min and the larger, shiny, black plastic oblong cover will gently pry off with a guitar pick or toothpick. If the razor is not running, check the batteries for physical failure and check the wires to where the power cord plugs in. The wires are attached by tiny ring rivets and if are loose or spinning or moving, you’ll need to resolder the wires to the rivets. This fixed my razor. The batteries can be found on shopping websites but match the mA and voltage. Take a photo of the old battery positions, then take tweezers and when you pull or bend off the dead batteries, leave as much of the terminal clips attached to the razor motherboard as possible to make resoldering the new batteries easier. FYI, the two metal power pins in the power cord port are very durable, so a physically loose pin itself is unlikely. More likely the problem is a loose wire to the port. Also, when you take the razor apart there is a small black p-shaped plastic arm piece that slides into the the razor head and fits over the tiny black wheel pin on the other half of the razor when you rejoin them. The tail of the P inserts into a tiny slot in the head and the head of the P faces sideways and oriented internally.
The P piece may not fall out but be sure to fit it over the tiny black wheel pin on the other half of the razor when rejoining them.