Nokia 3720 classic stress test


To some extent, the review that we are going to present you today is unique. This time, we tortured a dust and water resistant cell phone – Nokia 3720 classic. The gadget is produced for those people who run a tight budget.

The retail package of the phone is standard issue stuff (Pic. 1, 2). The design won’t tell you much about the 3720 classic. It doesn’t feel like a phone that is able to survive in tough environments (Pic. 3, 4). But if you look closer you’ll see the evidence that it’s really a ruggedized device. The battery cover is locked with a screw. There is a strong rubber cushion between the metal lining and the rear panel. The rubber volume rocker is a part of the rubber frame surrounding the whole phone. The Nokia 3720 is extremely handy. The keyboard is comfortable to use. However, the volume rocker is stiff and has a low stroke. We had to press it with a fingernail. To release the battery cover is very easy, but you need to use a small coin to turn the screw. The Nokia 3720 classic measures 115 x 47 x 15.3 mm (4.5 x 1.85 x 0.6 inches), the weight is 94 g (0.2 pounds).

Despite the Nokia 3720 is claimed to be dust and water resistant, we didn’t make the test tougher.
Results

Pic. 1. Package box

Pic. 2. Accessories

Pic. 3. Nokia 3720 classic (front panel)

Pic. 4. Nokia 3720 classic (back panel)

1. Nokia 3720 classic stress test. Stage 1 — Light shocks

1.1 Drop test

We started with the drop test as usual. We successively dropped the Nokia 3720 classic on the carpet (video 1) with each face, edge, and corner from 1 m (3.28 ft) and on the tile (video 2) from 30 cm (11.8 inches). All in all, the phone fell for 6 times on each face, edge, and corner. The gadget showed no damage at all.

Video 1. Drop on the carpet from 1 m (3.28 ft)

The grade is 30 (with 30 being the highest possible grade)

Video 2. Drop on the tile from 30 cm (11.8 inches)

The grade is 30 (with 30 being the highest possible grade)

1.2 Squeeze test

In order to find out how the Nokia 3720 classic fares squeezing we placed it on a table and applied a 3 kg (6.6 lbs) pressure from a wooden bar above it (Pic. 5). This weight is too little to cause any visible harm. The phone successfully passed this test.

Pic. 5. The phone under the wooden bar

The grade is 24 (with 24 being the highest possible grade)

1.3 Bend test

Bend test is a different way of gadget’s torturing. But this occurs quite often. A phone that is placed on a rough wooden table may show a sign of bend if you apply some pressure above it. The approach is almost the same as in the squeeze test, but the phone should have different protective properties to stay safe. The casing should be sturdy or, perhaps, have some steel parts that make the handset rigid. Otherwise, the circuit board or the display may sustain damage.

In this test, we put the Nokia 3720 classic onto the two planks so that each edge of the phone lies on a single plank. Then we hitched a string with 1 kg load (2.2 lbs) on top of the device. The gadget showed no sign of bend and stayed functional.

The grade is 24 (with 24 being the highest possible grade)

1.4 Durability

In order to find out how the Nokia 3720 classic will look after a long period of everyday use and possibly abuse, we placed it inside a drum together with keys, pennies, and plastic balls (video 3). The drum was rotated at the speed of 500 rpm.

In 5 min we stopped the drum and took the phone out. We started to examine the Nokia 3720 classic and saw no visible damage at first. But when we took a close look at the phone in the bright lights we saw some scuffs on the metal frame around the body (Pic. 6). The phone also got scratched on the rear panel. However, we could see only the largest scratches as the matt plastic back cover made the minor scratches almost invisible. Few scuffs on the protective lens glass put it on par with the screens of the other phones that passed this test before.

Video 3. Drum rotation

Pic. 6. Scuffs on the metal frame around the body

Pic. 7. Scratches on the rear panel

Pic. 8. Scuffs on the protective lens glass

The grade is 15 (with 15 being the highest possible grade)

1.5 Scratch test

In order to check scratch resistance of the screen and the back panel we run them over with a nail fixed in a plank. The force of scratching was 100 g (0.22 lbs).

