UniProbe - Front panel

Parent Category: Tools Category: UniProbe - an UNIBUS signal adapter Written by Administrator

All 56 UNIBUS signals are shown by diagnostic LEDs on card front. Also supply powers are routed out for easy testing.

uniprobe3d leds

The LEDs are of 1.8mm type, these fit in the 100mil grid. They should be mounted looking vertical out of the case, this needs a 3D printed mount:

uniprobe leds


The 3D model for the mount are attachements on this page.


When viewing onto the card front from outside the PDP-11 card cage, we see these indicators:

1. Far left power connector:

uniprobe3d front power

2. Left half of LEDs:

uniprobe3d front leds left

3. Right half of LEDs:

uniprobe3d front leds right

These LEDs ares not just to have a light show. Dead bus driver may cause constant "active" levels, these are visible immediately.

Also an open "GRANT" chain shows up immediately by "active" BG* signals.

The LED drivers are analogous op amps, the LEDs show the voltage level ... which may be of some use. Input impedance is very high, so an open signal input may cause irregular flicker.

Most LEDs are lit on "LOW" voltage on the bus, as this is defined as "active" or "asserted". Only BG4,5,6,7,NPG light on "High".