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Author Topic: Elmo St1200HD M: No Sound
Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 12:03 AM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
Hi Everyone,
Been a browser for about a year now, since i first purchased an elmo st-180 from ebay that i got working from this great forum!
Thanx for your great advice!
Recently, I decided I would like another projector with some more bells and whistles and purchased another non-working poke-and-hope, the st1200HD M. Once i cleaned off the dreaded black goo from a couple pulleys and installed new belts, i was pleasantly surprised to see how much was working. I like lights and buttons. This thing is cool, and so much more hearty/robust looking than my st-180.
Anyways, the major issue I am having currently is no speaker sound at all. Searching and reading some other threads here, and following Steve's great advice to fiddle with the various sound related ports and buttons, especially the red rec button did not solve this particular issue unfortunately.
I tried plugging into the aux ports and such as well. I can hear sound when i try the monitor port(s), so what does that tell me i wonder? I can't imagine the speaker is bad or blown, it looks mint, but perhaps. I don't want to assume anything, but need help in the troubleshooting. I have the volume up and am in correct zone on the meter. I believe the yellow monitor port cuts off the signal to the speaker so i have made sure not to be in the ports when testing for sound. I am balanced between track 1 and 2, although pretty much all my films only have mag sound on channel 1. I can hear sound perfectly through the other ports, and can even hear sound(i tried in headphones again, they worked) if i plug into aux port by speaker. What am I missing? Help, and thanx in advance.
Matt

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Cheers,
Matt 📽

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Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003


 - posted December 10, 2014 12:18 AM      Profile for Winbert Hutahaean   Email Winbert Hutahaean   Send New Private Message       Edit/Delete Post 
If you have tested through monitor port that the sound is on, it means your projector has the sound board OK.

You are not in big trouble here.

What I can predict that the problem is very simple i,e the speaker problem. This can be easily handled.

Open the back panel (unscrewed).

Some projectors are not using wire but instead metals that touching each other when the back panel is closed. Check if the metals touch perfectly.

If your projector is using wires, check if the wiring is OK (nothing is cut).

If any of above does not solve your problem, you are pretty safe to use the projector using external speaker. This will deal your problem, and on the other side, you will get better sound!

You can direct hook up with the speakers (using external speaker output) or using external amplifier for even better sound (using audio output).

Many of us doing this..so don't be discouraged by not having sound from the original speaker...it is awful anyway! [Wink]

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Winbert

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Brian Fretwell
Phenomenal Film Handler

Posts: 1785
From: London, UK
Registered: Jun 2014


 - posted December 10, 2014 06:35 AM      Profile for Brian Fretwell   Email Brian Fretwell   Send New Private Message       Edit/Delete Post 
I have a Eumig D903 that went silent, I found after much checking that the mechanism that put the pressure pads up to make the stripe contact the sound heads had failed. That is one place to check I would say.

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Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003


 - posted December 10, 2014 08:15 AM      Profile for Winbert Hutahaean   Email Winbert Hutahaean   Send New Private Message       Edit/Delete Post 
No Brian, Mathew has said that he can hear the sound through the monitor output using headphone. So the head and the sound board are OK.

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Winbert

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 08:41 AM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
Thanx very much for the replies! You guy can feel free to call me Matt, as my friends call me!
Winbert, you are correct that i hear sound through the monitor ports. I should mention that although ext speakers can be used, I would like to see if I can repair the standalone unit if possible.
I always like to put things in the type of order that I can re-sell it if need be, and although people may buy without the speaker working, I would like to get it working- if at all possible.
Winbert, What i also tried last night was alligator clips. If i can figure out how to upload these 4 pics i took, i will, and all can see that i have the 'metal prong' contact system. I was thinking what you were, that is, that good contact wasn't being made, so i tried with the alligator clips, but i hear absolutely nothing, not even a rustle through the speaker. Can i test the speaker somehow. I just can't believe this new looking speaker is blown. Maybe a resistor or something? I am technical but need help in how to properly test, where to put my voltmeter contacts etc....if anyone can help with that, i'd be most appreciative!!
Thanx very much,
Matt
 -

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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


 - posted December 10, 2014 08:52 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
Hi Matt,

The speaker is a regular 8 ohm speaker, so you should be able to kludge in any reasonable power audio signal and get sound. (operative word: "should")

My guess? The Aux. jack on the rear panel disables the speaker when a 1/8" phono plug is inserted. Try plugging and unplugging this a few times and see if maybe there are oxides on the bypass contacts that will break and hook you up again. This is a good bet on a machine that has been unemployed for a while.

