Jumpers on CFAG320240C-FMI-T


New member
I have a few CFAG320240C-FMI-T displays and I was wondering what the JDISPOFF and JOFF jumpers near the connector are doing ?
In the datasheet connector pins 19 and 20 are marked as Not Connected but I noticed that pin 19 is connected to the JBUSY1 and JBUSY2 jumpers on the PCB and pin 20 is connected to JDISPOFF and JOFF.
So I'd like some explanation what happens if Vcc or GND is applied into these and what is their function ?
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New member

Hi there! You can actually use a multimeter (with continuity checker) and see if these jumpers are connected to some pin of the SED, or, where they end up in general. After that, I'm sure it will be easy to understand.


New member
I had looked into the SED datasheet but didn't see any input pins there that could be related to this.
I quess the trace from JOFF and JDISPOFF goes somewhere to the driver chips. I couldn't find datasheets for the drivers yet as only thing that reads on them is "7086 L123". I hope that was correct as I don't have a display to check now.

Continuity test probably reveals where the traces are going but without datasheet that might not be very useful.

I was thinking that maybe Crystalfontz might know what the jumpers on their display are doing and what they are meant for. ;)

CF Tech

Perhaps in an application where (by closing certain jumpers) the standard display could be used to replace a competitive or obsolete display.

For standard applications, the data sheet lists the pins as "No Connection". Please leave them disconnected in your application.