8mm Forum: Elmo ST800 Sound Problem

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Posted by Janice Glesser (Member # 2758) on September 12, 2014, 01:37 PM:

The audio output level through the speaker has always been very low on this projector. However running it last night I couldn't hear anything coming out of the speaker. I then hooked it up to an external speaker. I could then hear the sound track...but very faintly. Mostly I heard a very load humm.

The projector is running great otherwise...I just hope I can figure out what's going on with the sound. Any ideas or suggestion on things I can check?

Posted by Lee Panton (Member # 4443) on September 12, 2014, 01:49 PM:

Janice you could try cleaning the sound head with tiny amount isopropyl alcohol.

Posted by Steve Klare (Member # 12) on September 12, 2014, 02:07 PM:

Here's something that worked for me on this machine:

Get a 1/8" phono plug (a headset should do) and plug and unplug into the various audio jacks a few times. The jacks have an integral switch to bypass the speaker and it can build up an oxide which will keep the speaker off all the time. My best bet here would be the "Aux" jack, but I bet you'd be happy if any of them was the culprit!

When I first got my ST-800 it was dead silent until I did this. I was actually just trying to troubleshoot it and wound up completely fixing it instead.

-work the red recording switch too, it's also one of the usual suspects.

Posted by Janice Glesser (Member # 2758) on September 12, 2014, 02:59 PM:

Oh Steve...I could kiss you [Smile]

That worked!!! It's a miracle! I don't know which socket was the culprit...I did both the aux and the headphones...and then monkeyed the red switch up and down. The sound miraculously returned.

....and as an added benefit...the sound through the speaker is also much loader now. Looks like this was a problem from the time I bought it. I'm so excited because this is one of my favorite projectors.

Thank you so much [Smile]

Posted by Steve Klare (Member # 12) on September 12, 2014, 03:25 PM:

Shucks, Maaam!!!

No miracle! It's just kind of a genetic weakness of these machines!

What this is about is metals on switch contacts oxidize and build up an insulating film. Above a certain voltage level the film can't withstand the voltage when the switch is closed and it ruptures and the switch works.

-but when you have some wimpy low energy circuit like a low level audio signal it can just continue to build up until you have to clean it off. That's what you just did.

-if the manufacturer was willing to use gold plated contacts it wouldn't happen...but($$$)

Where I work we have a couple of hundred power supplies operating, and recently they started to flake out. We'd take them out and test them on the bench and they'd be fine again. After a lot of head scratching it turned out to be exactly the same problem. (Not just ELMO!)

They'd turned off the switch before they removed them from the racks and I'd turn it on again after I hooked them up for test.

-film busted, works fine! (STOP sending me these!)

We just ordered 300 gold plated switches and are now installing them.

Posted by Vidar Olavesen (Member # 3354) on September 12, 2014, 03:34 PM:

Don't remember if you suggested that on the Sankyo Stereo 800 I had too. It worked fine just switching the speed from 18 to 24 many times, now it runs correctly :-)

Thanks to whomever it was that suggested check the switch

Are you happy with the projector then Janice? I am wanting a ST-600 myself, a black one, same as I had when I was 11 :-) Miss it a bit

Posted by Janice Glesser (Member # 2758) on September 12, 2014, 03:43 PM:

Steve...you are too modest. I appreciate that you took the time to reply and offer your knowledge and experience. To me it is a miracle...it didn't work...and now it does [Cool]

I love everything about this projector Vidar. It purrs like a kitten when running...easy to clean...smooth steady picture...and I love the black color... very sexy [Cool]

I had an Elmo ST1200, but sold it. It ran fine, but I just didn't like that poopy green color. I've never had a ST600...but I'm guessing it would be about the same...just maxing at 600ft reels.

Posted by Steve Klare (Member # 12) on September 12, 2014, 04:02 PM:

Actually my ST-800 is what I call my "Desert Island Projector": basically if I can only have one, this is the one I choose.

(...and a generator!)

It is among the simpler Elmo machines, so it is reliable. It doesn't do as much, but what it does it does very well.

Posted by Andrew Woodcock (Member # 3260) on September 12, 2014, 04:03 PM:

Well done Steve, superb advice and looks like you have one hell of an admirer now! [Big Grin]

Posted by Pasquale DAlessio (Member # 2052) on September 12, 2014, 04:14 PM:

Rejoice! For today (or whenever) a miracle has been witnessed! Lo and behold Janice's sound in now working. For the lord Steve has worked his powers once again. It is a true miracle in the projector world. Tis surely a glorious day.

Hail Steve the almighty the god of projectors!

Posted by Steve Klare (Member # 12) on September 12, 2014, 04:20 PM:

Remember: "Film Guy"...not "Film G--"!

The late, tense nights before prototype deadlines have proven that more than a few times! ("Dammit! I coulda been an accountant!!")

I think this should almost be a sticky in this Forum. It's actually a very common ailment. Years ago I wanted a favor from somebody that was selling a mute projector and I bribed him with this information. It worked then too!

Posted by Terry Sills (Member # 3309) on September 13, 2014, 10:18 AM:

Hey Pasquale
No politics or religion!!!!

Posted by Steve Klare (Member # 12) on September 13, 2014, 10:52 AM:

Yeah!

Especially one with such a fallible "god"!

(I spilled coffee on myself at work the other day!)

Posted by Janice Glesser (Member # 2758) on September 13, 2014, 11:37 AM:

Hey Steve....Spilled coffee?...I broke a nail!

Posted by Clay Smith (Member # 4122) on September 13, 2014, 02:54 PM:

Oh my gosh. I just fixed one of my projectors with that advice. Thank you Steve.

Posted by Andrew Woodcock (Member # 3260) on September 13, 2014, 04:05 PM:

Steve gives off great electrical sound advice regularly. It is fantastic when his excellent knowledge comes to fruition for others on here.

Posted by Mark L Barton (Member # 1512) on April 24, 2019, 03:41 PM:

Steve, you are a steely eyed projector man. It worked immediately on one of the st1200, booming clear sound was heard from a projector that l thought would never play again from a mag stripe. The second one has the whine and no mag audio, l cleaned the sockets but noticed that when l pushed in the red record button the whine went, with a Mic plugged in my voice wad heard thru the speaker. So, lm guessing the red rec button is at issue here. I have used servisol contact switch cleani g spray but Zippo yet. Any thoughts my gifted friend? Oh and cheers for all your advise.

Posted by Steve Klare (Member # 12) on April 24, 2019, 03:53 PM:

quote:
-a steely eyed projector man

I LIKE that! Where can I get a T-shirt made?

-although Leon Norris probably has much steelier eyes than me! Where projector repair goes I'm basically a hobbyist who happens to be an Engineer.

Regrettably, your Whiner sounds more like the one I had which only got better when I replaced the pre-amp ICs.

I think when you depress that switch you disconnect the amp from the head. Maybe the whine really is still there, but you aren't hearing it any more.

Posted by William Olson (Member # 2083) on April 24, 2019, 09:45 PM:

I, too, find the Elmo ST-800 to be one of my favorite projectors. At this time, the 2 speed pots on my machine broke due to my own carelessness and I had to remove them. Any suggestions on how to replace them would be helpful.

Posted by Leon Norris (Member # 3151) on April 25, 2019, 07:10 AM:

Always keep your switches and inputs clean! With tuner cleaner with Lubricant! I use this works just fine! And you won't have these problems!

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