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

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Martin Jones
Phenomenal Film Handler

Posts: 1269
From: Thetford , Norfolk,England
Registered: May 2008


 - posted December 10, 2014 09:07 AM      Profile for Martin Jones   Email Martin Jones   Send New Private Message       Edit/Delete Post 
Matt,
A faulty speaker CAN,and normally WOULD, look as if if had nothing wrong with it. So, BELIEVE!

The simplest check is this...
You mention a Voltmeter. If your "voltmeter" also measures resistance, set it to a low resistance range. Then remove the back cover of the projector so that it is no longer connected to the projector, and apply the two leads of the "voltmeter" to the two connecting tags ON THE SPEAKER .
If the speaker is OK, you will hear a click in the speaker and the meter will indicate around 4-5 ohms (value not critical).

Conversely, no click, no reading,... faulty speaker.

It really is that simple to test a speaker works.

--------------------
Retired TV Service Engineer
Ongoing interest in Telecine....

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 09:32 AM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
Thanx very much for the additional info folks!

@Steve, I will try what you are suggesting further.....I feel it must be a bad port somewhere. btw, when i plug my headphones into the yellow monitor port, i only get the left ear unless i fiddle and can, with work, get both ears working. I am wondering if this port is oxidized like you say or what further i can do to make sure it is NOT this port causing the speaker to shut off...

@Martin, thanx so much for walking me through that. I always wanted to figure out how to use this voltmeter better [Smile] Believe it or not, the speaker makes the beep and shows a resistance of 7.8 -8.0.
This was trying it right at the speaker where the black and white wires attach to speaker....if i go further downstream and try it on the 2 metal prongs that will make contact with the board, i hear nothing...not sure if i should hear there? I think we are narrowing the potential issue, but still need a hand-hold!Sorry for my persistence. I am an egghead when it comes to Super 8 stuff. I like to get it working [Smile]
Thanx very much!
Matt
 -
PS: I tried to upload 2 diff pics, but for some reason it overwrites the next pic with the previous. Just in case anyone wonders why my pics in 2 posts are the same. arghh..

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Cheers,
Matt 📽

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Martin Jones
Phenomenal Film Handler

Posts: 1269
From: Thetford , Norfolk,England
Registered: May 2008


 - posted December 10, 2014 09:53 AM      Profile for Martin Jones   Email Martin Jones   Send New Private Message       Edit/Delete Post 
Yes, you should hear it there as well. So whatever is in the wiring between the springs and the speaker is the source of the problem.
I'm not familiar with your ST1200HD, but the schematics I have for the ST1200 show that the speaker wires go directly from the spring contacts to the speaker. If this IS the case.... and you get a reading on the speaker connections but NOT on the springs then there is a "break" in one of the wires, or a bad joint.
Try this....
Put one lead of the voltmeter on one of the springs. Put the other on one of the loudspeaker contacts. If you get a reading (with or without a "Beep") then the wire from that spring to the speaker is OK. If not, try the other spring with the same speaker connection. Same reasoning applies.

--------------------
Retired TV Service Engineer
Ongoing interest in Telecine....

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Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003


 - posted December 10, 2014 09:57 AM      Profile for Winbert Hutahaean   Email Winbert Hutahaean   Send New Private Message       Edit/Delete Post 
Matt,

I cannot give the exact answer without having the projector right in front of my eyes. What I can give is a tinkering way to make the original speaker to loud the sound as you wish. So I would suggest (if what other members have said was not helping) to hook up the speakers to the external speaker port through wires.

quote:
PS: I tried to upload 2 diff pics, but for some reason it overwrites the next pic with the previous. Just in case anyone wonders why my pics in 2 posts are the same. arghh..
This can happen if you give the same EXACT file name for both pictures. You must make something unique. Please also not to give a name that other people tend to use to, such as picture01, etc, because other members can also override your picture if he/she later upload a picture with the same file name on different posts.

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Winbert

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Steve Klare
Film Guy

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


 - posted December 10, 2014 10:13 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
On the ST-1200 HD there is a circuit board inside the side panel that provides for the Aux jack and the external speaker port: plenty of opportunities for mischief there...

Matt, all of the phono jacks on ST-1200 are monaural ones. If you plug a stereo plug into them you should only hear the left channel because there is no right channel contact. If the right channel is coming up it's because you are somehow wiggling that ring into contact with the monaural "hot".

