Genie screwdrive stopped operating in down direction

Here is what my Pro88 is doing now.

First, I uncouple the door from the screwdrive so the drive unit is free to run, or not run, as the case may be. First tap of the remote (or the hardwire switch) starts the drive unit running in the up direction. Second tap of the remote (or the hardwire switch) stops the drive unit. Third tap of the remote (or the hardwire switch) does nothing (i.e., the drive unit lays silent). Fourth tap of the remote (or the hardwire switch) starts the drive unit running in the up direction again, and so on.

BTW, the door has no optical emergency trip switches, so those can be eliminated/ignored as a possible culprit.

Is there a relay in the drive unit that triggers the unit to operate in the down direction when the remote or the hardwire switch sends the appropriate command? If so, is it a relay type that is readily available such that I can swap it out? I know the Pro88 is an old model and I have already gotten my money’s worth, but if swapping out a relay (or other readily available electronic part) gains me a few more years of operation, I’ll take it before I have to go through the trouble of changing the drive unit to something different, and adding those annoying optical emergency trip switches. I live in the center of town, so there aren’t any toddlers or pets who are likely to wander into my garage when I am closing my garage door.

Thanks in advance for any helpful experience/insight you might be able to share.

 

Hi, do you have the owners manual, is there any kind of limit switch at the head that should be telling the position of the door? Some pics of the opener maybe helpful.
Geo