The matt plastic back panel made the scratch almost invisible again (video 4). The screen sustained no scratch at all.

Video 4. Back panel scratching

The screen gets 15 points (with 15 being the highest possible grade)
The back cover gets 15 points (with 15 being the highest possible grade)

1.6 High temperature

Nokia 3720 classic is a rugged phone. In order to check how it is capable of surviving in adverse conditions, for example, in extremely hot weather, we did the following: we placed the gadget in a metallic container 5 cm from the electric bulb (40 Wt). The bulb heated the phone for 3 min (video 5). The phone survived such test with no problem.

Video 5. High temperature test

The grade is 12 (with 12 being the highest possible grade)

1.7 Dust test

It’s time we performed a dust test. The Nokia 3720 classic is IP54 certified for dust and water-splash resistance. The 1st figure (“5”) stands for the ability of the phone to resist dust. Small grains of dust can penetrate the phone but the gadget will stay functional anyway. As for the meaning of the other figure (“4”), read further.

In this test, we took an enclosed tray containing dust and threw the Nokia 3720 classic inside it. We made it vibrate viciously for 2 min.

After the test we examined the device (Pic. 9). Few grains of dust penetrated under the lid that covers the connectors at the bottom of the handset (Pic. 10). But we saw no dust at all under the back cover (Pic. 11).

It was quite difficult to clean the dust out of the seams between the rubber cushion and the casing and between the keys and the casing. Even the brush didn’t help us to solve this problem. However, the sound quality stayed fine and the keys were still comfortable to use and did not produce any unpleasant noise.

Pic. 9. Here's how the gadget looked like after the test

Pic. 10. Dust under the lid that covers the connectors

Pic. 11. No dust under the battery cover

The grade is 12 (with 12 being the highest possible grade)

1.8 Connectivity

This is the last stress test that we present you at the 1st stage of our review. Actually, we placed the Nokia 3720 classic inside a box. Then we foiled the box (the foil served as a shield) and made a 40 x 50 mm (1.57 x 1.97 inches) hole in it.
The signal quality stayed fine during the stand by. But when we made an incoming call the reception fell by one point (video 6). The phone successfully received all the incoming calls, by the way.

Video 6. Connectivity test

The grade is 15 (with 15 being the highest possible grade)

After the 1st stage of the stress test, the Nokia 3720 classic got 192 (with 192 being the highest possible grade)

2. Nokia 3720 classic stress test. Stage 2 — Tough conditions

2.1 Drop test

This time, we dropped the Nokia 3720 classic on the carpet from 1.5 m (4.9 ft) and from 50 cm (1.64 ft) on the tile (video 7, 8). The result was the same as in the previous drop test: the back cover still clung tightly to the phone. We saw no visible harm. However, after the drops on the tile the phone failed to produce a polyphonic sound. We decided to go on and find the reason after disassembling.

Video 7. Drop on the carpet from 1.5 m (4.9 ft)

Video 8. Drop on the tile from 50 cm (1.64 ft)

The grade for the drop on the carpet is 30 (with 30 being the highest possible grade)
The grade for the drop on the tile is 20 (with 30 being the highest possible grade)

2.2 Squeeze test

We increased the applied pressure to 10 kg (22 lbs). The phone showed no damage. We heard no squeaks. The keys stayed silent.

The grade is 24 (with 24 being the highest possible grade)

2.3 Bend test

We made the bend test tougher. The weight of the load was increased to 5 kg (11 pounds). The Nokia 3720 classic showed no sign of bend (Pic. 12).

Pic. 12. The Nokia 3720 classic showed no sign of bend

The grade is 24 (with 24 being the highest possible grade)

2.4 Durability

The only part of the Nokia 3720 classic that has a chrome effect is the metal frame around the body. It stayed attractive after the 1st stage of the durability test.

We increased the period of time of this experiment to 10 min. But the result was almost the same as in the previous durability test. The handset got scratched and scuffed a bit more but the appearance of the gadget was still fine.

The grade is 15 (with 15 being the highest possible grade)

2.5 Scratch test

We scratched the Nokia 3720 classic at the force of 300 g (0.66 lbs). It inflicted an average scratch on the back panel (video 9). The scratch on the screen was visible only in bright lights (video 10).