The HD is a strange beast: "Twin Track" but not really "Stereo", two channels, one speaker. -"stereo capable", but only with supporting hardware.

-As a matter of fact I'm messing around with stereo on mine this week.

BTW: Have you tried plugging an 8 Ohm speaker into that DIN socket?

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

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Martin Jones
Phenomenal Film Handler

Posts: 1269
From: Thetford , Norfolk,England
Registered: May 2008


 - posted December 10, 2014 10:33 AM      Profile for Martin Jones   Email Martin Jones   Send New Private Message       Edit/Delete Post 
Thank you Steve. If that's the case, my last suggestions\ will not help.
However, if trying Steve's simple checks of working the sockets (AUX and EXT SPEAKER) with the relevant type plugs to remove oxidation do not work, then I would caution you (as your knowledge of electronic wiring is minimal) not to try any soldering or further disassembly work, but hand the rear panel assembly over to an electronic technician for troubleshooting.
The relatively simple wiring and sockets should be a "doddle" to such a person, even without a schematic.

--------------------
Retired TV Service Engineer
Ongoing interest in Telecine....

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 10:41 AM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
@Winbert- I really appreciate your help and realize how difficult it is to troubleshoot on the internet. You have been magnificent! Thanx for the pic naming tip as well. I lazily named them 1,2,3,4, so have rename them unique. If you scroll up now, you will see different and better pics of the open unit.
I have hooked up an older computer speaker system i had sitting around and it works, in mono, so I have a backup while working on this other speaker! Thanx!
@Steve- Ahhh! So that is why- he hee. Well, I'd better not try to 'force' stereo any further. I was going crazy thinking the ports were not taking my 1/8th jack properly. Thanx for clarifying that for me! By Din socket, do you mean the ext aux 1/8th beside speaker? If so, then yes. I have tried any 1/8th port to try to clear them out in case they were oxidized. What i cannot try however currently i the other port at back beside the 1/8th..i think it may be for elmo's proprietary speaker which may have another connector? I don't have anything to plug in to that one....
@Martin - I will try what you suggest very soon..i just have to run out to get a haircut with my kids, but cannot wait to try more when i get back. You guys are amazing! btw- the post above, i have uploaded a proper pic of the open speaker back now so you can see what i have... It looks like it is connected to some things, including 3 resistors. Is there a way to test these resistors? Sorry, i did this in highschool but forget alot about voltmeters now and don't want to fry anything. I appreciate your patience with me!! ps, just read your last post to Steve, so i will read closer to see what i shouldn't do....Thanx.
Regards,
Matt
 -

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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From: Long Island, NY, USA
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 - posted December 10, 2014 11:06 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
The DIN speaker socket kind of looks like a tiny North American power outlet, except one slot is a lot longer then the other. It is black, maybe 3/4" in diameter.

This is the same signal that would normally go to the internal speaker. The phono jack is a line level signal, good for inputting to an external amplifier but not for powering a speaker.

"External Speaker" should also have a bypass for the internal speaker: another possibility.

Let's get "monaural" working before we go all stereo. Life is complicated enough at the moment!

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

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 11:41 AM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
Thanx again Steve.
Back home now...Do you think that perhaps this Din port could be the culprit if it is oxidized? I don't have a proper plug to try it out...is there any other ways to test that port or to clean it otherwise?
Thanx,
Matt

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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From: Long Island, NY, USA
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 - posted December 10, 2014 11:48 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
I can't rule that out.

The DIN plugs are few and far between over on our side of the Atlantic these days. I swear I remember them at Radio Shack when I was a teenager (-been a while!), but if you show them one these days they ask "What operating system supports this???!!!". One electronic part distributor I know sells them, but stock them in the UK, so you wait, and you pay to ship.

Steve Osborne sells them.

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

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 12:01 PM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
I wonder if Remi TV here in Hamilton has something.... They are the only oldschool place i know that is reliable anymore.... Once i know for certain what it may be, i could try to find out...
I've created a closer picture and photoshopped the front in so we can see everything at once.
 -
See these 3 resistors...should i be getting a resistance reading and beep across these? What's weird is i get no beep across any of them, but if i touch the left side of the top resistor and the right side of the second one down, i get a beep...nothing else beeps. Just thought i'd add this info in case it is meaningful [Smile]
Thanx,
Matt

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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From: Long Island, NY, USA
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 - posted December 10, 2014 01:01 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
I would imagine those resistors would be pretty low in value, they should certainly show something on your ohmmeter. They look like they are OK and short of frying, resistors basically never fail.

