If you have a McIntosh amplifier with a blank display that needs repair, this post may help. I had a McIntosh MA9000 integrated amplifier in the shop for a display repair recently with a display that was totally blank. The issue turned out to be something I’ve seen a couple of times now in MR-88 and MA9000 among others, and it may be a simple fix. McIntosh uses Vacuum Fluorescent Displays (VFDs) in many different components, typically as part of a small display board that is attached to the main front panel board. Sometimes a blank display results from a component failure on the display board itself, and you must replace the board. However, in a few cases there’s a simple issue and a simple fix.
Check the bottom edge of the VFD board. A bias trace runs along the bottom edge of the board below the VFD itself. If the front / center bottom cover screw installed was too long, it may have made contact with the bottom edge of the VFD display board cutting into the trace, as in the figure below. As a result, the screw shorts the bias to chassis ground and renders the display inoperative.
Sometimes the screw shorts the trace but doesn’t break it. In those cases removing the screw will restore operation. But if the screw severs the trace, the problem persists. If your McIntosh unit has a blank display, check the bottom cover screws. Removing and installing a shorter screw in that front/center position may resolve your issue. If not, you may need to repair the trace. Either way, repairing the trace is a good idea. Reach out via our service page if you need help!