Video 9. Back panel scratching

Video 10. Screen scratching

The screen gets 15 points (with 15 being the highest possible grade)
The back cover gets 10 points (with 15 being the highest possible grade)

2.6 Freeze test

Not all cell phones stay functional in cold weather. The cold depletes cell phone batteries faster than usual. But some handsets perform in -20 °C (-4 °F) as fine as in moderate temperatures.

We took a box filled with ice cubes, placed the Nokia 3720 classic in it, and then placed the box in a freezer for 2 hours. The phone was left in speaking mode during that time. The temperature in the freezer was approximately -15 – -20 °C (+5 – -4 °F).

In 2 hours we took the phone out and examined it (video 11). The battery stayed absolutely full (100 %). The keys became stiffer but performed with no problem. The display started to malfunction, though. After the air drying the display performed fine again.

Video 11. Freeze test

The grade is 12 (with 18 being the highest possible grade)

2.7 High temperature

In this stage of the test, we increased the time of heating to 5 min. The gadget sustained no evidence of visible damage. But it was too hot to handle it.

The grade is 12 (with 12 being the highest possible grade)

2.8 Immersion in water

Let’s come back to the IP certification. As we said before, the Nokia 3720 classic is IP54 certified for dust and water-splash resistance. The 1st figure “5” stands for the ability of the phone to resist dust. The 2nd figure stands for the ability to resist water. “4” means that the phone doesn’t care about splashes, no matter the angle they come at.

But we didn’t check the Nokia’s water-splash resistance. We performed a tougher test – immersion in water for 1 second (video 12).

The phone stayed functional. All the electronic elements are secured by the strong rubber cushion between the metal lining and the rear panel. But the plastic cap that covers the connectors let water seep through. The connectors, the ear-microphone jack and the battery stayed dry, though (Pic. 14). The loudspeaker performed pretty fine. We could use the phone as if it had not been dunked in water.

Video 12. Immersion in water for 1 sec

Pic. 13. The connectors stayed dry

Pic. 14. The battery stayed dry

The grade is 30 (with 30 being the highest possible grade)

2.9 Dust test

We increased the time of this test to 5 min. The only difference from the previous dust test was the cap that failed to protect the connectors from dust (Pic. 15).

Pic. 15. Dust in the connectors

The grade is 12 (with 12 being the highest possible grade)

2.10 Connectivity

We reduced the signal by placing the 3720 classic in the box with a smaller hole: 20 x 20 mm (0,787 x 0,787 inches). Although the signal indicator displayed only 1–2 bars, the phone received all the incoming calls (video 13).

Video 13. Connectivity test

The grade is 15 (with 15 being the highest possible grade)

After the 2nd stage of the stress test, the Nokia 3720 classic got 219 (with 240 being the highest possible grade)

3. Nokia 3720 classic stress test. Stage 3 — The toughest conditions

3.1 Drop test

At the last stage of the drop test, we increased the height of the falls on the carpet (video 14) to 2 m (6.56 ft) and to 1 m (3.28 ft) on the tile (video 15).

The back cover opened after each drop but we easily put it back. We examined the Nokia 3720 classic after the test. The gadget showed no damage and stayed functional.

Video 14. Drop on the carpet from 2 m (6.56 ft)

Video 15. Drop on the tile from 1 m (3.28 ft)

The grade for the drop on the carpet is 30 (with 30 being the highest possible grade)
The grade for the drop on the tile is 30 (with 30 being the highest possible grade)

3.2 Squeeze test

At the last stage of the squeeze test, we put a 20 kg wooden bar (44 lbs) above the Nokia 3720 classic. This pressure is too little to cause any visible harm.

The grade is 24 (with 24 being the highest possible grade)

3.3 Bend test

We applied 10 kg (22 lbs) weight in our attempt to bend the Nokia 3720 classic. The phone showed a slight bend (Pic. 16). When the screen was downwards, the gadget sustained no sign of bend.

Pic. 16. Bend made by 10 kg (22 lbs) load

The grade is 24 (with 24 being the highest possible grade)

3.4 Durability

We placed the Nokia 3720 classic inside the drum for the third time and rotated it for 20 min.

