20-06-2013, 12:43 PM
(This post was last modified: 20-06-2013, 12:44 PM by camallison.)
Readers may recall I also bought a Warf transistor tester before one of these. The display on that doesn't have a back-light and, after taking delivery of the small tester with backlight, I immediately modified the bigger one. It was a simple mod, taking a supply and logic signal through a MPSA 14 darlington transistor to a specific connection on the display board (pin 15 IIRC) and now it has a the backlight. The display board is very similar to that one the small tester has and so the facility is possibly available with a bit of judicious probing.
On the modifed board, I connected pin 16 to ground, emitter of the transistor to pin 15 and collector to battery positive. When the display turns on it produces a logic high which in turn switches the backlight on via the transistor.
Colin
On the modifed board, I connected pin 16 to ground, emitter of the transistor to pin 15 and collector to battery positive. When the display turns on it produces a logic high which in turn switches the backlight on via the transistor.
Colin
