Eta 251.262

[Specializedjim]

Hi all

recently purchased a Longines with a Eta 251.262 non working movement. After a quick look around I have managed to get the watch itself working but only the minute recorder on the chronograph works, I get nothing from 1/10 or second recorder. I know these movements are not that expensive to replace but I just wondered if any one has an idea of what’s wrong. Is it simply they are electronic and there is nothing to be done?  Thanks as always. 

[rodabod]

These usually operate as independent circuits. Is the 1/10 train free? Advance it with a fine oiler to check. It will likely have its own coil which drives its own stepper motor. 

[Specializedjim]

Hi. Yes all running free and I have changed the coil for a known good one. 

[rodabod]

Ok. I’m more familiar with Seiko chronograph circuits, but is it easy to check the condition of the switch terminals? On the Seikos there is a very fine layer of what is basically PCB track which forms the switch terminal and this can deteriorate. 
 

If you have the ability to, then obviously you could measure the voltage across the coil while it is active. 

[Specializedjim]

Hi the terminals look ok and when I put the battery back in only the minute recorder calibrates the others don’t move. 
 

Am I right in thinking I can’t measure the voltage across the coil with a standard multi meter, as that’s all I have. 

[rodabod]

It depends on the multimeter. You may still be able to detect the pulse in terms of voltage. What is more difficult is measuring current draw since it is in the microAmp range, but you don’t need to be concerned too much with current drawn yet. 
 

Maybe see if you can detect a voltage across the coil of the working sub-dial. Although it would be a pain having to wait a minute for every pulse. Unless you could switch it to zero-ing mode and set it flying around. 

[Specializedjim]

Thanks for that. I think I’m getting no signal to the coils. I guess that means it’s the control board and I would be better off getting a new movement. 

[Tudor]

Sometimes replacement boards can be had, if the rest of the movement is in good shape. 

[Specializedjim]

Many thanks for your help.