1987 Toyota 4Runner Digital Dash has intermittent flickering problem?

I'm about at my wits end.. and wondering if anyone else has had this problem and how they resolved it... or if someone can tell me how to get it fixed. The dash lites are fine and then suddenly they start winking on and off... then they're totally off... wait a while and then they're on again. Have replaced the ignition switch (someone told me that mite do it). No change. Took the dash out and sent it to a place in Canada that troubleshoots digital dash problems... they certified it as A-OK. Put the dash back in and it's STILL doing the weird thing. Have had the wiring gone over... have even bypassed the ignition and tested the dash with a hookup straight from the battery. This is making me crazy!!! Any suggestions??? :-(