Film-Tech Forum ARCHIVE: Cinemeccanica V5 Sound Reader help

This is topic Cinemeccanica V5 Sound Reader help in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Rose Oldershaw (Member # 9727) on 07-25-2017, 08:43 AM:

Hello,

I'm looking for some help in trying to get the D08140 Dolby Analogue sound reader operational in the Vic5 that I saved from being scrapped. I have a CP55 and a USL JSD80 to run with it but my problem at the moment is powering it.

I have all the original power supplies from the pedestal base but unfortunately not the base itself as that was stripped and went missing over the years.

I have seen referenced before the BAS 402 power supply seen on this thread
http://www.film-tech.com/ubb/f1/t011601.html

However my confusion comes from the exactly supply voltage required, the BAS402 outputs around 2.5v at max yet while looking at the texas instruments ICs on the board datasheets they need at least 7v to operate.

Seeing previous posts I did try to use a 12v supply but with no joy. I'm also assuming that (because I have never run these machines) that the red LED is visible light to begin with.

I've attached a couple of photos of my unit and if I'm missing anything obvious please let me know.

Thanks,
Rose

Posted by Allan Lyman (Member # 9449) on 07-26-2017, 03:09 AM:

Hi

Cinemcc,just putted 24v on the + and -,leaving the gnd unconected.BUT the supply must only then be used for the soundhead,nothing else,as putting the - to gnd,will kill the sound.Also you can supply it with +/-15v,the the 24v is easier.I use it myself in my homecinema.

Posted by Rose Oldershaw (Member # 9727) on 07-27-2017, 05:21 AM:

Thank you Allan, I have ordered a 24v supply to test with.

Thanks,
Rose

Posted by Marco Giustini (Member # 4544) on 07-27-2017, 05:48 PM:

You may want to use linear (not switching) power supplies when it comes to analogue sound.

Posted by Mark Gulbrandsen (Member # 72) on 07-27-2017, 06:24 PM:

Kelmar used switching supplies on all their red readers. The outputs were just well filtered.

Mark

Posted by Allan Lyman (Member # 9449) on 07-28-2017, 05:27 AM:

Both I and Cinemecc. used analog PSU´s,but Kinoton used switching.

Posted by Marco Giustini (Member # 4544) on 07-29-2017, 12:27 PM:

Either a well filtered switching PSU or a linear one. To be on the safe side I'd go with a linear for this application, unless it's coming from the manufacturer.

Posted by Jonathan Wood (Member # 4614) on 07-30-2017, 09:35 AM:

Hi Rose
Those grey PSU's where just for the LEDs not the pre amp board. The preamp board need 12-24vdc but make sure you connect it correctly (plus to plus , minus to minus) of you will fry the board. There should be a couple of black wires dangling from the Leds - you can use your grey PSU's to power these. I ended urp getting a Kelmar dual supply which powered both the analogu and digital LEDs and provided 24vdc to the analogue pre amp board . The digital board gets power from the CP. Looks like your board is out of situ which means you will need aligning . Good luck ! jon

Posted by Garry Knapp (Member # 9697) on 08-19-2017, 06:43 AM:

Hi all...
been following this thread with keen interest. Just found out I have been under-powering my reader. My new supply puts out 27v.
Too high...unless there's some room or I put a resistor inline?
Or I hunt down another source for 24v. I hear there's a point on the back of the CP650 to get the 24v?

Posted by Allan Lyman (Member # 9449) on 08-21-2017, 03:44 AM:

you should not go highr than 24v,there are resistors on the bord,that gets hot.
yes the CP650 can provide +/-15v on the optical input plug.
see manual in warehouse here,for pins.

alan

Posted by Rose Oldershaw (Member # 9727) on 08-25-2017, 06:35 PM:

Hi all,

Thank you for all the comments, I haven't had a lot of time to play around with it lately.

It turns out I do have the original 24v supply that was used with the preamps in this projector. It's quite a bulky linear supply. However I cannot figure out where the Analogic supply is supposed to connect to for the LEDs I don't have any leads coming from the LED as Jonathan has suggested.

But anyway hopefully I'll get some more time to investigate it soon.

Thanks,
Rose

Posted by Jonathan Wood (Member # 4614) on 09-04-2017, 03:25 AM:

Hi Rose

Each LED should have a black and a red wire coming from them, they sometimes get wound up and tucked away somewhere but if you've had a good check then it looks like they were (unhelpfully) snipped! If you replace them make sure you know the polarity before you re-connect . I would have thought that if you trace back into the sound head as far as you can, you should see some evidence of the cables ? Good luck , Jon