Control/Dimming 1995/1996 Hub/Varalite houselight/wall panel control problem

Butch!

Member
A colleague at another school district is having issues with the houselight controls on their circa 1995 Hub/Varalite dimming system and asked me for help, but like most other people, I have very little experience with them and am hoping someone here does. Here's what they've got . . .

The school was built in 1995 or 1996 with a 96 dimmer Hub/Varalite dimming system, I think the nameplate calls it a 'PR96'. Dimmers have TTI stickers on them and there are two firing cards (1-48 & 49-96) and they are TTI as well. There are two other cards in there, looks like one has the transformers to monitor the phases and the other is the processor.

The last 13 dimmers in the rack control the houselights which are almost all 1K can lights. There are two preset slider wall controls (one in the booth, one backstage) and two pushbutton panic switches. The preset slider panels have 'off',' dim',' on' buttons on them, numeric keypads and then a master slider and three channel sliders. The system was set up so each channel slider controls a portion of the houselights. If you press the 'on' button or the panic buttons all 3 of the channels come on to full. If you press the 'dim' button then the sliders actually do something and you can set the look. No one knows what the numeric keypad does and there is no operator's manual anywhere. The stage lighting is controlled by an Express 24/48.

So here's the problem. One day they came in and hit the panic button ('on') to turn on the houselights and the houselights came on, but at less than 50%. They tried both slider panels, the 'dim' setting, the 'on' setting, etc, but all they get is less than 50%. Then they turned on the Express 24/48 and the houselights started 'flashing' going between maybe 30% and 60% in a steady rhythmic pattern. Turn the console off and they stop flashing. Brought in an Express 48/96 and the same thing happens, if there is DMX the houselights flash. If there is no DMX they are at somewhere below 50%. The rest of the dimmers all work fine and respond to the DMX from the Express console.

Put a meter on the houselight dimmers and they're only putting out 47.5 volts, didn't meter them while flashing. Incoming line voltage is around 117 on each phase. Took a look at all the cards and blew the dust off of them, no change. Have tried killing the system with the main breaker and letting rest, but no change. Pulled one of the slider stations and it looks like they are analog as there are over a dozen single #18 or #20 wires running from each station back to the rack. In the rack there is a separate area where all of the little wires from the stations hit a number of PCB boards which mainly have relays and empty relay/IC sockets. We assume that these boards are generating a signal which is going to an analog to DMX converter (or straight to the firing cards) and that something is going wrong in there. But with no manual and no schematics we can't be sure what's going on. For all we know some kid played with the numeric keypad and caused this. For now we've put jumpers on all the SSR's so the dimmers are now locked on and they turn the houselights off with the breakers.

Does anyone have info they can share?? This school system is extremely financially challenged (closing schools and selling the buildings to pay debt) and there's no way they'll find the $$ to replace the system.

Thanks for any insights . .
 
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Amiers

Renting to Corporate One Fixture at a Time.
Well it could be a power issue. You could test by pulling some of the cards or turning off the breakers on them and then running the house control.

It could be a slider issue on the panel that’s stuck open. And when the dmx tries to take control it’s fighting the slider for control thus giving you the bouncing effect.

It could be a control issue overall. Someone re-recorded the presets and then set a chase in the console to flash the house lights. ( this is unlikely unless you got some really smart kids that wanted to mess with you)
 

FMEng

Well-Known Member
Fight Leukemia
I disagree with Amiers. If the stage lights work properly and can be brought up to full together, then it is unlikely to be a power source issue. It was a good step to meter the incoming voltage, just be sure to meter it with lights on.

This seems to me like a control card issue, or possibly a failing DC supply for control section or the house light stations. Contact Lite-Trol Service at 800-548-3876. They might be able diagnose it over the phone.

If all else fails, I would go through the system and replace all of the electrolytic capacitors. They commonly fail due to heat and age. The equipment is certainly the right age for it. The ones near heatsinks should be suspected first. This is a very inexpensive fix, but it requires good soldering skills to avoid damaging circuit boards.
 
