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Accutron tuning fork 218 and 224

HectorLooi
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HectorLooi Distinguished Member

HectorLooi

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I've been working on a couple of Accutron watches all this week. Both of them are non-runners from a watch lot I bought last year. Both of them qualify for the 404 club.

The first is a 218. The caseback wS missing and a whole lot of stuff got in. The coils tested ok but I suspect the transistor is the culprit. I am planning on replacing it with a 2N2222, SOT23 transistor. 

20210609_202938.thumb.jpg.2398c2446583dd55e87c29af904fae80.jpg

The second one is an Accuquartz 224. There is a hum when I tested it but the hands won't move.

20210613_174049.thumb.jpg.2788181cf5cd536e6f549cfd51d9b073.jpg20210609_213707.thumb.jpg.ff6c30546dedb21674d2486cc7998089.jpg

I've cleaned up both movements but I just figure out how to get the capped jewels out. They look like novodiac type jewels but are so tight that the ring doesn't turn.

I need the help of you Accutron experts out there. Is there a special tool needed for these?

 

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HectorLooi Distinguished Member

HectorLooi

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17 hours ago, Nucejoe said:

  Hi Hector, following your thread with interest, specially how you phase the watch.

Hopefully it be a lesson if members with experience join in.

Good luck .

I was hoping that with your vast servicing experience that you would be able to tell me how to do it. 😥

I've read all the instructions for phasing the 218 and 224. I have the Accutron test meter but I don't have the 224 movement holder with the IC phasing test probe. I can't seem to find any good photos of this test probe. I can't tell from the blurry photo in the 224 service manual whether it is a simple probe connection or whether it has a bias resistor connected to it.

I've tried phasing it by connecting the +ve and _ve leads of the Accutron meter to the movement. I can get the index wheel to run but I can't get it to "run-stop-run" as stated in the Bulova service manual.

Tonight I'll try balancing the forks first, then connect the +ve test clip to the test point and see what happens. Wish me luck! 🤣

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HectorLooi Distinguished Member

HectorLooi

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I balanced the tuning fork last night. I removed the gear train and just applied power to vibrate the fork. I adjusted the "regulator weights" until I got the oscillator to run with minumum current.

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I then put back the gear train and proceeded to phase the watch as per the instructions in the Bulova service manual. This time I managed to get the index wheel to run-stop-run. Hopefully the watch is phased correctly now.

I did try connecting the spare +ve lead wire from the Accutron test meter to the test point on the IC. But the meter needle went off the scale and I aborted. 

20210619_191109.jpg

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JohnR725 Distinguished Member

JohnR725

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On 6/17/2021 at 6:36 PM, HectorLooi said:

I've cleaned up both movements but I just figure out how to get the capped jewels out. They look like novodiac type jewels but are so tight that the ring doesn't turn.

even though the manual says that you're supposed to take the capped jewels out I'm reasonably sure In later generation you just leave them on. it's why when you look at the bottom of them there the openings which allow the cleaning fluid to get in and out.

On 6/18/2021 at 10:03 PM, HectorLooi said:

I've read all the instructions for phasing the 218 and 224. I have the Accutron test meter but I don't have the 224 movement holder with the IC phasing test probe. I can't seem to find any good photos of this test probe. I can't tell from the blurry photo in the 224 service manual whether it is a simple probe connection or whether it has a bias resistor connected to it.

one of the problems with phasing is that it assumes that you have a Mercury battery? I have a link below it explains how to correctly phase a watch for the higher voltage silver cells. The method works really well.

then you no longer need the adapter for the 224 as it's explained at the very bottom of the page at the link below.

then I'm reasonably sure that there's a resistor in the adapter. Conveniently at spray-painted black C can't see it but I vaguely recall that there is one in their I would have to find wine to look and see.

http://members.iinet.net.au/~fotoplot/accphs.htm

 

 

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HectorLooi Distinguished Member

HectorLooi

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20210704_144524.thumb.jpg.89aefa009f10422993d0cd90192d8eae.jpg

I managed to get the 224 up and running. It has been 3 days and it is fast by just a second. Not bad for a 404 club watch!

I resoldered the components of the 218 back into the watch and it started humming again. Looks like it was a case of cold solder somewhere. Hmmm... what am I going to do with the 100 2N2222 transistors that I ordered? 🙄

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Alastair WRT Addict

Alastair

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If intermittent humming, Itll be one of the coils--Winding intermittent o/c.

Had this a few times--Trick is finding it stopped to determine which coil! Ive got one exactly like that at the moment, but everytime I dcheck--it starts up and hums. Guess I'll have to do a substitution on it..

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HectorLooi Distinguished Member

HectorLooi

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44 minutes ago, Alastair said:

If intermittent humming, Itll be one of the coils--Winding intermittent o/c.

Had this a few times--Trick is finding it stopped to determine which coil! Ive got one exactly like that at the moment, but everytime I dcheck--it starts up and hums. Guess I'll have to do a substitution on it..

Would the coil resistance reading give any clue as to which oe is broken?

I read that there are people specializing in recoiling Accutron coils. Have you found anyone able to that?

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