8mm Forum: Eumig S910 fuse problem

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Posted by Brian Collins (Member # 761) on July 07, 2009, 12:02 PM:

Have a problem with my Eumig S910 as the sound was not working properly, on investigating I have found that when the sound is there and I move the volume control about I loose all sound and then discover that the 2amp fuse on the cicuit board has blown, on replacing it I then get the same problem. 4 fuses so far so have stopped trying, can anyone throw any light on why this should happen, it is a volume and tone control unit but only seems to be the volume pot that is the trouble. there is quite a lot of movement on the shaft. I suppose spares would be out of the question. Any advice please.

Posted by Simon McConway (Member # 219) on July 07, 2009, 02:43 PM:

John White has sorted out my Eumigs over the past few months www.the8mmshedshop.co.uk

Very good service and very reasonably priced.

Posted by Colin Edwards (Member # 183) on July 09, 2009, 08:36 AM:

Hi Brian, Simon is quite right, John White is a Eumig engineer, and worked
for many years for Johnsons of Hendon the Eumig distributors in the Uk.
Iam lucky that I live just five minutes away form him, and he has repaired
my Elmo st1200 and Eumig 940 for me at a very fair price I know that
Ian from Perrys uses him for all his repairs he also has a lot of Eumig
spares, also Bill Parsons is a good engineer and he lives in the south east.

Posted by Martin Jones (Member # 1163) on July 09, 2009, 08:53 AM:

Brian,
The Volume control part of the assembly could not cause a fuse to blow by just turning the shaft, unless the Volume/Tone assembly also includes a mains On/Off switch on the same shaft as the Volume control part. In a case like that, a faulty switch could short and cause problems.
It is more likely that when you move the volume control, the board on which it is mounted also moves and makes a live part of the circuit contact the metal body of the machine. Check for any board movement; tighten mounting screws etc. and make sure that any sheets of insulating material are in place between electrical parts and the metal body. I don't have that model so cannot advise you any less generally than that.

Martin

Posted by Brian Collins (Member # 761) on July 09, 2009, 11:24 AM:

I have now removed the back and disconnected the speaker and if I run it and move the control it does not blow the fuse but on reconnecting the speaker it will play fine for about 20 seconds and then I see the fuse blow and I did not touch the control, it appears to only blow when the speaker is connected and runs for a few seconds but connot see why.

Posted by Martin Jones (Member # 1163) on July 09, 2009, 12:16 PM:

Interesting Brian! When you say it plays fine; is that with soundtrack or similar coming through clearly? Can you scan the circuit diagram (most Eumigs publish it in the User Book) and send to blagdonian(at)btinternet(dot)com ?
Martin

Posted by frank arnstein (Member # 330) on July 11, 2009, 03:12 AM:

Hi to the posters on this thread..
With regards to this problem, At Projector Heaven I service a lot of Eumigs and have found nearly all problems with sound ends up being a result of oxidisation occurring within the long sliding record/play switch located on the motherboard. It has many contacts inside and they become oxidised with time. Then all sorts of weird symptoms appear with the sound. The fix is simply to operate the record switch, on and off many times, with a liberal spray of switch cleaner onto the entire length of the switch block to flush it out. This will clean the internal contacts and magically restore the great sound we all expect from our Eumigs.
Hope that works for you too...
dogtor pufferfish

Posted by Brian Collins (Member # 761) on July 11, 2009, 08:11 AM:

Thanks Frank,I have stripped and cleaned the slider and that has made no difference, It only blows now if any speaker is used, internal or external, if I plug in the external plug with my lead to my mixer deck into my editing system it works fine, but blows when connected direct to any speaker.

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