Hanimex Projector Problems

Post by **merman** » Tue Apr 11, 2006 11:41 pm

I was recently given a Hanimex SR 8600 projector which projected beautifully for a few days (apart from a tendency to chew film while loading). I got it out a couple of days ago however, and it blew the bulb as soon as I turned it on. I ordered two replacement bulbs and tried one of those, which didn't seem to work, so I opened it up to check power to the bulb which is fine. I then put the second new bulb in only to see that blow as soon as it was turned on - so I guess that must have happened with the first replacement too, but I missed it.

I'm hoping someone has some idea as to what might have gone wrong on this - it would be great to get it working again, and I can't afford to blow any more bulbs! I've a small stack of newly processed reels I'm currently unable to watch, and semi-decent projectors don't seem to come cheap from eBay.

Bulbs blow instantly - they're 8V 50W bulbs and the power supply is giving out 8V, so I don't really understand why they're blowing. The motor seems to run normally. Any advice gratefully received...

Cheers - Tom

Post by **Janne** » Tue Apr 11, 2006 11:53 pm

merman wrote:the power supply is giving out 8V, so I don't really understand why they're blowing.

Did you measure AC or DC?

Post by **merman** » Wed Apr 12, 2006 12:00 am

Janne wrote:Did you measure AC or DC?

8V DC off the transformer where the wires come off to go to the lamp/switch. That's as it should be, yar? It's actually 8.1 V DC but that seems reasonable to me.

Post by **VideoFred** » Wed Apr 12, 2006 7:47 am

A transformer, connected to the 220V AC power supply, always gives AC output.... Unless there's a rectifier connected at the output.

Your bulb is getting to much Voltage, no doubt.
You must measure again, in AC range.
The transformer could be broken...
There could be some wires making unwanted connection, too.
Check all the on/off switches.

Fred.

Post by **jpolzfuss** » Wed Apr 12, 2006 9:19 am

Hi,

most sound projectors are using 12V 100W lamps. (There are a few with 12V 80W, 12V 150W or 15V 100W though.)
Only 50W is very odd, so is 8V.
When measuring: Keep in mind that many projectors switch voltage from "power save" to "full power" when the film is running. And some projectors even do have two or more brightness-steps (=two or more voltage steps).

JÃƒÂ¶rg

P.S.: This shop lists your projector as "uses 8V 50W", too:
http://www.donsbulbs.com/cgi-bin/r/b.pl ... ~ansi.html
Nevertheless the ST 8600 is using another lamp:
http://www.donsbulbs.com/cgi-bin/r/b.pl ... ~ansi.html

Post by **Sparky** » Wed Apr 12, 2006 9:24 am

The voltage of an unloaded transformer will be considerably higher than its rated voltage though so don't be shocked (;-) ) if it reads 12V AC or more- have you got the mains voltage selector set right?
Mark

Post by **Angus** » Wed Apr 12, 2006 12:59 pm

Some of the smaller Eumigs used 8V 50W bulbs, it is not all that unusual.

Did you keep the original bulb to check the its reference number?

Post by **merman** » Thu Apr 13, 2006 1:41 am

Hi

Thanks for all the swift responses - I've had another poke inside today.

It is 8 V AC and not DC - I was on a measuring frenzy last night and must have got confused, so apologies Janne for the misleading reply. The motor runs on DC but that is changed after it's come off the transformer. Voltage on the pins of a blown bulb (no load) partially fitted was hovering between 7.2 and 7.8 V AC. The switch for the lamp works in that it conducts when on and doesn't when off. There is only one brightness, and it is only powered when the motor is running. There is no supply voltage switch - they seem to have soldered the transformer inputs according to market region.

The bulb seems right - the manual specifies 8V 50W Halogen. The old bulb is marked 8VEFM50W // Sylvania on one side and 1705M next to the pins, the latter looks like a stamped batch number. My new bulbs are Philips type 6847 EFM A1/229 8V 50W GZ6.35. The old bulb had a bump on the rim of the reflector which fitted a notch in the projector to stop it from twisting in its mount which isn't on the new bulbs. It would be great if I have made a mistake in the new bulbs... sadly I suspect I'm failing to detect something gone wrong in the wiring.

Any further suggestions gratefully received.

Post by **VideoFred** » Thu Apr 13, 2006 7:48 am

I'm out of ideas, here

The only thing I can suggest is try a 12V bulb...
It wont do no harm.. just less brightness.
Are you sure the region is OK?

Fred.

Post by **Janne** » Thu Apr 13, 2006 11:11 am

First, make sure the wiring is ok.

The waveform of the voltage should be viewed with an oscilloscope. There might be high voltage spikes from the motor. Check the filters if possible.

Post by **Angus** » Thu Apr 13, 2006 11:46 am

merman wrote: The old bulb is marked 8VEFM50W // Sylvania on one side and 1705M next to the pins, the latter looks like a stamped batch number. My new bulbs are Philips type 6847 EFM A1/229 8V 50W GZ6.35.

A1/229 is also known as EFM...so "8V EFM 50W" is probably the same bulb.

If that is one of those lamps that has a bulb in the middle of a bowl shaped reflector, the older ones sometimes had a ridge for slotting into the projector's mounting whereas current ones usually do not...but it is a compatible lamp.

The only difference is the older ones would he Quarz Iodine or halogen...whereas the new ones might be different - but they've should be compatible.

So, is it possible for you to check for voltage spikes on the lamp terminals? Are you using a digital or analogue meter? Do you have access to an oscilloscope?

Sometimes there's nothing better than an Avometer Mk 8

Post by **Angus** » Thu Apr 13, 2006 11:49 am

oops double post

Post by **Sparky** » Thu Apr 13, 2006 3:31 pm

8V unloaded sounds too low- it will drop when loaded.
But I wouldn't have thought that it would cause the bulb to blow instantly like that!

Mark

Post by **VideoFred** » Thu Apr 13, 2006 3:56 pm

Sparky wrote:8V unloaded sounds too low- it will drop when loaded.
Mark

This is what I tought, too.
It should drop a lot. 2 Volt or something.

The only explanation left is: Voltage peaking...
Or wrong measuring...

Merman, are you shure these bulbs are realy blown out?

Fred.

Post by **merman** » Fri Apr 14, 2006 3:52 am

VideoFred wrote:The only explanation left is: Voltage peaking...
Or wrong measuring...

Merman, are you shure these bulbs are realy blown out?

I'm fairly confident in my measurements, but physics was never my strong point and it's a cheap digital meter, so it's possible.

I don't have access to an oscilloscope unfortunately. I'm not certain the bulbs are blown, but they seemed to blow in that they very briefly lit then went out when first connected, and do nothing on subsequent connections. I've a load of work to do over the weekend, so I'll probably guddle with the projector again to avoid working and go over measurements etc. Many thanks to all for the input... I'll let you know how I get on.

Filmshooting

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