Entertainment Technology IPS Dimmer Schematics

pogoattack

Member
Joined
Feb 11, 2008
Location
NYC
Howdy All,
I have a general request for any schematics or other service literature for these units. We have both IPS-DS-2403 20A dimmer strips, and IPS-DP-6003 50A dimmer panels. I have been able to solve most of our failures by swapping out IGBT components. I have had one success tracing the problem with the PCB of the dimmer card itself but it was relatively easy to find as it was a faulty resistor and transistor that controlled the gate of one of the 50A IGBTs.
My current problem is with an older IPS-DS-2403 20A dimmer strip. The card with the fault has a PCB screened with : E02-0025, 04-21-92. The IGBTs are miniBLOC style. The problem is that around 5% DMX this dimmer card will blink to an apparent level of full, then back to the 5% and repeat this cycle two more times, then output the commanded 5%. After the blinking, the dimmer card will dim up and down from there just fine. After being given the DMX command of 0% however, it will do the cycle of blinks as it passes by around 5% DMX. When I tried jumping to Full from 0% DMX the dimmer card will then dim down fine until the same 5% or so, and do its set of blinks. I took a look at the dimmed output on a scope and the blinks appear to be the dimmer card switching back and forth from the native Reverse Phase Control (RPC) and Forward Phase Control (FPC), finally landing on FPC. Going back to 0% resets the card back to giving RPC the ole college try.
The manuals I have indicate that the IPS dimmer card will switch from its preferred RPC to FPC if it determines it is dealing with an inductive load. I was using several different size resistive loads in testing, different wattage incandescent lamps. Does anyone have any knowledge how these dimmers sense and determine its dealing with an inductive load. Also does anyone know if these blinks are the normal result of it determining an inductive load?
Any help would be appreciated, thanks!
 

blalew

Active Member
Joined
Sep 9, 2009
Location
Waco, TX
If you need some spares, I have four of the ET IPS dim bars that you can have. They worked great for us but the room has been updated. contact me directly if you're interested, they're in Waco, TX.