ESA 942.711

[LexLuther]

Hi all, I'm wondering if anyone has any experience with the ESA 942.711 digital movement and can help me figure out what's causing it to not work?  When I received it it was obvious there was a battery leak at some point. The battery connection (see photo) has corroded and fell off, so I soldered a new connection using a led leg.  After removing the black plastic cover to have a look at the IC (I think that's what it's called) I found some more corrosion. Iv'e attempted to repair the corrosion and cleaned it up.  For some reason I can only get  numbers on the lcd when I melt the solder on each solder spot on the top of the board. Then if I remove the batteries and put them back it it disappears again. I'm trying to figure out why heating up the solder joints gets the lcd semi working  

[ecodec]

6 hours ago, LexLuther said:

Hi all, I'm wondering if anyone has any experience with the ESA 942.711 digital movement and can help me figure out what's causing it to not work?  When I received it it was obvious there was a battery leak at some point. The battery connection (see photo) has corroded and fell off, so I soldered a new connection using a led leg.  After removing the black plastic cover to have a look at the IC (I think that's what it's called) I found some more corrosion. Iv'e attempted to repair the corrosion and cleaned it up.  For some reason I can only get  numbers on the lcd when I melt the solder on each solder spot on the top of the board. Then if I remove the batteries and put them back it it disappears again. I'm trying to figure out why heating up the solder joints gets the lcd semi working  

Hi, I have never had one of these in. However it appears from your photo that the LCD is powered through an elastomer flexible contact strip. If this is the case then remove the elastomers and thoroughly clean them in Isopropyl alcohol and the glass contact area as well. If this is the problem then this treatment should cure it. Careful with that soldering iron !!!! Regards, Mike. PS. You may need to put a small insulator under the -ve battery terminal ??

 

Edited June 27, 2018 by ecodec
More info.

[LexLuther]

21 hours ago, ecodec said:

Hi, I have never had one of these in. However it appears from your photo that the LCD is powered through an elastomer flexible contact strip. If this is the case then remove the elastomers and thoroughly clean them in Isopropyl alcohol and the glass contact area as well. If this is the problem then this treatment should cure it. Careful with that soldering iron !!!! Regards, Mike. PS. You may need to put a small insulator under the -ve battery terminal ??

 

Thanks for the reply. Iv'e cleaned the flexible contact strip before. I was going to give it a better clean, but Iv'e just ruined it. Iv'e accidentally knocked a few wire bonds off of the chip, lesson learnt  I'm going to try and repair it, although it's going to be like doing surgery on an ant. I'm not even sure what glue to use?

I'm interested in knowing what the insulator does?  

[ecodec]

3 hours ago, LexLuther said:

Thanks for the reply. Iv'e cleaned the flexible contact strip before. I was going to give it a better clean, but Iv'e just ruined it. Iv'e accidentally knocked a few wire bonds off of the chip, lesson learnt  I'm going to try and repair it, although it's going to be like doing surgery on an ant. I'm not even sure what glue to use?

I'm interested in knowing what the insulator does?  

Normally it stops the -ve battery contact shorting out.