8mm Forum: Sankyo 702 light died

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Topic: Sankyo 702 light died

Peter van Zand
Film Handler

Posts: 95
From: Amsterdam, Netherlands
Registered: Apr 2009

posted January 20, 2010 10:34 AM

Yesterday when I was projecting some new shorts the lamp of my 702 suddenly quit. No problem, I thought, replace the lamp and on with the show. But it seems to be a power issue, no current is reaching the lamp. I checked the fuse and it's allright. Can someone maybe shed a light on this? The Sankyo was my favorite projector.. [Confused]

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www.vergetenfilm.nl

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Steve Klare
Film Guy

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

posted January 20, 2010 02:56 PM

Peter, how comfortable are you poking around circuits looking for voltages? (Especially when there is line level voltage present on the transformer and possibly the motor too?!)

This should be a pretty simple circuit: I bet we can find out where the problem is.

PS: What bulb does this machine use?

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

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Peter van Zand
Film Handler

Posts: 95
From: Amsterdam, Netherlands
Registered: Apr 2009

posted January 20, 2010 03:24 PM

Steve, I have a voltage meter but I wouldn't know where to measure. It's all packed tight inside and not very accessible, but I'm prepared to experiment and learn. Thanks for any suggestions.
It uses a EFR 15V 150W bulb

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www.vergetenfilm.nl

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Mike Peckham
Phenomenal Film Handler

Posts: 1461
From: West Sussex, UK.
Registered: Jun 2003

posted January 20, 2010 04:00 PM

I had a similar problem on my Sankyo 800, turned out to be the lamp holder. I would suggest you trace the lamp holder wiring back to the transformer and with the motor running and the lamp on, test the voltage at that end.

If you get 15v you'll know that it's the lamp holder that's at fault, if you don't you'll need to look further...

Hope that helps.

Mike

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Auntie Em must have stopped wondering where I am by now...

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 977
From: Ortona, Italy
Registered: Jan 2004

posted January 20, 2010 04:38 PM

Actually the lamp holder tends to gather dirt/oxide on the very contacts which touch the lamp's pins. When this happens it's not rare to have the lamp working again in pre-heat mode by gently moving the holder back and forth. This usually fix the problem (temporarily). For more consistent results, you need to clean the inside contacts of the lamp holder and possibly the lamp pins too: for the latter ones, I use extra fine sand paper; for the former I simply spray some contact clening fluid inside the lamp holder, and put the lamp pins in and out a few times after some minutes. Of course it is also possible to replace the whole holder. In any case I think this problem should not be underestimated as poor contact between the lamp socket and the pns might lead to over heating of the socket itself due to arching (in the worst circumstances).

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Maurizio

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Graham Ritchie
Film God

Posts: 4001
From: New Zealand
Registered: Feb 2006

posted January 20, 2010 04:46 PM

Peter
Just a thought, although I am not familiar with your projector I would remove your new lamp again and give the two lamp pins a really good clean with some fine wet/dry rubbing down paper. In most cases that should do the trick, in fact every time I change a lamp I clean those contact pins, if you dont have good contact you get resistance and that in turn creates heat which will in time cause the lamp holder to fail.

Graham.

Sorry Maurizio I was away from the computor so I didn't see your reply I think we were both saying almost the same thing. [Smile]

I would add a word of caution to Peter that some spray CRC contact cleaners are flammable so be carefull using those things [Smile]

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Steve Klare
Film Guy

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

posted January 20, 2010 08:19 PM

Peter,

Use the AC voltage ranges on your meter and for heaven's sake be careful!

If you can get to the point where the wiring enters the socket and touch the bare wires at that point, you can test the socket. Otherwise try to get the the other end of the socket wiring and measure what the voltage is doing there.

If you can find the switch that controls the lamp, the voltage across it should be zero when the switch is turned "on", and 15V when the switch is turned "off".

If all of these readings are zero, trace out the lamp wiring to where it is wired to the transformer and see if there is 15V present going in.

Something, somewhere is open circuit and getting all the voltage that should be on that bulb.

Is there one fuse for the whole machine or does the lamp circuit have its own?

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

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Maurizio Di Cintio
Jedi Master Film Handler

Posts: 977
From: Ortona, Italy
Registered: Jan 2004

posted January 21, 2010 10:54 AM

Hi Graham. It's good to punctualize some sprays are flammable. I didn't, just because I usually wait until it is fully evaporated before operating the projector again so I assumed everybody would do the same [Frown]

Thank you

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Maurizio

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Peter van Zand
Film Handler

Posts: 95
From: Amsterdam, Netherlands
Registered: Apr 2009

posted January 22, 2010 01:57 PM

Thank you all for your input, I am happy to say that I fixed the problem. It was indeed the lamp holder which caused the failure. I picked up a new one and some advise on how to go about it at Parallaxe today (see my post about that visit here: visit to Parallaxe and after replacing the socket all was dandy again [Smile]

It's great to have so many people chiming in to try to fix problems that other forum members encounter.

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www.vergetenfilm.nl

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