Ballantine Model #5755A Electronic Signal Frequency Counter. Sold for parts or repair. This unit has been power tested and does power on but the display only shows a "6" or possibly a "b" along with a decimal. As far as we can tell, the display works, because when we power it down, a bunch of the other sections of the display power on.  This could simply be a matter of not giving it a source, but we're frankly not familiar enough with this to diagnose the problem or more fully test it. Power tested. As shown. From a closing laboratory. Free shipping.