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Butch!

Member
Thank you everyone for your replies.

The voltage was metered with around 1/3 of the stage fixtures on and the dimmer rack is fed from it's own transformer which is 6' away so I don't think it's an incoming voltage issue. The IT department (who is in charge of the auditorium) says there have been no spikes or other power issues at the school.

The card cage under the dimmer modules which has the firing cards, what I assume to be the phase monitoring card, and the processor card all feed from a small switching power supply in the card cage and it was checked and is putting out the nameplate voltage. I hadn't thought about a separate power supply for the wall stations and it sounds like a good lead. The cards which control the wall stations are in a separate attached cabinet which also houses the breakers which were intended for constant circuits in the auditorium, but never used. All the load wires pass through this cabinet on the way to the dimmers and it is a mess of unmarked low voltage wires and a few cards most of which have small relays inserted in IC sockets and some empty sockets. I'll have to look more closely at this section and find the power supply.

Heat damage to the capacitors is also an interesting lead as the cooling fan quit a few years ago and wasn't fixed for over a year as the service provider that had an annual maintenance agreement on the system and "serviced" it every six months didn't notice, even after the school complained that dimmers were stuck on. The modules above the houselight dimmers got so hot the SSR's started leaking and turned on. The school got a new HVAC tech and while he was checking out the school he noticed the fan didn't work, fixed it and that problem went away.

The school is located in the middle of nowhere, Pennsylvania. The IT guys called the closest service provider who apparently told them that if it is a Hub it can't be fixed and to get a new system.

Really hoping someone out there has a schematic or a manual. I work on electronics all the time and could figure it out if I had a map.

Thanks again!
 

Butch!

Member
Do you have a photo of the numeric keypad and wall sliders?

Why yes, yes I do . . .

Though these were taken before the troubles started, so any LED's (or lack thereof) aren't reliable.

Thanks !!!

keypad station.JPG
rack interior.JPG
 

FMEng

Well-Known Member
Fight Leukemia
That looks suspiciously like a regulated power supply module at the left of the bottom shelf. It appears to have several outputs. It's probably an off the shelf supply made by another manufacturer. That supply might be just for the rack, or one of the rails could feed the house light stations. In any case, I would check all of the supply rails for DC value and AC ripple.

I know that in that era, Strand powered their house light stations from a power supply built into an electrical junction box. As I recall, it was nothing more than a transformer and a fuse. The rectification and filtering was done on the main house light controller board. Of course, Hub could have done it completely differently.

The rack has a filtered air intake on the bottom. Are there exhaust louvers on top covered by the box, or is the air supposed to leak out the cracks around the dimmer modules? How are the rack fans?
 

Butch!

Member
Door closed.JPG
That looks suspiciously like a regulated power supply module at the left of the bottom shelf. It appears to have several outputs. It's probably an off the shelf supply made by another manufacturer. That supply might be just for the rack, or one of the rails could feed the house light stations. In any case, I would check all of the supply rails for DC value and AC ripple.

I know that in that era, Strand powered their house light stations from a power supply built into an electrical junction box. As I recall, it was nothing more than a transformer and a fuse. The rectification and filtering was done on the main house light controller board. Of course, Hub could have done it completely differently.

The rack has a filtered air intake on the bottom. Are there exhaust louvers on top covered by the box, or is the air supposed to leak out the cracks around the dimmer modules? How are the rack fans?

Yes, that is a power supply, it appears to be a replacement for the original one. It only feeds the card cage and has checked out as OK. The houselight controls are located behind the breakers on the right side of the rack in the pic above. The cards are mounted to the wall between the breaker section and the dimmer section. The installer ran all of the load wires through this area and the main feeds are in there as well so it's a mess and hard to see everything. I didn't see a separate power supply in there, but I wasn't thinking along that route at the time, but it's making a lot of sense that there probably is one and that it is failing.