The test didn’t make the phone look older. Although we saw many newly made scratches on the rear panel (Pic. 17), they didn’t strike the eye. However, the numerous scuffs and scratches on the protective lens glass (Pic. 18) and on the direction key made the handset unattractive. Besides the physical deterioration of the gadget, there was a strange sound. The battery didn’t cling tightly to the sides of the slot and clattered inside the phone when we shook it.

Pic. 17. Scratches on the back panel

Pic. 18. Scuffs on the screen

The grade is 10 (with 15 being the highest possible grade)

3.5 Scratch test

This time, we increased the force of scratches to 600 g (1.322 lbs). The new scratch on the back panel was a bit deeper than in the previous test (video 16). The third stage of this test inflicted a large deep scratch on the screen (Pic. 20, video 17). However, as you may see from picture 19, both scratches aren’t too evident. Even if you accidentally scratch your Nokia 3720 classic like this, there is no reason to buy a new phone.

Video 16. Back cover scratching

Video 17. Screen scratching

Pic. 19. Scratches on the back panel

Pic. 20. Scratches on the screen

10 points for the screen (with 15 being the highest possible grade) for the screen
10 points for the back cover (with 15 being the highest possible grade) for the back cover

3.6 High temperature

We increased the time of this test to 10 min. This is the maximum period of time of high temperature exposure. In the result, the display became dim but the phone didn’t melt and stayed functional. Some minutes later, the Nokia 3720 classic restored its original brightness.

Video 18. High temperature test

The grade is 12 (with 12 being the highest possible grade)

3.7 Immersion in water

This time, we dunked the Nokia 3720 classic under water for 20 seconds. But the results were absolutely the same as in the previous water test. Water seeped through the plastic cap but the connectors stayed dry. The battery stayed dry too. After the test we dried the gadget, though we could make a call without any fears even when it was wet.

The grade is 30 (with 30 being the highest possible grade)

3.8 Immersion in beer

Water is not a problem for the Nokia 3720 classic. But what will happen if we dunk it under beer? The immersion in beer lasted 10 seconds (video 19). Surprisingly, beer penetrated under the back cover but very little, though. That’s why the electronic components of the phone stayed safe. The beer also seeped through the plastic cap (Pic. 21) but the 3720 classic performed pretty fine.

After this test we washed and dried the handset.

Video 19. Immersion in beer for 10 sec

Pic. 21. Spots of beer under the plastic cap

The grade is 9 (with 9 being the highest possible grade)

3.9 Dust test

We increased the time of the dust test to 10 min. We got the same result as at the 2nd stage. However, we found out that the top side of the back cover that is near the camera lens doesn’t cling tightly to the body. That’s why it let the smallest grains of dust seep through. The battery stayed clean, though.

The grade is 12 (with 12 being the highest possible grade)

3.10 The keyboard

The keyboard is dust and water resistant. During all the stress tests, the keys performed perfectly and without any squeaks. All the keys are rugged except the D-pad that has chrome effect finish. The rubber volume rocker is less comfortable than the other keys but that seems to be a sacrifice to splash and dust resistance.

The grade is 15 (with 15 being the highest possible grade)

3.11 Connectivity

The signal strength of the Nokia 3720 classic varied from 1 to 3 points when it was in the box with a 15 x 15 mm (0,59 x 0,59 inches) hole. However, the phone received all the incoming calls.

The grade is 15 (with 15 being the highest possible grade)

3.12 Short circuit and overcharge

We started with the light shocks – short circuit of the battery charger. We took a forceps and made a 1 second short circuit of the power supply terminals (video 20). As we expected, the battery charger stayed absolutely functional after this test.

Video 20. Short circuit of the battery charger

The grade is 15 (with 15 being the highest possible grade)

We did the same with the battery: 1 second short circuit of the power supply terminals (video 21). The capacity of the battery didn’t go down much.

Video 21. Short circuit of the battery

The grade is 15 (with 15 being the highest possible grade)

In order to check the quality of charging process, we plugged the battery charger in the PSU and checked the reaction of the gadget to the increase and decrease in charging voltage (video 22).

