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Author
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Topic: AUDIO CHANNEL MISSING KINOTON BASE READER
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Ian Griggs
Film Handler
Posts: 30
From: Lithgow, NSW / Australia
Registered: Jul 2016
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posted 11-02-2017 08:38 PM
Hi all, apologies if this topic has been raised before. My Kinoton FP20 has the late Kinoton Digital Base Reader installed. I only have the optical track red LED connected up, but I am missing the RH audio channel. I have traced right through as far as the little pre amp circuit board, and all is fine. Therefor I have narrowed the fault down to misalignment of the LED, or the focussing lens assembly. Both of these of course are not supposed to be touched by "screwdriver experts", but one has obviously got out of kilter. The other possibility is that the RH photo cell has failed, but this is unlikely. I have the 30 page manual for this reader, which goes into all kinds of tests, but as I don't have an oscilloscope, these are beyond me, and I would need to rely on my ear. If anyone has had a similar issue, or could point me in the right direction, I'd be grateful. Before anyone asks, I should point out that there is no RH channel, with either a film running, or with the trusted "screwdriver in the beam" test!
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Leo Enticknap
Film God
![](http://www.film-tech.com/ubbmembers/534a.jpg)
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 11-02-2017 10:32 PM
Do you have a buzz track test film? If so, thread it and listen. The buzz is recorded outside the area that the cell should be scanning, so if you can hear the buzz, the alignment is off. Adjust the lateral alignment until the buzz goes silent, and you should be roughly right to the extent that you'll be able to hear something on that channel.
However, realigning the A-chain (photocell) accurately enough for Dolby SVA to work with acceptable channel separation really needs an oscilloscope, several test films and a lot of patience. Alignment, focus and slit azimuth must all be adjusted with the right test film loop running and observing the output on your 'scope. But with just a buzz track, you should be able to get it back to the point at which mono optical is just about OK.
One wacky thought: are you absolutely sure that the problem is in the A-chain? Sorry if this sounds too much like the bleedin' obvious, but I take it that you've ruled out the B-chain by playing another source (not optical film sound) into the audio processor, and checking that the right channel is OK?
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Leo Enticknap
Film God
![](http://www.film-tech.com/ubbmembers/534a.jpg)
Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000
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posted 11-02-2017 10:52 PM
If you have low audio on the RH channel, it's definitely an A-chain problem. If that channel was dead (either in the A or B chain), then any signal cross-talking into it from the L would not be audible: the cell wouldn't be generating any signal.
The only other thing I'm wondering about is a fault in the preamp board whereby it isn't amplifying the signal from that channel as much as it should. Kinoton readers are known to be pretty stable: the alignment doesn't slip, as a general rule (unlike the ones on Cinemeccanica Vic 5s, which need their A-chains doing several times a year to avoid crosstalk on SVA becoming horrible). Shortly before I left my last job, I checked out the A-chain on the two Kinoton Dolby SVA/Dolby Digital basement readers on a pair of Norelcos. The lateral alignment and slit azimuth on both were perfect - didn't need to be touched at all - and it was 12 years since they were installed and set up. We did need to replace the LEDs, though: they'd deteriorated to the point at which the CP650 couldn't boost the signal to within range for analog, or an acceptable video level for digital. I don't think that this is your problem, however, because if it was, it would affect both channels equally, not just the right.
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