Is your Casio F-91W a fake?

Comparing a genuine Casio F91-W with a fake

The Casio F91-W - the sign of al-Qaida. Yes, really!

I've a bit of a love for Casio watches, and you can't get any more Casioey than the F91-W. I own a couple of them - I thought I'd lost one at one point so bought another. Then I found the original in a suitcase in the loft. Annoying.

I recently spotted this eBay auction:

eBay auction for a fake Casio F91-W

I had my suspicions... a genuine F-91W for £3.95 delivered? The 'proof' given by the eBay auction that this is an authentic Casio is that if you hold the right hand button down for a few seconds, CASIo appears on the display. Some early fakes didn't implement this little quirk, but surely the fakers got wise to it and implemented it? By way of comparison, a genuine F91-W from a reputable retailer is currently around the £10 mark. This one, for example, in Argos.

Curiousity got the better of me so I ordered it, and guess what...

It's definitely fake.

I've taken some photos below, comparing the genuine item with the fake. Note that the images are high resolution, so zoom in using your normal method in order to get a close-up look.

Genuine and real Casio F91-W

Let's look at the face first. The genuine is on the left and the fake on the right. Notice how clear the 'ALARM CHRONOGRAPH' writing is on the real item - you can barely see it on the fake. A tell-tale sign is the tiny 'u' in the bottom right of the face. To print such a small character requires a decent printing process. The fakers don't have a decent process so can't print tiny letters like that, so they've simply made the 'u' much bigger than it should be, in order that it doesn't end up as an unidentifiable blob.

An extra segment on the fake F91-W

With all the LCD segments visible, it's clear that the fake has added an extra segment, indicated with the arrow.

A tag on the fake Casio F91-W strap

The strap is a dead giveaway. The fake strap on the right has a horrible tag on it where it's been badly cut from a mould. You can't see any mould lines at all on the genuine strap.

Screws on a real and fake Casio F91-W

Let's flip it over and look at the back. Look at the screws on the genuine piece - they are Philips screws but they are cut out in one direction such that you could use a flat-head screwdriver to unscrew them. Nice attention to detail. The fake piece on the right has some much larger, Philips-only screws.

Genuine Casio F91-W circuit board Fake Casio F91-W circuit board

Let's look at the circuit boards inside now. They actually look fairly similar. Genuine on the left, fake on the right, as always. You can see that the plating on the fake board is poor - the contacts are nowhere near as shiny as the genuine.

Also worth pointing out here is the three solder blobs, highlighted in red. You can see how they're connected to the crystal. These will almost certainly be used to tune the crystal to get the watch accuracy spot on. Obviously no such tuning has gone on in the fake.

Rear of genuine Casio F91-W circuit board Rear of fake Casio F91-W circuit board

The rear face of the PCB is again as expected. Clearly the genuine on the left is a higher quality.

Genuine Casio F91-W case Fake Casio F91-W case

Lastly, let's have a look at the cases. On the genuine you can see that the buttons have been milled to a point on the end, whereas on the fake they've not bothered. The seal looks much cleaner and precise on the genuine and again you can see the horrible tag on the strap on the fake where it's been cut out of the mould.

So, at this point we're fairly sure that the eBay F91-W is a fake, right? Well, as if you needed any more evidence, this is the bag it came in:

Fake Casio F91-W packaging


Andy C
July 2018