The charging didn’t stop at 2 V, though it was impossible. That’s a bad result. When we tried to increase the voltage of charging till 8 V, the phone gave a warning that the charger was out of order.

Video 22. Increase/decrease in charging voltage

The grade is 10 (with 15 being the highest possible grade)

Finally, we found out how the circuit board of the Nokia 3720 classic withstands overvoltage. We took the battery out and plugged the PSU in the phone (video 23). At first, we increased energy supply till 7 V. The phone sustained no damage and stayed functional. The energy consumption was normal. Then we started decreasing energy supply. The gadget switched off at 2.6 V. That’s a very good result, perhaps, the best that we have ever seen. This proves that the battery life is quite long.

Video 23. Power supply increase

The grade is 15 (with 15 being the highest possible grade)

3.13 Disassembling

Disassembling turned out to be more difficult than we expected. It took us a lot of efforts to detach the front panel from the rear panel. Probably, the silver front frame deformed during the stress tests which made it hard to disassemble the handset.

At last, we took the Nokia 3720 classic apart (Pic. 22) and found the reason why the loudspeaker stopped working after the drop test. The real cause was the damaging of the jackplug that is connected with the loudspeaker. We were pleased to witness the absence of any evidence of water and dust inside the gadget. Each cell phone that we had tested before let dust and mud seep through. Water and beer also penetrate the phones quite often, but not the Nokia 3720 classic.

The engineers of the 3720 classic did a great job. They placed a rubber cushion between the connectors and the circuit board. If water or beer penetrated in the jets, the circuit board would stay dry anyway.

The circuit board occupies almost all the space inside the body (Pic. 23). Most of the elements are sputtered which prevents the circuit board from corrosion attack (apparently, the engineers admitted the possibility of water penetration).

In general, the build quality of the gadget is in keeping with the best traditions of Nokia. But why did the loudspeaker stop working? Is it an accident or a fault of the engineers? We really don’t know.

Pic. 22. The Nokia 3720 classic disassembled

Pic. 23. The circuit board of the Nokia 3720 classic

The grade is 15 (with 15 being the highest possible grade)

After the 3rd stage of the stress test, the Nokia 3720 classic got 336 points (with 351 being the highest possible grade)

Conclusion:
The rugged Nokia 3720 classic is a good value for money. It resists water, dust and able to survive some pretty extreme situations much better than the standard cell phones. If your 3720 classic gets dirty don’t fear to put it under running water but don’t wash it too rigorously.

The phone doesn’t let dust seep through. The keyboard performs pretty fine. The only thing that can suffer is the design of the phone. It’s easy to clean dust and mud in the seams between the front and rear panel but there is no need to bother about this much. When we disassembled the phone we saw no evidence of dust and water inside it. The circuit board stayed clean. However, water penetrated under the plastic lid that covers the connectors. The plastic lid is the Achilles’ heel of the Nokia 3720 classic.

The casing is quite durable. The protective lens glass is much better than that of the other cell phones. The thick plastic panels prevented the handset from being bended, broken and squeezed. On the other hand, the surface of the casing is soft. This prevented the phone from being cracked.

The results of the drop tests were disappointing because the loudspeaker stopped working and the battery started to clatter inside the slot when we shook the phone.

The Nokia 3720 classic survived all the tests and stayed functional. To witness how the gadget looks like after the stress tests, check out the video below.

Here’s how the phone looks like after all the tests (Pic. 24, 25, video 24, 25).

Video 24. Here’s how the gadget looks like after all the stress tests

Video 25. Here’s how the gadget looks like after all the stress tests (macro)

Pic. 24. The front panel of the phone after the test

Pic. 25. The back panel of the phone after the test


All in all, the Nokia 3720 classic gains 747 points (with 783 being the highest possible grade).

Based on a 100-rating scale, the Nokia 3720 classic gets 95 points.

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Nokia 3720 classic stress test, 10.0 out of 10 based on 1 rating

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    [...] casing. This is the third УrobustФ handset that we have ever tested in our lab. The previous were the Nokia 3720c and the Samsung [...]

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