atcomsystems.ca/forum Forums Other TDM Phone Systems Executone-Isoetec Telephones & Systems M64s: black bars on display; handset/jack problem

On one M64 phone, the display only shows black bars across rows 1 and 3, and nothing on 2 and 4. Otherwise, this phone works fine. Is there a reasonably easy fix (or at least a workaround) for this?

Another M64 works fine for the most part, but its handset jack is apparently a little loose, and the cord must be pinned underneath the phone so the jack makes contact with the board internally. This works okay, but both handsets we have used on this phone go out at times. Replacing the handset (without disturbing the phone-end of the cord) fixes the problem, but temporarily. It is entirely possible, maybe even likely, that we are just using crappy old handsets (perhaps they were stuck in the closet for a reason?), but I'm wondering if the jack issue could have anything to do with the handsets before I try any others handsets on this phone.

Thanks in advance for any advice you can provide.

Did you try adjusting the display? (small black wheel, on the bottom edge of the phone)

and it sounds like the jack needs to be re-soldered on the main board...in the phone, for that connection problem.

Yes, but the display is showing black-box characters on those two lines -- that is, all pixels darkened. It does this from the moment it is plugged in, no matter what extension it's at.

As for the jack, I know that's what it really needs, but I'm really just concerned right now with not ruining any handsets.

The display problem could be a few things.It could be the ribbon cable connecting the display to the main board isn't seated properly.It could be a bad display.Fixing it depends on how comfortable you feel with taking the bottom cover off the phone and checking the cable connection.
As for the handset problem have you tried replacing the handset cord?They are a common cause of problems since they do move at the two ends of the cord.If its not the cord then it probably is the connector on the circuit board is loose or the pins inside the connector are bent down to far.

The display problem is most likely either a bad LCD module or a bad cable connection. Without seeing it it is hard to tell, but I would suspect that the ribbon cable is coming loose and needs to be re-soldered.
The jack connection issue is not uncommon as the jacks get pulled on all of the time. It is probably only a matter if time before the connection comes loose completely. It is not unlikely that you are damaging the handsets if the jack is ever shorting out.
Both of those phones sound like they could use my services

Wow, thanks for your quick responses.

I feel entirely comfortable with taking things apart, and even replacing parts to cobble together good pieces from bad items. I already removed the ribbon cable very carefully from the socket and tried to reseat it, but that didn't help.

The handset cord is brand new, so I doubt it's that. As for the pins, that's something I didn't think of, so I'll check. What's odd is that the two handsets in question will work again later on, so I'm really not sure what's going on with them. :confused:

My bad, I forgot that that is a push-in ribbon cable...
Virtually all cords and cables are now made in the far east. It would not be unusual to have one bad out of the box.
It is most likely just the jack shifting minimally from play on the cord. No matter how carefully you pin it down, if you snapped the connection, it is going to cut out now and then.

I have the handset issue here also .When the phone were manufactured a small amout of hot glue was used to glue that handset jack to the pc board. During repair and refurbishing I guess that glue is coming off. All I have done is open the phone and put a drop of Elmers gluse back on there and let it dry. Works almost every time

Okay, I checked the pins, and everything seems okay there. Pulled both phones apart completely and there is no obvious damage to either one, either on the handset jack or the display module.

Wiggling around the bad display's ribbon cable while plugged in to the system does nothing, though I have noticed the two black bars are what every phone displays immediately (and normally very briefly) when plugged in. This one just seems to get stuck there at POST for some reason, with the rest of the phone perfectly normal. I should note that the particular display was "transplanted" from another phone that had other issues, but it displayed fine on that phone, and was removed and replaced with great care.

"Goop" works better than Elmers :p just be careful to set the pins all the way in properly. As for the display, if the phone otherwise works fine, and if you try another ribbon cable and it stil does not work, I would bet that the display is shot. Those displays are generally pretty solid but they do sometimes go bad.