The DIN connector is the one that looks oval from the rear.

What's important here is that both of these jacks have three terminals: one is signal, one is ground and the third should be some means of controlling the external speaker, probably a switch closure to ground that gets opened up when an external connection is plugged in.

Do you see a short between any two of the three terminals with an ohmmeter?

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

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Martin Jones
Phenomenal Film Handler

Posts: 1269
From: Thetford , Norfolk,England
Registered: May 2008


 - posted December 10, 2014 01:01 PM      Profile for Martin Jones   Email Martin Jones   Send New Private Message       Edit/Delete Post 
You can safely ignore the Aux Out socket and the resistors, which are there to reduce the "speaker" level signal to the level required for Aux Out.
The presence of the DIN socket indicates that this machine was intended for use in Europe, where DIN is a Standard for Audio connection different to countries influenced by North America.

The speaker circuit should be simple. The wires from the spring contacts should go first to the DIN socket, which provides a means of connecting an external speaker. It also contains an internal switch, operated by insertion of the plug, which disconnects one of the wires that go on to the speaker.
By this means, when an external speaker is connected, the internal one turns off. If we could get a clear picture of where the wires go and how they connect between spring contacts, external speaker socket and speaker it would be possible to give clear instructions as how to locate the problem (and hopefully cure it)

--------------------
Retired TV Service Engineer
Ongoing interest in Telecine....

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 01:58 PM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
Thanx again.
@Steve - I am uploading a closer pic of the three terminals so we can see them. The middle one, white, it's post seems very wiggly where it goes into the oval back. I am not sure if it has a short yet however. What should i be touching the other end to on the ohmeter? The black? When i touch it to the black while testing this middle white, i hear a beep. I hope i did that correctly?  -
@Martin - I tried to take a better side view pic to show where the wires go. Not sure i would be able to get a better shot under. Does this pic help?  -
Thanx so much guys! I think your right that it might be this ext speaker jack somehow possibly.

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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From: Long Island, NY, USA
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 - posted December 10, 2014 02:06 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
here's my guess:

-The purple wire is chassis ground (-or will be once everything is assembled).
-The orange wire should be shorted to the purple with the Aux unplugged.
-The white wire is the return line from the speaker.
-The white wire should be shorted to the orange wire with the external speaker unplugged

The yellow wire is Aux signal
Black wire is speaker "hot".

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

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 02:25 PM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
-The orange wire should be shorted to the purple with the Aux unplugged.

Beeps!

-The white wire is the return line from the speaker.
-The white wire should be shorted to the orange wire with the external speaker unplugged

No Beep!

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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


 - posted December 10, 2014 02:36 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
Hmmmmmmmm....

How brave are we here?

("There are old pilots, there are bold pilots, but there are few old, bold pilots")

It's always nice to try things with low (or NO) power before you go full blast.

Try this:

1) Measure the resistance between those two wipers that connect to the rest of the projector.

2) Apply a jumper between the orange wire and the white wire.

3) Repeat that same ohms measurement

See if when you do you find that 8(ish) Ohms shows up at those contacts.

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

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Mathew James
Jedi Master Film Handler

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


 - posted December 10, 2014 02:50 PM      Profile for Mathew James   Email Mathew James   Send New Private Message       Edit/Delete Post 
He hee- I'll try anything with no power [Smile]

1) Measure the resistance between those two wipers that connect to the rest of the projector.

No Resistance shown when measuring these two wipers

2) Apply a jumper between the orange wire and the white wire.

Ok, done.

3) Make the same ohms measurement

now I get a reading which seems to hover with my unsteady hands between 8.4 and 9.6.

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Cheers,
Matt 📽

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Steve Klare
Film Guy

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


 - posted December 10, 2014 03:22 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
OK,

By "No Resistance" do you mean an open circuit?

If so, this is looking like the external speaker jack is flaky.

You could solder a TEMPORARY jumper across the orange and white terminals on this connector, with my promise that you WILL blow up an amplifier IC if you plug in an external speaker before you fix this for real and I think after the jumper is in place the internal speaker will work again.

Just remember: this is a kludge and you need to fix it for real or promise to forsake external speakers as long as you shall live!

(Be nice: don't sell the machine this way, either...)

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

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