Unfortunatly, this evening, my Eiki SL2 appears to have developed an odd sound fault. The sound is all there but there seems to have what i would call, a pulsing hiss, the hiss comes with the sound as opposed to an on/off pattern and is only when film is going through, there is nothing abnormal when there is no film, just the usual light hiss at full volume. There is no problem with wow and everything else seems to function fine.
We noticed it last Thursday on a trailer when my Brother said, is that pulsing hiss on the film. Tonight i tried several shorts and it is the projector, all projected films had this pulsing hiss, it is easily heard but more so with music.
Any ideas anyone? Looks like another pack up and send job!

No idea Tom, cant say I've ever heard that before when running 16mm. Just to rule it out though I would try cleaning the Optical section of the lens/photodiode and the bulb using a cotton bud and some Solvent Cleaner or similar.

Another thing you could try is to plug in headphones to see if its the amplifier (can't remember if there is a separate low power socket for this).

Graham S

Thanks Graham, i will try the headphones later, it is hard to describe the sound but it is noticable. I did try the built in speaker and is also heard through here which rules out an external amp fault.

Tom,I don't mean to teach you to suck eggs etc,but here is a list of possible causes:
Defective exciter lamp
Speaker Defective
Lateral guide roller seized or binding
Sound drum bearing defective
Flywheel off
Flywheel too loose
Defective amp
Optic lens misaligned
Dirt / Emulsion /glue from tape joins / Anything that will stick to sound drum ,on said drum
These are some suggestions from the service manual .I'm sure you have already checked /cleaned everything in site but thinking before you send.

This is a Super Slot Loadar and a lot of things happen when you turn the control knob.
Various parts move to place the film in their correct positions.
So, with yours, I suspect that the film is not being located correctly around the sound drum, and some exciter light is picked up away from the sound track.
I suggest you remove the two side covers and watch as the film is loaded, paying attention to the sound section.
This may show what is wrong.

Thank you all for your replies, much appreciated. I will be taking a look later but am still getting good information. Hopefully will update as I go.

All of the above look good, possible amp fault but sill update as soon as I find out.
Film is tight around the drum, no dirt on the or around the optical lens or drum, film is on the path as it should be, flywheel find and tight as it should be.

Tom,

Have you ever thought of fitting a line out and using an outside amplifier, my brother Michael back in the day did a couple of 16mm machines for John Bird when he was doing his film shows, I'm sure someone could fit one for you, just a thought, of course!

Hi Barry, all 8 and 16mm fims are viewed with sound via an amplifier.
I couldnt go back to just using an extention speaker.
The noise on this machine is thete both via the amp and also the built in speaker when i needed to chech it wasnt my amp.
The amp is connected via the 6.5mm jack plug on the projector.

I had to look twice there tom, i thought it said "space odyssey " ...... take your protein pills and put your helmet on ........

Oh dear, my sausage fingers on the phone again

I'm no electriacian, if you're getting the hiss on both the built in speaker and through your amplifier, I'm guessing that it's something in the pre-amp circuit that's breaking down,these are very old machines now, perhaps a smoothing condenser is giving up the ghost, I know your quite technical on super 8 Elmo's, what are you like on 16mm projectors?

Ive only ever looked at the basics myself, anything electrical i leave well alone. I have all the service books but again, even though the electrical side is well covered in the books, you need the expetise to sort these proplems out. The service manuals are great as you can see how everything is fixed and there are sympton and how to fix lists, but you try having a go though with those very fine adjustments.
The mechanical side on 16mm machines is more easily sorted due to their ease of access compared to most super 8s. Hopefully, i may find out a little more over the weekend.

One thing Bill mentioned to me many times over the years, is how he would cringe when people mention adjusting head alignments on 8mm machines snd the photocell on 16s. These are factory set with screws secured with special glues. They have no reason to ever need touching unless its for replacement of worn units, they cant move on their own.

Tom,

My brother Michael asked if you were getting any noise when you turn the sound control, the pot could be playing up and giving feedback, you could use some cleaning fluid first and see if it makes a difference!

Thanks Barry, thats all ok on this one, all pots well cleaned.

As an update on this sound issue, it looks like it is a fault in the amp, one was sent to me for a trial, all fitting in today and is all good again.
It'll be interesting to see if the fault will be found once my amp is sent back.

Tom,

Thanks for sharing this issue with the rest of us. It is only a matter of time till it crops up on someone else's projector (but lets hope not).
I am curious what will be found.

