Marc-300 problem?

[Steven Singarella]

Hello I want to know how to test to see if I have power going to the Marc-300 socket pin-holes on my Kalart/Victor 16mm Projector? I have just about all the meters but dont know how to do it? The Projector works fine, sound, film transport, etc. I had three bulbs in stock but none will strike! It was just running fine and now im in the dark. I purchase 2 NOS bulbs on ebay and they are all not working. When I put the ohm meter on the new bulbs they read nothing? So im trying to see if there is power coming out my projector light sockets Pins? My Marc-300 kalart/victor has the Power pack under the Projector not inside. What should I do to figure out what it is....lack of good bulbs or bad Projector?

Steve Singarella

I put a photo below of the Projector bulb Pin-holes...

[Lindsay Morris]

DO NOT try and measure voltage on the lamp pins as you will most likely blow up your meter. The only way you can check for the DC voltage is to disable the ignition pulse circuit and switch the machine to Lamp ON.

The reason is that the Marc 300 lamps are mercury discharge lamps and need a high voltage pulse (10Kv or more) to ignite the lamp capsule and then the DC voltage from the power supply maintains the arc and you have light. On the 666 the DC voltage is around 36V

The lamps you bought my well have been OK as they DO NOT register on the Ohm meter so it sounds to me that there is NO Ignition pulse happening and without that there will be NO lamp going.
Not familiar with Kalart Victor Marc 300 machines but on the Bell & Howell 666 there is a clicking sound as the lamp is started which is a small relay inside the power supply generating the ignition pulse.
The later model Bell & Howells used the slight smaller lamp (the Gemini lamp series) and were fully solid state and those machines were buggers to work on as the circuitry was quite complex as compared to the 666 machines.
I have kept a couple of dud Marc 300 lamps that will only flash and use those to test for the ignition pulse and from what you say None of the lamps you have there will strike.

BUT DO they flash briefly?? If they do then the ignition pulse is there but NO DC there to sustain the arc discharge.

To go much further you really need a circuit of the Kalart.
Lindsay

[Steven Singarella]

Lindsay, Thanks for your fast reply! My Kaylart Victor is the series 80-25 solid state unit with the power supply that is independent and sits under the projector. From what I remember the bulbs used to stike a hum and little flash soon as I pushed the light switch. That was 3 days ago.... now when I try to start the bulb... NOTHING. I used to be able to feel it, so to speak. I do have another power supply for my other Kalart Victor 70- series that is doing the same thing....no strike. I even tried switching them and same, no flash or strike. From what I understand you are telling me if I had a brand new power supply it should work? Or are you saying that the problem (the bad relay) my be inside the projector itself? The Kalart Victor uses the marc-300 EZM bulb 37.5 volts. Its strange the I tried the spare Kalart and got the same results. The Kalart I use all the time is brand New old stock I bought without any miles whatsoever! The power supply has 2 fuses both 250v 15amp and I replased them both. Could the projectors switch be bad? The switch is old school clicker type that you cant mistake what position its in and make a snappy "click". This all started a few days ago when I was hooking a subwoofer 4 ohm in parallel with another 8 ohm speaker. Sound is still fine and amp in the projector fine. Could I have damaged the unit power supply this way, I think not?

Thanks Steve