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BE Cart Machine Problem

R

Robert Bass

OK gang, play along with me here for a moment.

I have a Broadcast Electronics Series 3000 stereo Record / Reproduce cart machine. The deck isn’t being used for critical applications; it’s more of just for hobby use.

To my unfortunate disadvantage, I don’t have an alignment tape for the deck. As far as I can tell, from playing a cart recorded on what I presume was a properly aligned machine, the playback on my BE machine is very good. So I am assuming the playback head is aligned properly.

Here’s the problem; when I record tones on carts to see how well it works, the 1 kHz and 10 kHz tones are printing to the tape. But when I switch to a 50 Hz low frequency tone, I get nothing. Playing this same recording in another reproduce unit, I see the 1 kHz and 10 kHz tones on the meters, but nothing for the 50 Hz tone.

I have tried playing around with the record EQ adjustments, to no avail. So I’m thinking either a record head alignment issue, incorrect bias or some other technical problem with the deck itself. The heads themselves look very nice, so I don’t think it’s a worn head problem.

Any thoughts?

Thanks,

R
 
What does it sound like with a music cart?

It is possible that the playback card is dying. This does not sound like a head problem, but there may be issues with the playback card. Do you HEAR the 50Hz tone (forget the meters for a moment)
 
wgliradio said:
Do you HEAR the 50Hz tone (forget the meters for a moment)
Click to expand...

wgliradio,

Thanks for the suggestion!

I tried it, and I can barely hear the 50 Hz tone when playing back the tape / monitoring on repro during recording. I also tried 100 Hz, and the results are similar. 1 kHz and 10 kHz tones are still coming through loud and clear.

Any ideas?

R
 
Idea? Yeah, the playback system has no low end response. Also, >if< the thing has a low frequency tweak like some of them, be sure it isn't just turned all the way down. I'm with whatsisname, I'd shotgun all the caps in the thing for starts.
 
Hmmm.... just discovered something. The low end is present in the headphone jack, it's just missing from the line output. Weird ???

R
 
Do you have a schematic for it?

Headphone feed will be BEFORE the drive to the balanced line amps, so there's something rolling off the LF response of those.

My pick is it's in that area, and more than likely, as already mentioned - it needs recapping.
 
Studio1 said:
Do you have a schematic for it?

Headphone feed will be BEFORE the drive to the balanced line amps, so there's something rolling off the LF response of those.

My pick is it's in that area, and more than likely, as already mentioned - it needs recapping.
Click to expand...

Yeah I have a service manual with schem's. I'll try recapping, and see what happens.

Thanks all!

R
 
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