Me to Greg, i will update as soon as i find out, it will depend on if the amp im returning wirh fault can be fixed without a projector to test. (I think)

Glad you got it sorted Tom,will be interested to know the fault in due course.

Thanks Gwyn & Greg,

And my source once again is the real Mr Elmo, Bill Parsons.

Bill read my problem on here and contacted me by email to say dont send it away yet, he gave me a few things to try which I did, one being to turn the projector in forward with no film, put the volume up high, and spin the flywheel in the normal direction, if it was a fault in the drum area then this pulsing noise would have been present with this test but It wasn't.

Bill talked me through a couple of other possible areas to explore. He was trying to help me avoid having to send the machine through the postal service. As the few possibilities were exhausted Bill said that he had a second hand amp for the SL2 projector within his stock which he knew to be working. While mine is the optical magnetic version, I have no magnetic sound films so I couldn't really care less if my projector was switched over to an optical only machine, after all, 99% of 16mm projectors are optical only. That being the case, Bill offered to send his amp to me to try. Today I fitted it and the machine is now A1 again proving the fault to be within the amp. My faulty one will go back to Bill now to see if he can find the fault but this my not be so easy without the projector, (or A projector) to try it on but there is a few tests he can do.

Once again I have to thank Bill, the master projector technician, for helping me sort a problem which otherwise would have cost me a pretty penny in just postal services alone.

Even in retirement, Bill continues to keep our machines rolling. it isn't just the new releases that keep the hobby going, it's being able to keep the projectors in good working order, without the projectors, the films are useless. I often think it is underestimated what a handful of engineers have done for this hobby, but none more than Bill, even in retirement his wealth of product knowledge and know how is simply outstanding.
When forum member's pat people on the back for copying digital to film for a small fortune, lets please not forget what Bill has done for so many over the years, many of whom have gone onto forums and used his advise they have recieved in conversation and taken the credit themselves, something I would never do. We would have left the hobby years ago when projectors caused us problems, but here we are in 2023 and ALL of our projectors are in pristine condition thanks to Bill. Where else would I have got an amp just to try first? Where would i have got heads for my Sankyo 880, the new film gate for my 1200HD, just to mention a very few items?
It's very good to have a go yourself with the basics but it is most definatly the experience and knowledge that is most important.

Cheers again Bill.

Glad your up and running again Tom, Mark

Tom,

Your post highlights an extremely important reality. As you point out, many of us are sometimes focused on prints more so than our projectors. As great as new prints are, we are DOA if our projectors are inoperable.

It is wonderful that Bill Parsons continues to share his expertise. He has helped me in the past, and he really is a electronics genius.

I am curious what percentage of problems with our projectors are sound related (amp, pre-amp etc.) and what percent of issues fall into other parts of the projector.

Do you have any thoughts on that based on your experience? With projector repair expertise so incredibly rare nowadays, I am thinking that perhaps instead of trying to repair/trace issues with older amplifier boards perhaps there are other, more current solutions that could solve at least some of these issues? In other words, instead of trying to trace and repair these old boards, is it at all possible that a newer amplifier board could be patched in to connect up with our older projectors?

I am hopeful about this is a possible option to explore, but sadly I am not currently knowledgeable enough about things like Raspberry Pi but I do know there are amp boards available using this OS. The more critical question would be how to marry a new board to an older projector's audio process....

Food for thought at least, and perhaps someone smarter than I (like Eivind!) may have some thoughts to share.....

https://www.raspberrypi.com/documentatio...ries/audio.html

Kind Regards,
Greg

I would like to add to Tom's post regarding Bill Parsons.
This gentleman has helped me on numerous occasions to sort out problems with my projectors,his advice is invaluable and his help in finding solutions to problems is scond to none.
Thank you Bill for all you do even in retirement.

Greg, It is a good point you make regarding what the majority of faults are. With mechanical faults, many people can find a solution, the eiki range in particular are so easy to take apart and service. This was clearly one of the aims of the company in designing them. Home repairs become almost impossible when there is an electronic fault for obvious reasons, if your not experienced in this field then you have little or no chance apart from replacing an entire part, in my case, the amplifier.
As for your question on using something modern to match in, that is a good question which is beyond my own thoughts but the next time I speak to Bill I may ask for his thoughts on this and report back.
I sent my amp to him on an exchange basis so it till be interesting to see if any faults are found as I dont think he has an SL2 to try it on.
Tonight I viewed reel two of All this and WW2 and the sound is booming through the amp now with no pulsing his with every word.