8mm Forum: Bulb keeps blowing

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Topic: Bulb keeps blowing

Rick Schleicher
Junior
Posts: 6
From: San Diego, CA, USA
Registered: Oct 2016

posted October 31, 2016 12:02 AM

Hello,

New to this forum [Smile]

I have our family Regal K-109 projector and movie camera along with 30 movies. My issue is the projector keeps blowing the bulb. Old bulb blew in about 1 sec. Bought 2 more and the second bulb blew in about 5 seconds. Not ready to install the second bulb until I find the problem.

At $15.00 each, I need a solution

Thoughts?
Rick

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted October 31, 2016 02:20 AM

Welcome Rick. I can think of a few reasons a bulb will blow. The K109 takes a 120V 750W bulb...You should measure the voltage of the house outlet to check for spikes. Then check for bad wiring in the lamp holder. The wiring is very old on these machines. The power switch could also be faulty. Make sure the bulb is well seated in the holder. It is always possible that the second bulb was also bad. This happened to me recently. I thought it was the projector causing the lamp to burn out... and I too was afraid to put in another bulb. However the next bulb worked fine. If you don't find anything electrically suspicious you will have to try the third bulb.

--------------------
Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted October 31, 2016 04:09 PM

Most of the time we see something like this, it's because somebody is driving the bulb with way too much voltage, but with a 120V bulb, how can that be?

Let's say you had a projector with a 120V bulb set up for North America, and you plug it in in Europe. Your 120V is now maybe 250 and of course you've created a very expensive photo flash!

Let's say you do the same in reverse: you plug your European projector in in San Diego and your 120V has now become less than 60! You'd be lucky to get any light at all! (It would certainly last a long time...)

I'm with Janice here, you need that voltage measurement.

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All I ask is a wide screen and a projector to light her by...

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted October 31, 2016 06:19 PM

Beyond that, poor contacts in heavy current lamp circuits is all too often the main offender in my experiences.
Even at this voltage this is still a 6 & 1/4 amp circuit (approx).
750w is a serious amount of wattage for a projector lamp and these are old machines, often with very old joints, insulating blocks and wiring.

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"C'mon Baggy..Get with the beat"

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Rick Schleicher
Junior
Posts: 6
From: San Diego, CA, USA
Registered: Oct 2016

posted October 31, 2016 09:04 PM

Well, the outlet reads 118.8-119.2. Initially it was 119.1 and slowly went up and down as noted over 30 seconds, never spiked or went above 119.2

As for seating the bulb, I was able to insert and give about 1/8th twist or maybe a bit more, how much more should it go? Will it go to a stop?

I'll start looking at wiring this weekend

Since I am not electrically inclined, do you have recommendations for someone to service it if need be?

Thanks in advance
Rick

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Mathew James
Jedi Master Film Handler

Posts: 740
From: Hamilton, Ontario, Canada
Registered: Dec 2014

posted October 31, 2016 09:04 PM

750W? Gulp...
There goes the hydro bill [Smile]

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--
Cheers,
Matt 📽

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Maurice Leakey
Film God

Posts: 5895
From: Bristol. United Kingdom
Registered: Oct 2007

posted November 01, 2016 03:30 AM

Rick
The DDB lamp has a medium pre-focus base and should be turned 90 degrees clockwise after inserting in the lamp holder.
The two fins are differently shaped which only allows insertion the correct way.

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Maurice

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted November 01, 2016 12:30 PM

The original bulb that came with the Keystone K-109 projector was a 15V max bulb. This obviously would blow rapidly if connected to a 118 - 120v outlet. The correct bulb should be a DDB 750W 120V - 125v 25 hr.

JUST A THOUGHT...

You might try using a variable voltage regulator to lower the AC voltage a bit going to the projector. To see if that helps.

Here are two I use...the one on the left I purchased off Ebay and the one on the right I made using a common dimmer switch.

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Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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Rick Schleicher
Junior
Posts: 6
From: San Diego, CA, USA
Registered: Oct 2016

posted November 03, 2016 08:52 PM

Well good news

I couldn't see anything wrong with the wiring. Cleaned all the lenses, film gate... and installed a new bulb, this time I made sure it was fully seated 1/4 turn to the stop, unlike the last time I only went 1/8 turn cuz I couldn't tell if that was it or not.

And.... everything works great, even watched a Popeye cartoon

All's well in this 8mm land

Thanks everyone
Rick

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Janice Glesser
Film Goddess

Posts: 3468
From: Sunnyvale, CA USA
Registered: Sep 2011

posted November 03, 2016 09:59 PM

Nice work Rick. Sounds like you are in business. There's also a good chance the second bulb was defective.

Enjoy your films!

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Janice

"I'm having a very good day!"
Richard Dreyfuss - Let It Ride (1989).

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