MP-2 Front membrane Ribbon cable issue

[rnolan]

I gave my Friend MikeB one of my MP-2s.  Unfortunately, it had developed intermittent issues booting up which was being caused (I subsequently discovered) by the connection or lack there of, of the main ribbon cable which connects the front panel membrane switches etc. to the PCB.  The PCB end of the cable was a bit ratty, I tried cleaning the (very thin) connections but the socket was also not providing a firm connection.  So today he managed to fix it (well sort of).  He used a razor blade to expose some fresh wire (more like a trace in these ribbon cables) and inserted some wooden scewers to get a better connection to the socket and viola, it's working again  :whoohoo!: .  So next is to change the socket, not hard to source I suspect.  Judging by how clear the display is in the photo, it's one I replaced years ago when I bought it from a member in Sydney.  It's easy to displace the main cable when changing the display as the display cable runs through/under the ribbon cable so take care if you do replace a MP-2 display (which do dim over time).

[Dante]

Richard,

I am facing something like this.....I was playing my MP-2 and it was working fine until the display started shooting wonky weird characters. The unit was still working fine, but I couldn't edit any patches or even see which patch I was on because the display was really acting up.

Now, this is a blue display, aftermarket. I still have the stock one.

I opened up the MP-2 and immediately see one of the wires from the ribbon cable is loose. I connect it by hand and the display is instantly twice as bright, so that must be a wire for the backlight, or at least half of it. Either way, that cable looks bad, it's just the display cable tho. Probably not the one you're talking about.

I will try the old stock display soon,  but I'm no hurry...I'll follow up with what i find

[rnolan]

Hey Dante, good you fixed it  :thumb-up: .  I'm just trying to remember (as it was ages ago I changed out a couple of displays, was there one wire that need to be soldered?

[Gregg]

Interesting fix.  I noticed the v1.41 firmware in the MP-2.  If you do source a new socket, please post the part number for it.

I am still fighting with one of my brother's MP-2s.  It is a real challenge.

Gregg

[rnolan]

Hey Gregg, and many thanks for the 1.41 EPROM  :thumb-up: albeit MikeB busted a leg removing the one he had etc...  IIRC MJMP said the PCB socket is the same as in the MP1, though I don't know the part number.  I think it's a pretty standard item  :dunno: .  If we find out how to source one I'll definitely let you know.

[Dante]

Hey Dante, good you fixed it  :thumb-up: .  I'm just trying to remember (as it was ages ago I changed out a couple of displays, was there one wire that need to be soldered?

I did find one wire soldered to the back of my display. I forgot to connect it when I tested my stock display and it works fine without it  :dunno:

I fixed my display today - the one I had is FUBAR. It's the aftermarket blue display, so not really a surprise I guess. I think I got it from Matt Trull. I replaced it with what I thought was the stock one....but now I notice my goofy arrow character in this one, so it's probably aftermarket too(?) It's got the stock green backlighting....I coulda swore it was yellow, but  I'm sure I'm thinking about my Quadraverb

I split this topic off to a new thread

[rnolan]

Hey Dante, Quadverb displays work as well.  The ones MJMP got hold of were the ones with slightly strange characters (was it for the arrows?) so that's probably where you got that one from, and also where I got a few spares.  Interesting that your blue one went FUBAR, I remember when you put it in, years ago now.

[rnolan]

So update from MikeB, obviously the wooden skewer fix isn't particularly robust, apparently it managed the first move/relocation but not the next  :facepalm: .   
 
Some bits he told me: 
The cable at the front panel end (which you can't really get into) is part of the membrane switches (based on other membrane switch construction he researched) so you can't replace it. 
The socket on the PCB is old school (of course) and not used any more (he hasn't found one yet), moreover, they are only good for up to 10 insertions/removals.  So don't pull it out unless you HAVE to.  Probably I accidentally pulled it out when I changed the display? it's a long time ago.  It's easy to dislodge when you change the display as the display connector cable runs under it. 
It seems trying to clean the exposed ends (very thin silver allegedly) of the ribbon cable seemed to do more harm than good.  Apparently he spent quite a while carefully exposing some clean trace x 10 with a razor blade.  Very fiddly no doubt, but he got there.   

Next step is remove the PCB socket and attempt to repair it, i.e. bend the individual contacts so they "get a grip" as it were.  He thinks they maybe can be removed individually, squeezed and re-inserted?