My shaver fell and head assembly fell apart .need diagram to help assemble 8251xl model. Thanks

I'd try to google the make and model
Either that or take it to the store where I purchased it and ask for advice.

Changing the head on Arcitec models is very easy. It doesn't come apart like older models. For the Arcitec model you simply pull off the entire head assembly and snap on a complete new assembly. See diagram at the link below

http://shaveroutlet.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/f/i/file_34_1.jpg

You can purchase replacement heads for this model at shaveroutlet.com. See link below

http://shaveroutlet.com/shaver-replacement-parts/norelco-philips-rq10-arcitec-replacement-heads-p-353.html

If you need help assembling the head, you can view a video at shaveroutlet.com. See link below and scroll down for video

http://shaveroutlet.com/shaver-replacement-parts/norelco-philips-hq8-spectra-sensotec-replacement-heads-p-251.html

You will find a helpful video for assembling the shaver head at shaveroutlet.com. See link below and scroll down for video

http://shaveroutlet.com/shaver-replacement-parts/norelco-philips-hq9-replacement-heads-p-252.html

Replacement blades can also be purchased from this link if desired. They ship to UK

You will find an instructional video at shaveroutlet.com. Click link below and scroll to bottom of page

http://shaveroutlet.com/norelco-philips-hq9-replacement-heads-p-252.html

It sounds like one of the blades may be damaged or not seated correctly. Try turning on the shaver with the top flipped up. If it is not noisy with the top up you can assume that its a problem with the heads.
Take the heads out one at a time and turn on the shaver each time. You can then determine if one is a problem and which one.

If you need replacements, you will fin them at shaveroutlet.com. See link below

http://shaveroutlet.com/norelco-philips-hq9-replacement-heads-p-252.html

The head assembly (the part that flips up) for your model 7775X shaver si comprised of three components; the heads, the head holder and the retainer. These are always sold seperately and you can find them available at shaveroutlet.com. See links below.


http://shaveroutlet.com/norelco-philips-7700-series-cool-skin-head-holder-with-hinge.html

http://shaveroutlet.com/norelco-philips-7700-series-cool-skin-retainer-p-305.html

http://shaveroutlet.com/norelco-philips-hq177-cool-skin-replacement-heads-p-245.html

It sounds like you need a new "head holder". These often wear out over time and fall apart. You will find a replacement at shaveroutlet.com. See link below.

http://shaveroutlet.com/norelco-philips-spectra-sensotec-head-frame-with-hinge-p-329.html

I solved the problem finally. I discovered that the plate which has the 2 large threaded holes which carry the fixed cutter, had to be locked in behind 2 spring fixing points (on the body of the clippers) before inserting the tongue into the body of the shaver. When I first removed the plate I used a screwdriver blade to spring the tongue away from the body and the whole caboodle (4 pieces) fell out on the bench, so I didn't see how it was assembled. Thanks for your interest anyway.