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Author Topic: RT1 Niggles
Robert Pitman
Junior
Posts: 24
From: Wales, UK
Registered: Mar 2007


 - posted April 16, 2007 07:25 AM      Profile for Robert Pitman   Email Robert Pitman   Send New Private Message       Edit/Delete Post 
Aquired an Elf/Eiki RT1 and got a coupla minor niggles that I hope someone can help with:
1. The lamp only works on full and not on half strength. It does not work in reverse either. Is this likely the switch?
2. Some wobble/play in the take up reel bearings. Can these be replaced/are these available or is it likely the belt?
3. Hum when machine turned on. I know this is an old machine but is there anyway of rectifiying it?

Like to add that I love this machine complete with niggles. It's very easy to work on and as other members have said "Is built like a tank".

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Why do transformers hum?
Because they don't know the words.....

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John Whittle
Jedi Master Film Handler

Posts: 791
From: Northridge, CA USA
Registered: Jun 2003


 - posted April 16, 2007 09:18 AM      Profile for John Whittle   Email John Whittle       Edit/Delete Post 
Robert,
Since this is an Elf, there may be slight differences between it and the US Eiki model but anyway--
1. There are two taps on the transformer for the lamp. One at 22 volts and one at 24 volts. If a lead is broken or not connected, then that would account for no lamp at one level. You'll have to track it back from the hi/lo switch to the transformer. Also the hi/lo switch might be bad. No lamp in reverse is a bit strange, but it would likely be the micro switch that is cammed on by the rotary switch. Kinda a mess to dig out and work on.
2. Wobble in the take-up reel is likely the clutch piece (the cork lined drum that rides on the steel drum) either in the cork or the shaft being worn. There is a bushing in the reel arm that should allow a slight amount of play, but not wobble. There should also be a washer under the screw that holds the piece in place. It that's missing, then you'd have excessive play/wobble. That's a special piece so you'd need parts for any of these things if they're bad. Unlikely it's belts. The belt BTW should be clean and dry, the inner cork liner should be lubricated with phonolube (a light grease which was widely used on record changers--if you remember those).
3. Hum is a bit more difficult to track down, but try this. Block the exciter lamp from the pick up when you turn it on. If that solves it, then there is a bad cap in the exciter lamp circuit. It's just as likely that a cover isn't fitted properly and you're getting some ac bleed to the solar cell. There were several different designs of amps used in these over the years and hopefully you have one of the later ones that used descretes for the power stages (the big integrated amps are basically trash if they go). You'll need a schematic to trace it out once you locate the cause as either the exciter lamp circuit or the amp itself. Likely a bad cap in the early stages or the rectifier stages. I think this was the first Eiki that actually had a regulated dc supply to the exciter lamp, if there is a part bad there, then the hum should stay on, if it goes away, then look for a bad shield letting light hit the solar cell.

John

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Robert Pitman
Junior
Posts: 24
From: Wales, UK
Registered: Mar 2007


 - posted April 16, 2007 02:52 PM      Profile for Robert Pitman   Email Robert Pitman   Send New Private Message       Edit/Delete Post 
Thanks John for the detailed checklist.
In regards to the Hum, could you be so kind as to explain "Block the exciter lamp from the pick up when you turn it on" to a complete novice.

As a further note to the hum, the hum appears even when the main and exciter bulbs are not lit i.e. in standby mode.

Rob

--------------------
Why do transformers hum?
Because they don't know the words.....

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Jim Latendorf
Junior
Posts: 13
From: Sacramento, CA.
Registered: Dec 2005


 - posted April 17, 2007 02:24 PM      Profile for Jim Latendorf   Email Jim Latendorf   Send New Private Message       Edit/Delete Post 
John is basically saying to take a piece of cardboard and place it between the lamp and the audio pickup lens and see if the hum goes away. It it does, then the lamp's power supply is modulating the exicer lamp's filament. A machine this old might be due for capacitor replacement. Capacitors dry out over time causing these symptoms.
--
Jim L.

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Robert Pitman
Junior
Posts: 24
From: Wales, UK
Registered: Mar 2007


 - posted April 17, 2007 05:16 PM      Profile for Robert Pitman   Email Robert Pitman   Send New Private Message       Edit/Delete Post 
Thanks for that.
Will give this a go over the weekend.
Rob

--------------------
Why do transformers hum?
Because they don't know the words.....

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Kevin Faulkner
Film God

Posts: 4071
From: Essex UK
Registered: Jun 2003


 - posted April 18, 2007 04:03 PM      Profile for Kevin Faulkner         Edit/Delete Post 
I think that Robert may be talking about a hum from the mains transformer.

Mine buzzes as soon as I apply power to the machine but all voltages are ok. I think these mains transformers are of poor design and prone to buzzing. I cant hear when the machine is running as the motor noise etc drowns the buzzing noise out.

Kev

--------------------
GS1200 Xenon with Elmo 1.0...great combo along with a 16-CL Xenon for that super bright white light.

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Robert Pitman
Junior
Posts: 24
From: Wales, UK
Registered: Mar 2007


 - posted April 19, 2007 05:32 PM      Profile for Robert Pitman   Email Robert Pitman   Send New Private Message       Edit/Delete Post 
Thanks Kevin,
I think you hit the nail on the head.
So there is pretty much nothing that can be/is worth doing really.

The motor sure does make more noise than the hum anyway.
Rob

Update
Fixed the lack of light on half power and reverse. Transformer tested fine and merrily chucked out 22 or 24 volts exactly as John mentioned. Turned out to be the microswitch nearest the main switch.
The whole thing was very easy to do and I actually surprised myself. Luckily the Elf is modular and everything came apart easily. Hardest part was putting the microswitches back in, very fiddly especially the 2 arms that throw the switches. I wrapped a rubber band around the whole thing first then located the screw holes, gave them a couple of turns and then cut the elastic.

I'm going to just ignore the transformer hum.
The play in the take up arm is not that bad since I put on a new belt.
The machine feels and operates like new.

Once again thanks to John and everyone for your help.
Rob

[ April 22, 2007, 09:10 AM: Message edited by: Robert Pitman ]

--------------------
Why do transformers hum?
Because they don't know the words.....

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