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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » AUDIO CHANNEL MISSING KINOTON BASE READER

   
Author Topic: AUDIO CHANNEL MISSING KINOTON BASE READER
Ian Griggs
Film Handler

Posts: 29
From: Lithgow, NSW / Australia
Registered: Jul 2016


 - posted 11-02-2017 08:38 PM      Profile for Ian Griggs   Email Ian Griggs   Send New Private Message       Edit/Delete Post 
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

Posts: 6840
From: Loma Linda, CA
Registered: Jul 2000


 - posted 11-02-2017 10:32 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
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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Ian Griggs
Film Handler

Posts: 29
From: Lithgow, NSW / Australia
Registered: Jul 2016


 - posted 11-02-2017 10:40 PM      Profile for Ian Griggs   Email Ian Griggs   Send New Private Message       Edit/Delete Post 
Hi Leo. Thank you for that. I do have several loops - not sure if there is a buzz track one amongst them. The loop I am testing with at the moment is a simple excerpt from an ad or something - just pictures with about 10 seconds of optical track. I have moved the focus barrel in and out a few turns, and it was already set at the best position for HF.
With regards to following the chains, I have both channels perfectly all the way from the little pre amp circuit board to the speakers. So the problem is before the board. From what you are saying, the lateral adjustment may have come adrift, but I was reluctant to touch that, as all the red paint dots have never been moved. PS If it helps, I DO have a VERY low audio on the RH channel, but this may simply be cross talk.

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Leo Enticknap
Film God

Posts: 6840
From: Loma Linda, CA
Registered: Jul 2000


 - posted 11-02-2017 10:52 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
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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Ian Griggs
Film Handler

Posts: 29
From: Lithgow, NSW / Australia
Registered: Jul 2016


 - posted 11-03-2017 12:50 AM      Profile for Ian Griggs   Email Ian Griggs   Send New Private Message       Edit/Delete Post 
Hello again Leo.
Well,I have isolated the problem now.
It is with the actual photo cells themselves!
The LH is OK but the fine connection between the RH cell and the solder point on the board has failed. This type of repair, being so fine, and special type of solder, I fear is beyond me.
To make matters worse, the one on the good channel is intermittently loose now too!
I think the only way forward here is for me to find a replacement analog board. Won't be easy, but this board is less than 20 years old (2000), so surely there are spares (somewhere). Fingers crossed. Thanks for your help.

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Leo Enticknap
Film God

Posts: 6840
From: Loma Linda, CA
Registered: Jul 2000


 - posted 11-03-2017 05:51 PM      Profile for Leo Enticknap   Author's Homepage   Email Leo Enticknap   Send New Private Message       Edit/Delete Post 
Yeah - the components on that board are fiendishly tiny. I still have nightmares about threading the wires from those LEDs through the tiny holes in the shafts, conscious that one slip of the finger or pushing too hard could FUBAR a $300 part.

Good luck.

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Sam D. Chavez
Film God

Posts: 2053
From: Martinez, CA USA
Registered: Aug 2003


 - posted 11-03-2017 07:19 PM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
I have raw solar cells used in the analog basement readers. You can unsolder the old one and solder in a new one fairly easily. You may need to adjust azimuth after though. And it won't cost anywhere close to $300 even with postage. I have genuine Dolby LEDs as well while you are at it.

Feel free to contact me if you can't source parts closer to home.

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Ian Griggs
Film Handler

Posts: 29
From: Lithgow, NSW / Australia
Registered: Jul 2016


 - posted 11-03-2017 07:44 PM      Profile for Ian Griggs   Email Ian Griggs   Send New Private Message       Edit/Delete Post 
Hi Sam - thank you for that. Since I last posted, my memory came good and I found a box of four little Siemens cells with wires attached! Forgot I had them. So now I'm about to do some microsurgery, and install one (or two in series) for the faulty channel. Bit tricky but that's what we do, isn't it?! Stay posted.
However, if all else fails, Sam are you saying you have those narrow cells in stock? Do they have wires attached (pos & neg)? Is it a difficult job to do? (See pic) You can email me direct if you like. iancgriggs@ozemail.com.au
 -

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Sam D. Chavez
Film God

Posts: 2053
From: Martinez, CA USA
Registered: Aug 2003


 - posted 11-04-2017 12:57 AM      Profile for Sam D. Chavez   Author's Homepage     Send New Private Message       Edit/Delete Post 
Ian,

I am assuming you have bare mono cells you want to put these in place or on top of the can with solar cell.. Too many issues to mention. I do have new cells in a round can exactly as shown.

You would need to de-solder the existing cell. It has solid wire leads out of the back of the can. I would find a friend who knows how to do this de-soldering.

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Ian Griggs
Film Handler

Posts: 29
From: Lithgow, NSW / Australia
Registered: Jul 2016


 - posted 11-04-2017 04:55 AM      Profile for Ian Griggs   Email Ian Griggs   Send New Private Message       Edit/Delete Post 
Thank you again Sam.
I have desoldered the three hard wires and removed this can, in order to install two of the little Siemens cells, however I believe the board is faulty as well. I did notice what appear to be dry joints on one end where the resistors are, and I reflowed them but I have a loud hash noise on the left channel. This is nothing to do with the cells set up. Just more things sent to try us. I think I should look for a whole new complete PC board, but I am willing to put in one of you cans with cells, if you'd like to email me some details. Many thanks!

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Randy Stankey
Film God

Posts: 6392
From: Erie, Pennsylvania
Registered: Jun 99


 - posted 11-04-2017 09:05 AM      Profile for Randy Stankey   Email Randy Stankey   Send New Private Message       Edit/Delete Post 
Just a note: Don't use lead-free solder on that board.

You need to use a 63/37 (tin/lead) solder with either water-washable or no-clean flux.

You can tell just by looking that the solder on that board is not lead-free. Most manufacturers use a eutectic (63/37) solder.

If you use lead-free or any other type of solder, it might look sound and it will work just fine out of the gate but, over time, mixed solder connections will eventually degrade. The tin in the solder will form dendrites (a.k.a. "tin whiskers") and the connections will physically break apart.

Back when these projectors were being made this wasn't such a concern. Lead-free solder probably wasn't even an issue.

Now that it is difficult or impossible to get replacement parts, I suggest you take every step to keep your projector working as well as it can, as long as it can.

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