There is a fan behind the air intake which forces air up through the modules then it is supposed to leak out through the front of the modules and through the expanded metal in the door. The pictures were taken a few years ago and I removed the box and nicely asked the custodians to move all the boxes of copier paper that were piled behind the rack not to stack things on the rack. The fan blows like a hurricane.
 

macsound

Well-Known Member
A dying DC power supply for the wall stations would explain the steady flashing symptom you get with the houselights. Effectively the PSU trying to power up and then failing, but getting enough juice to the card and panel for it to send out a signal.
 

Butch!

Member
Well with Holiday shows and the Holidays this sat on the back burner, but now that the school is open again I spent a few more hours trying to figure this out. There is only one power supply in the rack and it appears to power everything. It is supposed to supply +5 v, +12 v and -12 v and meters out at +5.01 v, +11.68 and -11.72. There is a trim pot for the 5 volt, but none for the 12's. These voltages are steady and don't change when DMX is present so unfortunately the theory that the flickering is caused by a power drop didn't pan out.

I found a 24 VDC relay hidden in the jumble of wiring that comes in from all of the wall stations. Based on the wiring tracing that's been done so far it appears that when it is energized it cuts power to the wall slider stations in the booth and on the stage. As it is 24 volt it has to be using the +12 v and the -12 v wires, but the -12 v wire hasn't shown up anywhere in the wiring so far. There is a round connector in the booth and another on stage that appear to have been for some kind of TTI console and perhaps the - 12 v wire shows up in that connection. So it may be that the purpose of the relay is to lockout the wall sliders when that board is plugged in, but I'll have to trace out that section of the wiring. The relay didn't look good and it turns out the contacts were fried. I was able to clean them up enough to get current to flow through it but it didn't make a difference. The coil checks out with a meter but I have a new relay on order.

There was another head scratcher with the wiring tracing. While the power supply puts out +12 v, the wall stations are all getting +10 v. There aren't any voltage regulators anywhere else in the system so it makes me wonder what's going on, maybe there is another power supply hidden in a raceway.

I have a call out to Litetrol but they're all out of town this week on a job.

I've attached pictures of 3 of the control cards just in case someone will recognize them. They're all TTI (Theatre Techniques Inc). One must be the phase monitoring card, the one with the red LEDs is the main processor and I'm not sure about the last one. It's some kind of conrtrol card, but there are two more cards that are clearly the firing cards, granted they're in the slots for dimmers 97 to 144 and 145 to 192.
Dimatronics Phase monitoring card.JPG
Dimatronics control card.JPG
Dimatronics ramp card A.JPG
 

FMEng

Well-Known Member
Fight Leukemia
This is just a guess, but I think the middle card, with the sticker that says "set for RS-422," could be related to the house light stations. RS-422 is a serial communication protocol for twisted pair that would be a likely way to get control from the stations. It's clearly got a small microprocessor.
 

Butch!

Member
@FMEng Thank you for the reply. The houselight system is totally analog. Something as simple as a door station with an on and off button has 6 wires going to it - a hot, a cold, a wire for the on button, a wire for the on LED, a wire for the off button and a wire for the off LED. The stations with the pushbuttons for the 8 presets (plus off) are just as bad with 20 wires going to them, plus 6 wires for on/dim/off and three more wires for the sliders. In the rack it's a giant mess of black spaghetti where all these wire converge on a few terminal strips.

In the booth and backstage there are panels with a 5 pin DMX port, some kind of oddball round multipin connector (believed to be for some kind of TTI console) and a jack that looks like a computer monitor port, but with fewer pins (a DB9 I think). The cables from both of those ports get spliced together in the rack and the resulting cable pugs into the port on that card just above the round yellow sticker. I believe this is/was a way to interface a computer to the system and update the programming. At any rate I unplugged the cable and it had no effect.
 

mhuntoon

Member
I'm assuming there's DMX conversion (up or down) happening somewhere as you mentioned ETC Express is the console. I would imagine getting a tech out or sending the cards out for repair would be more expensive than replacing the station with a cost effective DMX snapshot station. Both Doug Fleenor and Pathway have low cost solutions. I run into these installs often and understand the system replacement cost hurdle. Bottom line- this dimmer & HL system reached end-of-service a few years ago.
 

