I replaced some bulbs in a client's sign and it still won't light. the photocell is fine because I tested it and the reader board underneath it lights just fine.
I tested the voltage at a couple of the contacts before installing the bulbs and got about 14v.
If it's a bad ballast or transformer would you get any voltage at all?
Posted by Roy Frisby (Member # 736) on :
Yep, there is a low voltage across the filaments in the lamps, but there should also be a high voltage there also. Something on the order of 750 volts. Chances are the ballast is bad...any tar cooked out on the ballast? The 14volts appears across the two leads on the end of the lamp but the high voltage appears across the length of the lamp (end to end). BE CAREFUL!
[ July 18, 2003, 09:06 PM: Message edited by: Roy Frisby ]
Posted by Wayne Webb (Member # 1124) on :
Thanks Roy, I didn't even look at the ballast. Just figured the bulbs would be the solution. I will do that. If the tar isn't oozing out, how do you test it? Are the lamps connected in a series or parallel circuit? thanks again
Posted by Richard Bustamante (Member # 370) on :
There is a wiring diagram on the ballast. All the leads are color coated. The light tubes show it's wear by a slight discoloration on the ends. Most of these lit signs have a timer which turn it on and off. Be sure to disable the timer. You don't want it to turn on while your working on it. Take plenty of wire nuts. -Rich
Posted by dveenema (Member # 833) on :
Better yet you could leave this job for those who do it for a living. As well most places require sign servicemen to be certified. I build, install and service electric and neon signs every day. I don't carve wood! I don't hand paint! I stick to what I know.
Posted by Jeff Ogden (Member # 3184) on :
Wayne...
I can send you a wiring diagram if you tell me how long the lamps are and how many are on the ballast. Sometimes the diagram has been painted over, or just yellowed from heat to where you can't read it.
In answer to your question, what you want to do is check for a reading at all the sockets. I usually check that at the ballast first. If you have voltage in all the circuits, and the sign still does not light, then you can check at the socket. Sometomes they go bad, but if there is no reading at the socket, it could be a short on the raceway leading to the socket. Do a quick visual to see if there are signs of water build-up after a rain...there should be drain holes along the bottom, where some of the raceways are. Most shorts happen there. Be sure to turn the power off when at this stage of the job.
A quick thing alot of service guys do is feel the lamps. sometimes you can feel a vibration in the lamps that have good circuits, and none in the bad circuit. So the bad one could be a ballast, but could also be a socket or short.That narrows down the search....
Posted by Roy Frisby (Member # 736) on :
But Dennis,
quote:Better yet you could leave this job for those who do it for a living. As well most places require sign servicemen to be certified. I build, install and service electric and neon signs every day. I don't carve wood! I don't hand paint! I stick to what I know
Did you know everything the first time out? I don't think so...everyone has to learn! Give Wayne a chance.
Posted by Wayne Webb (Member # 1124) on :
Yeah, I wasn't wild about taking it on in the first place and I do in fact specialize in wood, HDU etc. But the electric sign man left town several months back and my long time customer asked me to take a look at it after I replaced the faces. I've wired my own house and shop all the way from the weatherhead, ground rod, meterbase, breaker panel all the way to the last receptacle and helped wire a few more so it's not that foreign to me. Im also cautious and respect it enough not to work on live circuits. A poor redneck signman sometimes has to be a jack of all trades. But I don't know much about ballasts though.
Jeff, the 4 lamps are 9' long and I would appreciate the diagram. My fax is 850.638.8580 or you could email it. Thanks. I'll do that visual and check that ballast and circuits next week.
Posted by Curtis hammond (Member # 2170) on :
ballasts are around $60 bux. bigger signs have bigger ballasts which cozt more..
Posted by Wayne Webb (Member # 1124) on :
Well, I had looked at the sign after dark and it wasn't lighted. Maybe it was just the breaker. The client just called, wanted to know when I was going to send the bill!! I'm still getting over the shock.
Says it's lighting fine.
[ July 21, 2003, 11:01 AM: Message edited by: Wayne Webb ]
Posted by Brad Ferguson (Member # 33) on :
Like Roy said, you should get somewhere close to 800 volts accross the sockets at opposite ends of a lamp. That means a reading from socket to ground, the cabinet, should be about half that. Disclaimer: I am not an electrician. For what it's worth: Running a sheet metal screw through a sign cabinet into a ballast will ruin the ballast. I know this.
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