Problem during install of new tact switch

Hi everyone,

I tried to solder in a new tact switch for my down arrow this evening on my MPC1000. I was able to desolder + remove the old tact switch and solder in the new one with no issue, but while I damaged the blue ribbon connector to the bottom left corner of the PCB with the tactile switches.

Here's a picture :



I'm able to power on the MPC & the OS loads, but the buttons are not working correctly. Only the stop, start, next bar/last bar buttons are working consistently.

What can I do to diagnose this problem? And fix it?

-M

Hmmmm. The best way is to replace this flex cable with new one, but I think it will be expensive to get it original (maybe somebody could sell it from broken MPC) So you can buy the other flex (e.g. in electronics shop)with the same number of wires inside or more and cut it to the same lenght and widht. It should be 20 wires as is it on the picture. You can also solder thin wires directly to the PCB if You can do it yourself. There are really many ways to make it work. BTW, does the cable is not damaged on the upper edge (or shifted) as seen on this picture? Maybe You should put the cable in the connector closer to the other edge(to the right when you look to front of CNT)

Thank you so much for your reply! I'm a little despondent about breaking my MPC...

So, I'd need a part like this, I guess? :

http://www.ebay.com/itm/20-pins-1mm-pit ... 500wt_1086

I did notice that the flex cable was stiffer on the left side (top side in the picture). I had to really work to get it in there. You think I should try moving the cable to the right in the slot (toward the bottom in the pic)?

Where does the other end of the flex cable connect? Do you know what function it serves? Also, is there any chance that the tactile switch I soldered in could be affecting the machine? I think I did a pretty clean job on it, but it would be good to be sure that the flex connector is the problem.

-M

Yes, this is right part but I think it needs to be longer. I`ve checked the service manual and the part number for this cable is: EW - 821887X CORD FFC P1.00 L210 20P . If the lenght is in milimeters there so you should look for another cable - 210mm long, of course it can be longer.

The other end of the FCC is connected to the PC Block (mainboard) so you need to get there.

The functions are listed on the diagram in the service manual (J102 on the left side)


You asked me about tact switch. I don`t think it can affect the working of MPC, even if it is normally closed.

I`m not sure is there a short circuit on the flex where you burn it by the soldering iron but I think it would be best if you could replace it with new one because it could be broken at the end (as it looks on the picure).

This part is also available here but unfortunately there isn`t picture of it http://www.mpcstuff.com/1a821887x.html

Thanks, that's very helpful. I tried pulling the FFC further to the right in the slot and (miraculously) it began working. I may have to replace it in the future if it begins misbehaving...so it's good to know that I've identified the right part.

Could you send me a copy of the service manual? It would be nice to feel slightly less blind when I open her up!

-M

The manual is here http://www.sendspace.com/file/9rplrr

I'm glad I could help you.