Butch!

Member
@mhuntoon I suggested that they consider replacing the misbehaving architectural system with a DMX snapshot system. I was aware of DFD's system, but haven't heard of Pathway thanks for mentioning them. There are multiple panic stations that would have to be worked into a replacement system and that's causing a problem as the existing system is totally analog with a collection of individual 18 gauge wires running to every station (6 wires for a panic station, 29 wires for a preset station with 3 sliders). Just about all the DMX snapshot systems require DMX, cat 5, etc and running all new cable pushes the cost out of reach. The Lightronics SR516 is capable of supporting 3 pushbuttons using analog wiring 1 (hot and 3 switched returns) so if they go for a replacement they will go that route as all they need is panic/off functionality at the remote stations.
I'm in a strange place with this whole thing as I don't work for this District, the IT person for the school called me for advice. Yes, in rural Pennsylvania dimming systems are the responsibility of a school's IT department. The rigging is also their responsibility as the movie screen is attached to it.
 

Butch!

Member
FIXED !!!!! As @BillConnerFASTC wrote earlier in this thread - 'I think this needs a good technician.' and they found one!

The School's IT person, who is somehow responsible for 'auditorium technology' never told the District's IT chief about the problem until last Thursday. The District's IT chief put out a mass e-mail to all the IT chiefs he knew at other area School Districts and one of them suggested a small 'lighting and a little bit of sound' company around an hour away.

They sent a tech out the next day (a Friday) and, from what I'm told, the guy scratched his head, said 'That's not normal' and then pulled out a meter and started taking readings all over the place. He said it was definitely a voltage issue and had pinned it down to one wire which was too low. He then tore into the rack to track down the problem. In the process he found a bad relay that looked like it had rusted or burned inside. The coil looked scorched and the contacts were all trashed and wouldn't pass current. He said it wasn't the problem but that it was a sign of low voltage - the coil wasn't getting enough power to operate and the coil heated up and cooked everything inside. Only problem was that the relay was fed from a different wire than the one he was tracking which meant that there were now two bad voltages. Eventually, just as @FMEng thought, the tech found a doorbell transformer tucked up in a corner of the rack. The transformer fed two PCB cards with components on them which the tech said were changing the AC to DC and regulating the voltage. The transformer was putting out what it was supposed to but one of the cards was putting out the wrong voltages and fed both of the wires with low voltages. He knew what all the little components on the card were and ran a calculation based on the markings and determined that the configuration was supposed to be putting out 10 volts on one wire and 20 volts on the other - it was putting out 4.8 and 10. He said that the card needed to be worked on but that he didn't have the components with him or in stock, but he would get them ordered and shipped in over the weekend and be back Monday morning. He came back Monday morning, pulled the card out, did some soldering and 1/2 an hour later the system was working perfectly.

They tell me the tech spent around 3 hours on site between the two trips and that it wasn't very expensive.
 

FMEng

Well-Known Member
Fight Leukemia
Based on my 30 years of doing electronic maintenance, the leading causes of trouble are:

(in no particular order)
1. Dirty switch and connector contacts
2. DC power supplies
3. Baked electrolytic capactors (primary cause of #2)
4. Batteries (memory and UPS)
5. Fans (often contributes to #2 and #3)
6. Hard drive failure
7. Loose terminals
8. Microprocessor needs a reboot

Heat is the enemy. Electronic equipment that runs warm, from poor design, poor installation, or a bad environment is doomed to premature failure.
 

Jay Ashworth

Well-Known Member
> and, from what I'm told, the guy scratched his head, said 'That's not normal'

Generally, we say "Well, that's odd...".

:)

Glad you got it fixed.
 

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