Film-Tech Forum ARCHIVE: Smart SR300 dead surround channel

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Posted by Dan Lyons (Member # 1454) on 09-11-2004, 05:10 PM:

Damn thing crapped out on me last week. [fu]

When running a "sound test" reel, i noticed that i was no longer getting anything from the surrounds. My solar cell is perfectly aligned; definately a problem with the the Smart.

When I turn up the pot for the surrounds to full while running pink noise, i get some sound, but not much; but lots of cracks, pops, and hisses. Occasionally the pink noise will cut in at full blast, but then cut out again.

So, what part in my processor has died? Possible to fix, or should i just run with no surrounds until I get a better processor and throw the Smart in the trash heap. I know nothing about the inside of electric things, so the last option is most likely.

danny [Mad]

Posted by Steve Kraus (Member # 476) on 09-11-2004, 06:39 PM:

I suppose it could just be a dirty adjustment pot in which case it might be cured by running it up and down a lot or possibly with a squirt of contact cleaner. If that's all it is then it is probably an inexpensive replacement but I really can't see why you'd want to make any effort to keep that unit in service when you can get a good used CP50 or pretty much anything else that would do the job better.

Or maybe that should just be "would do the job" since there is so much lacking on that unit that the point can be reasonably made that the job isn't being done even when it works.

Posted by Don Sneed (Member # 955) on 09-11-2004, 11:19 PM:

Yes I would expect a dirty pot or dirty master volume volume control, try using the Cat.151B test film to check & adjust the surrounds

Posted by Dan Lyons (Member # 1454) on 09-12-2004, 12:23 AM:

THe master volume is fine. All other channels are behaving properly. After i cleaned the surround pot, it stopped working completely.

Posted by Steve Kraus (Member # 476) on 09-12-2004, 01:30 AM:

That kind of infers that it's the pot.

Posted by Stan Gunn (Member # 554) on 09-13-2004, 06:31 AM:

sounds to me that it is working fine,
playing a test film and hearing noises in the surround out may be just a test film with no surround content.
Try shorting out one channel and see if the sur comes in,or use the card over halve the cell trick.

Stan

Posted by Oscar Neundorfer (Member # 458) on 09-13-2004, 07:16 AM:

Dan,

You said this:"When running a "sound test" reel,..."

Exactly what type of test reel were you running? At one point you said that occasionally the pink noise will cut in at full blast. Are you running the pink noise side of the Cat69 test film? Did the blasts of pink noise occur at the splice point in the loop? Pink noise from CAT 69 is in phase and should not normally produce much sound from the surround channel if all is aligned properly.

If you have CAT 151 choo-choo test film, run that. You should get alternating front and surround bursts of pink noise.

Better still run a regular print known to have good surrounds. Is it totally dead on surrounds?

How about non-sync music. Any surrounds there? If so, then at least we know that the output stage, interconnects to the rear panel board, external wiring, amps and speakers are OK.

SR300's had some problems with connections from the main board to the rear panel board. These would sometimes get intermittent and cause loss of channels.

Bottom line is that if there is a problem, it it would be better to upgrade to another processor which would give you SR playback capability and overall better quality than the SR300 could ever do.

Posted by Dan Lyons (Member # 1454) on 09-13-2004, 01:44 PM:

quote: Oscar Neundorfer
SR300's had some problems with connections from the main board to the rear panel board. These would sometimes get intermittent and cause loss of channels

Thanks for all the info Oscar. [thumbsup]

I've tried all the things you suggested, and now I'm sure the problem is either the pot, or the above, or a combination of the two.
For now, my LCR are working fine, i'll just run with that.

I am thinking of upgrading to a CP-50, so if anyone has one in good working order for sale, drop me an email.

Danny

[ 09-13-2004, 04:35 PM: Message edited by: Dan Lyons ]

Posted by Daryl C. W. O'Shea (Member # 1303) on 09-13-2004, 01:47 PM:

If Mark keeps using those dashes from hell I'll have a spare loonie I'll trade you for the SR300.

Posted by Dan Lyons (Member # 1454) on 09-13-2004, 01:56 PM:

You'll trade what? errr.. hmm...

btw.. I just went to the screening room to mess with the processor again. Played some non-sync, guess what, the surrounds work today, and the pot is fine. So it's definately the bad connection Oscar spoke of. Of course, the surrounds will keep working until I have someone over to watch a film, then they will crap out again, that's the nature of the SR300. [evil]

danny