Twemco QT-30 creeks between minutes - normal?

[LTNine]

Hello everyone!

I just got my first flip clock about a couple weeks ago, the Twemco QT-30. The minute seems to flip over +/- a few seconds between each minute. For the life of me I can't seem to get it to flip over at the exact time. I get that computers are not even accurate, and NTP servers constantly correct them (millisecond or less differences). So losing small amounts of time is going to happen. But the specs say 1.5 seconds per month. What concerns me is:

- It makes little creeks (twice) in-between the minute.
- After a week from the first time setting it, I noticed it was around 10 seconds late.
- When I reset the time, the usual 120 second delay from the first time actually took 145 seconds (you're supposed to set it 1 minute ahead and it catches up).

When I first got this clock it was more of a "fun" clock to get for my desk working from home. I did not expect to fall in love with flip clocks. My ability to keep track of time is so much better, and the reminder of an hour passing is much more pleasant than other methods I've used in the past. I much prefer them over a ticking clock. So when I saw a Twemco BQ-170 new for half MSRP, I jumped on it. For the kitchen.

The BQ-170 is dead silent and changes minutes on a dime. Which makes me question whether what the QT-30 is doing is normal. I get that the QT-30 is "consumer" and the BQ-170 is "commercial" so it could very well be a consequence of cheaper vs more expensive parts.

So I searched around and found myself here. To find other people who know much more than me on the subject, and whether I need to fix/clean the QT-30, and if so the proper way to go about it.

[RetroFlip]

Hi, you might look at what Johan did recently on a similar clock when it was running slow. twemco-bq-50-running-slow

[Johan de Jong]

Creeks between the minutes is something I cannot explain. I don't know how the QT-30 works, I only know the BQ-50 but would expect them to be similar. The BQ-50 uses an electronic quartz controller to switch on the motor very briefly once a minute. That is the only mechanical thing that happens each a minute. In between it is just sitting there doing nothing. So if some creaking is happening in between I guess it must be a different mechanism.

Regarding the timing I think I found out that in the BQ-50 there is this trimmer capacitor that you can use to fine tune the speed. If the QT-30 has that as well you could try that (make sure you record the current position before adjusting it so you can always go back).

[flipoclock]

I have a really large Twemco flipclock (mains powered) on my workbench for awhile, it's actually hanging from the wall for else it will not run properly and it also have a sort of creek between minutes. I suspect it is wear and tear, but have not been able to find a real cause for it is somewhat difficult to delve in the clock when it is hanging on the wall.

[LTNine]

I took the back off the QT-30:



And here's a video:

The creaking can be heard at 0:20, 0:40, and 0:52 where it sounds like it wanted to flip, but doesn't actually turn over until 1:04.

I've observed it with the back off, and I don't see anything catching or anything obvious.

Creeks between the minutes is something I cannot explain. I don't know how the QT-30 works, I only know the BQ-50 but would expect them to be similar. The BQ-50 uses an electronic quartz controller to switch on the motor very briefly once a minute. That is the only mechanical thing that happens each a minute. In between it is just sitting there doing nothing. So if some creaking is happening in between I guess it must be a different mechanism.

Regarding the timing I think I found out that in the BQ-50 there is this trimmer capacitor that you can use to fine tune the speed. If the QT-30 has that as well you could try that (make sure you record the current position before adjusting it so you can always go back).

Yeah, the mechanism is different. The wheel on the left "ticks" every second. You can hear it in the video, but it's inaudible unless you put your ear up to it. I think my BQ-170 works very much like the BQ-50. It's dead silent until the motor kicks in.

Is your motor this loud?

It's very hard to find videos of these clocks without music covering up the actual sound of the clocks. One video I did see of this clock was it switching everything over at midnight, and that one I couldn't hear the motor but the loud "thunk". Mine made the "thunk", but I could hear the motor thru it. Just wondering if this is normal. It's very accurate though!

[Johan de Jong]

The mechanism between the minutes and hours looks the same as in the BQ-50, but the driving bit with the motor is entirely different. To know what is going on in there you would need to take it further apart, but I don't know whether that is possible.

For the sound I made two video's of my BQ-50 for the minute and the hour flip: