Automated Fixtures Best guess as to why my fixture is overheating.

[StevieP]

I have some Geni (Irradiant) OBY-600 wash fixtures. I have rehabbed them with new control boards and while using them in a show last weekend one of them blew the Thermistor used to limit the current inrush. I replaced the Thermistor with a part from a spare fixture, but it is running extremely hot and the wires connecting to the thermistor are almost too hot to touch. Also I turned the fixture on in the shop and set it to a repeating cuelist. After about 3 hours the lamp would shut off, however the motors were all still functioning. after the proper cool-down (fixture still on and running) the lamp would come back on and it would continue to operate normally. This process repeated. The Lamps in these fixtures are the one that were in them since I bought them, however since I changed the pc boards the timers are no help.

Does this sound more like a ballast, thermistor or lamp issue?

Thanks for any ideas you can give me,

Steve

 

[TimMiller]

If the fixture is getting physically too hot the. It is a cooling issue but if the lamp wires are getting way hot then their is most likely a termination issue. Any idea how old the lamp is? Lamps start to pull more current as they get older. If this does not fix the problem I would try replacing the lamp socket. It could also be
The ballast is not putting out the voltage needed and the amperage is going up, but then that raises the question does the unit have to struggle to strike the lamp or does it fire up right away?

 

[StevieP]

I will check the voltage coming out of the ballast. I know the bulb has been in use since I've owned this fixture. Tim, thanks for your help.

 

[church]

If the fixture is getting physically too hot the. It is a cooling issue but if the lamp wires are getting way hot then their is most likely a termination issue. Any idea how old the lamp is? Lamps start to pull more current as they get older. If this does not fix the problem I would try replacing the lamp socket. It could also be
The ballast is not putting out the voltage needed and the amperage is going up, but then that raises the question does the unit have to struggle to strike the lamp or does it fire up right away?

The device your are refering to is a varistor (voltage dependant resistor) not a thermistor a thermistor is a temperature sensing device created by a junction of two dissimailar metals). It's purpose is to limit or clamp voltage transients when. If it is getting hot it suggests it is seeing a sustained high voltage condition consequently you are seeing excessive dissipation in the device. Have you checked the voltage as suggested by a previous poster?

Before you check the voltage do you know what the voltage should be? do you have the test equipment to safely test the voltage and do you have the trainin ? Sorry if this seems to be patronising but many people read this site and this is a dangerous test and must be performed accordingly.

 

[ship]

What does the lamp look like? Take a photo and from Mark to I or many people can start to analize the problem by way of that due to experience. Would also help to say if just plain lamp to old. This assuming you didn't change the lamp.

Lamp pins are an indication of condition of lamp socket. If the pins on a lamp are overheated it also indicates a bad socket it was plugged into. Terminal screw tension or bad crimps can also be the cause in trashing such things and causing failure - this as with putting a perfectly good lamp into a bad socket if the case. Or the reverse of it - exchanging lamps between fixtures short of inspection is always a bad even if quick solution for now. Voids any sense or warranty unless you can completely track lamp hours etc. necessary, and should you put a bad lamp from bad base with into a fixture with good base but other issues - you just spread the bad base virous to another fixture in compounding the problem due to now continuity issues added on.

You can after inspection at times re-use lamps in another fixture if not bad otherwise and even if they had power supply issues, but not in the same fixture and only after inspection as to cause and condition. I call this ballast signature. A lamp only somewhat destroyed say in an old Mac 2KE might work just fine in a new VL-3K SP. Halogen effect... Every ballast goes bad and all have a different power signature in how a lamp in a bad one might react in another. Good to if not bad lamp to re-task, but bad short of real inspection with notes per that lamp's serial number that would fit warranty rules for return the lamp just lamp swap between fixtures.

How does a lamp company remove ability to return tracked lamps? Remove the serial number... How does the customer continue serial numbers - if porcelain base to it, graphite pencil and your own tracked serial number for the lamp.

Not mentioned but frequently a cause: are your cooling fans working correctly? Fixture cannot know if the fans are working correctly and frequently - possibly more frequently than a ballast or other cause a fan is to be looked at.

Finally atmosphere. Recently had a bunch of fixtures in from another company that were having overheating problems. Gee, when is the last time you cleaned them? Filters were totally clogged up with fog goo and dust in the cause.

 

[StevieP]

Thanks Church,

The part I was referring to is an SCK20120 (data sheet found here) But I am not an engineer so I could be wrong. I have a decent meter and I have a fixture that is working perfectly so I did check the voltage they were both within a volt of each other and consistant with supply voltage.

I pulled the bulb and it was "cloudy" to a point I couldn't see through it. I put a new bulb in and it has been running for about 6 hours with no problem. I was told by a more experienced guy than me that a cloudy condition indicated the bulb was nearing its life expectancy. so all of that makes sense.

I am ready to call this good and I thank you both for helping with this, every day is a learning experience.

Sincerely

Steve

 

[StevieP]

Ship- all great points. I acquired most of my fixtures from clubs and churches that stuck them in a ceiling and turned them on for years on end. I rehabbed and cleaned them, so you will never have to tell me about the importance of fans and filters! lol

I was not aware of the terminal screw tension. I tend to wrench down pretty tight. Can you share the best way to tighten them?

See below looks like it was a bulb getting ready to go...

 

[ship]

No photo if intent but seemingly all good. Look to the pins of the bad lamp - will also tell a lot for at least warnings about heat and the socket/wiring etc. Most brands unless "gold" should be shiny brightwork no matter the age of the lamp. Call the cloudy ones also in weather terms "Snowball" or say snowball or even crusty snowball dependant on heat with a coaxial frost window at also times with a lamp in certain types - that coaxial frost window on the globe of the lamp on the opposite side of the fill pinch.

My infamous lamp globe description termonogy used with most vendors to describe a lamp globe condition from vapor clouds to silver mist available upon request in how to describe a lamp globe or cause of failure or it's condition. Even coded them for shorthand at one point. 13 years of inspecting bad mover lamps under a magnifying glass, reading manuals on them... got fairly good in figuring out the cause of failure. Not that it often does any good. Either on tour or within a day of returning, onto another tour verses days or months for me to inspect all the lamp - including them changed by "Ronald McDonald" because it's "Bad." Often months between I detect as a problem by way of the lamp going bad and the fixture stop working completely say with a bad lamp socket - often in 100 hour increments before this perfectly good lamp in a bad socket stopps working. "Broken" I term as outer pinch failure due to bad lamp socket way too much. If only those on sit could spend a moment or two in theorizing about what caused the lamp to fail... would save thousands of dollars per year in putting perfectly good lamps into bad sockets or bad fixtures. Literally I count down the lamp life hours at times with hundreds of fixtures until, gee we should probably replace the socket... Bad base yes, fan not working on the fixture as motivator possible also.

Heat issues are normally shown in heat damage. Voltage issues by way of power supply or ballast or transformer are normally tungsten (silver) in the globe shown. Yes you might see tungsten in the globe with a bad lamp socket due to voltage limiting nature, but you would also see the heat damage to the base. Sort of simple simplification amongst lots of lamp / fixture problems but very accurate to look for. Bad fans can be shown as the above or more. (Lots more details obviously.)

Osram has a lot of good PDF files to read and study on these subjects. Look up your lamp and read the PDF files attached in further readings - very well written and educational. This for all types of lamp.

On screw tension, I don't work on movers - just inspect and buy the lamps but would suspect tight isn't lilly lizard and such tension by crew chief should be checked for new people at times. Factory spec or tight best I could say other than if a screw tightening onto a stranded wire ask if it needs a ferrule?

 

[StevieP]

By the way, just heard back from Thinking electronics (the original maker of the part that fryed) they don't make that particular part (sck 0120) anymore but gave me some replacement parts. I thought I would post the email, just in case anyone out there had a similar problem.

From Thinking:

Hi Steve,

Thank you for the inquiry!

We think it may be one of our old items that is already EOL. The spec. should be 1Ω, 20A.
For replacement, we would recommend our existing P/N SCK251R0MSBH-P (Spec.: 25mm in diameter, 1Ω, 20A)
or SCK201R0MSBY-P (20mm in diameter, 1Ω, 13A)

Is there any further information you may need?

Thank you and Best regards,
Penny


Thinking Electronic Industrial Co., Ltd.
Penny Huang

 

[StevieP]

Okay, Sorry its been a while, but I am still battling my oby-600. So here is what happened since we last talked. I have taken a good light and set it next to the "bad" light, removed all the covers. I thought if it was overheating I might see a change. I did not. Let me describe the path the lamp circuit rides.

AC in (120V) ----> switch,fuse------> Thermistor ------> very large capacitor----> EMI filter-----> transformer ----> MAIN PCB (input to solid-state relay to output)------->Balast------> heat sensor1 -----> heat sensor 2 -------> Ignitor (red wire- see below)

from the ignitor: white wire ------> left side of bulb
Blue wire---------> right side of bulb AND back to the large capacitor from above
Red Wire --------> see above

Problem: Lamp strikes and operates normally and is fully functionable for 1 to 2 hours. The lamp suddenly shuts off (no noises) and cools down. once shut down, it cools and restrikes. All other functions operate normally. All fans are running and fixtures are clean


Tests so far.


Voltage:
line in: 119V
thermisor in: 118V
Thermistor out 118V
Balast in :109V
Ballast out 233V lamp struck, 227V Lamp off
Voltage matched to balast on both heat sensors and ingitor


Swapped parts with good fixture with no change:
Thermisor
Ignitor
Bulb
Heat Sensors
balast
Main PCB

I have tested the relay on the main PCB and it measured 238 or so when I turned the lamp "OFF" with button controls on the front i hear the relay click and the Voltage drops but only 10 V or so. Thought that was strange.

I am thinking of swapping the big capacitor because its all that is left, but don't like playing with big capacitors. The bulb is the easy answer but I don't understand why the problem doesn't follow the bulb to another fixture.

The bult is a double ended 575. Blades and clamps look great.

Anybody got any other good ideas?

 

[JD]

Okay, Sorry its been a while, but I am still battling my oby-600. So here is what happened since we last talked. I have taken a good light and set it next to the "bad" light, removed all the covers. I thought if it was overheating I might see a change. I did not. Let me describe the path the lamp circuit rides.

AC in (120V) ----> switch,fuse------> Thermistor ------> very large capacitor----> EMI filter-----> transformer ----> MAIN PCB (input to solid-state relay to output)------->Balast------> heat sensor1 -----> heat sensor 2 -------> Ignitor (red wire- see below)

from the ignitor: white wire ------> left side of bulb
Blue wire---------> right side of bulb AND back to the large capacitor from above
Red Wire --------> see above

Problem: Lamp strikes and operates normally and is fully functionable for 1 to 2 hours. The lamp suddenly shuts off (no noises) and cools down. once shut down, it cools and restrikes. All other functions operate normally. All fans are running and fixtures are clean


Tests so far.


Voltage:
line in: 119V
thermisor in: 118V
Thermistor out 118V
Balast in :109V
Ballast out 233V lamp struck, 227V Lamp off
Voltage matched to balast on both heat sensors and ingitor


Swapped parts with good fixture with no change:
Thermisor
Ignitor
Bulb
Heat Sensors
balast
Main PCB

I have tested the relay on the main PCB and it measured 238 or so when I turned the lamp "OFF" with button controls on the front i hear the relay click and the Voltage drops but only 10 V or so. Thought that was strange.

I am thinking of swapping the big capacitor because its all that is left, but don't like playing with big capacitors. The bulb is the easy answer but I don't understand why the problem doesn't follow the bulb to another fixture.

The bult is a double ended 575. Blades and clamps look great.

Anybody got any other good ideas?

Did you check for airflow issues? Could be the temp sensor is detecting a valid problem. Regarding the prior conversation on the Thermistor, getting real hot is what they do! The heat causes them to drop in resistance and they have to stay hot in order to stay low. Often, they unsolder themselves or self destruct.

 

[Peter Kolbe]

To the OP,
I know this is a very old thread. But I am trying to fix an OBY-600 for my church.
It had a problem where it started jittering the motors, and not listening to commands, and the demo mode was not working.
Unfortunately I had a scope probe slip when I was trying to locate the problem, and I managed to fry the 2 PIC microcontrollers on the control board (the board with the switches and LED display).
Those 2 Microcontrollers get so hot they are untouchable almost immediately.

With those microcontrollers out of the circuit, the initilization works fine, the motors home, etc.
Which means that the rest of the fitting is fine.

I was told by a repair company that these are discontinued, and that no parts are available for it.
Does anybody have a control board (or even just those 2 microcontrollers) that they will be willing to part with. I will gladly pay postage to South Africa.

Thank you
Peter Kolbe
Rhema South Coast Family Church