Ronda Caliber 3540.D

Brand	Ronda
Caliber Number	Ronda 3540.D
Type	Quartz
Lignes	10 1/2”’ x 11 1/2”’
Diameter	26.2mm
Thickness	4.9mm
Battery Cell Number	384 (1.5 V)
Claimed Battery Life	54 months
Jewels	5
Hacking	Yes
Hands	1.50mm / 0.90mm / 0.25mm
Hand Count	6
Functions	Central hours and minutes, central chronograph seconds, 30 minute counter at 9:00, 1/10 seconds and 10 hour counter at 12:00, small running seconds at 6:00, date at 3:00
Country	Switzerland (Swiss parts version also available)
Known Models	Wenger Swiss Military Classic Active Chrono (add yours in the comments)

The Ronda caliber 3540.D is a quartz chronograph from Ronda’s startech line of watch movements. This caliber has subdials at 6:00, 9:00 and 12:00. Technical documentation for this caliber was found dated as far back as May 9, 2009. Tech drawings are shared with Ronda caliber 3520.D.

Swiss Made VS Swiss Parts:

According to the Ronda website, there are two versions of this movement: a gold plated Swiss Made version and nickel plated Swiss parts version. They both have 5 jewels. Ronda also considers this movement to be repairable.

Power Saving Feature

The battery is claimed to last about 54 months in normal conditions, but if you are not going to wear your watch for a while, the 3540.D has a power saving mechanism when the stem is pulled out stem (aka hacking function). Reduction of battery consumption approximately 70%. It is not advisable to leave the chronograph second hand running because it will drain the battery faster and put more wear and tear on the gears.

Accuracy:

According to Ronda, the caliber 3540.D should keep time within -10/+20 seconds per month with an operating temperature of 0 to 50 degrees Celsius.

How to change the battery:

There are two screws holding the battery cover down. Carefully remove the two screws (don’t lose them!) and lift the battery cover off.

Replace the battery with a 384 (often packaged as 392/384) cell.

Put the battery cover back on, do not fully tighten the first screw until the second screw is in. Make sure the orange insulator tab is in place.

Resetting the Chronograph to Zero:

After changing the battery, your chronograph seconds hand or subdial totalizers may not be not lined up to zero. You can use the following sequence to get everything lined up:

1. Pull the crown out two clicks to time setting position (position III).
2. Press button A (top chrono button) and B (bottom chrono button) together for at least 2 seconds.
3. The chronograph seconds hand will spin around one full turn, this is how to know you’re in correction mode.
4. Press button A to advance the main chrono hand forward until it gets lined up. Long press to make it advance faster, short press for one second intervals.
5. Press button B to go to the next hand.
6. Press button A until the hand is lined up.
7. Press button B to advance to the next hand.
8. Press button A until the hand is lined up.
9. Press the crown back in to position I.

Note: In the unlikely situation that the hands still won’t line up, or if they are moving around, there is a chance the hands are loose and need pressed back on.

The video below is not of a watch with a 3540.D movement inside, but it is a similar Ronda chronograph and can help you get an understanding of the process to reset your chronograph hands to zero.

Chronograph Pushers:

The pushers on the 3540.D are controlled via the plastic movement holder as pictured below.

On this particular watch, you cannot engage the chronograph function without the movement holder installed. A movement holder or spacer, such as the white plastic example shown, is often found on larger watches. Smaller timepieces may not need a holder/spacer and possibly have the chrono buttons integrated into the case design. If your watch is like that, please post it in the comments.

If you remove the holder for any reason, make sure the metal prongs don’t fall out. When putting the movement holder back in the case, you may need to slide the metal prongs back and forth so that they don’t catch on the case or the chronograph button tabs on the movement.

Stem Removal

To remove the crown/stem, find the hole with the arrow. While the crown is in position 0, pressing this with your tweezers or other tool will allow the stem be unlocked so you can pull it out. Do not press too hard.

Replacement Price:

At the time of this post, replacement prices for the Ronda caliber 3540.D were found online in the range of $46.65 (wholesale) to $59.95.

Watches With This Caliber:

The caliber 3540.D below was found in a Wenger Swiss Military watch here. Please add your watch to the comments below.

Additional Resources:

• Official 3540.D datasheet