Dimmer Electricity "bleed"

[Chris Pflieger]

Well, unless you want to go back to autoformer dimmers, there's always a couple of microprocessors involved.

Indeed.

Even the dimmer in question here has what is probably the start of widespread MCUs in lighting - the 8051. Which puts its design in the early nineties* - that's the beginning of my career.


* I checked: The schematic is dated 1991.

 

[JChenault]

Well, unless you want to go back to autoformer dimmers, there's always a couple of microprocessors involved.

Er no. The early SCR dinners and consoles worked with nary a microprocessor. ( IE multi scene preset consoles). Even the early early ‘computerized’ board used TTL logic and I don’t believe ( but am not certain ) did not have a microprocessor.

 

[RonHebbard]

Er no. The early SCR dimmers and consoles worked with nary a microprocessor. ( IE multi scene preset consoles). Even the early early ‘computerized’ boards used TTL logic and I don’t believe ( but am not certain ) did not have a microprocessor.

@JChenault and @Chris Pflieger Early memory consoles such as the British Thorn Q-file which morphed into the Strand IDM-Q with it's whining drum memory and two 44RU 23" (rather than today's 19") racks plus dedicated air conditioning to deal with the heat. I met my first IDM-Q in the fall of 1973 in Hamilton, Ontario and my second in 1977 when I relocated to the Stratford Shakespearean Festival's repertory theatre in Stratford, Ontario. I believe Stratford's IDM-Q was installed in 1970 with nary a microprocessor nor IC in sight. The actual dimmers in Stratford in 1970 were the British built JTM's in at least three wattage ratings; nary a microprocessor there either.
Posting from the wilds of Canada, north of Donald's walls.
Toodleoo!
Ron Hebbard

 

[JD]

" To diagnose: Plug the pack directly into a know solid power outlet with no extensions. . . ." Now, how does one FIND a "known solid power Outlet with no extensions."? Finding really clean power in a building full of electronics is MUCH easier said than done without a 59-61 Hz bandpass filter with really steep cutoffs and a BIG ground stake down below the water table.

Actually, the bandpass filter is not a good idea! STEVETERRY wrote about his encounter with a transformer that had a harmonic filter built in and how it raised havoc with a new dimmer system a while back. The best power source is one that offers little resistance or inductance. Often, finding an outlet that is close to a service panel for testing is the best.

 

[Jay Ashworth]

I've worked with, I think, that pack, and I'm gonna concur it's unlikely to be the DMX.

I might suggest opening the pack and looking for electrolytic caps that are popping on top.

If you see any at *all*, I'd pull the board out and shotgun every cap in the pack. Be careful about polarity, and go for equal or higher voltage and equal or higher temp rating, while trying to hit the capacitance pretty close or just a touch higher, and fit in the available space.

If you're not a solder guy, find one.

 

[JD]

I've worked with, I think, that pack, and I'm gonna concur it's unlikely to be the DMX.

I might suggest opening the pack and looking for electrolytic caps that are popping on top.

If you see any at *all*, I'd pull the board out and shotgun every cap in the pack. Be careful about polarity, and go for equal or higher voltage and equal or higher temp rating, while trying to hit the capacitance pretty close or just a touch higher, and fit in the available space.

If you're not a solder guy, find one.

Electrolytic caps are a high failure item. Even when whole, they gradually fade in value over time. When they fade in value in power supplies, they tend to pass a lot of ripple, which can throw the ZVC detector. If you are going to go the "shotgun" approach, they are the cheapest and most likely suspect.

 

[Olddog]

Are any of the outputs driving LED's or switch mode power supplies? I'm thinking zero cross problems or some random DVDT turn on. If these are older packs they may not like non symmetrical loading.

 

[teqniqal]

it's a suddenly new issue with this pack

Leads me to believe that this is an internal failure in the dimmer pack as opposed to an external wiring issue. That said, the OP should check to see if maybe there is some external wiring change that coincidentally happened at the same time. Ghost dimmer scenarios frequently arise form loose neutral connections and from shared neutral connections. It can't hurt (well, unless you forget to turn-off the power . . .) to check your power wiring connections on both the feeder side and the load side.