CP650 hearing impared output problem

[Josh Jones]

Here's one for the brain trust...
I have a CP650 that at one time had a cat. 791 card in it, but has been uninstalled, and all jumpers verified to be in the stock position. The hearing impaired output seems to only have stereo difference information, i.e. surround track info present only, no dialog. Is there a setting or jumper some place that would cause this? I am intending to use the output as a booth monitor, and not having the center channel is a big problem.

Thanks all,

JJ

[Steve Guttag]

I don't recall there being any jumpers for the CP650. If you have a CAT 790/791/794/778 installed, the unit configures itself appropriately. If you haven't already, I would run a firmware update to ensure that all of the remaining boards configure themselves in their present state. The HI output should always be center-weighted L/C/R mix and analog. For you to be getting a difference mix implies that there may be a failed component or cold solder joint in the path (kind of like a floating neutral in electric circuits).

[Marco Giustini]

I'd start with a channel ID to understand what actually goes into the HI output.

[Ryan Gallagher]

Was it typical to use HI for booth monitoring in 650 only booths? I feel like the norm would have been a more complete monitoring device with access to all channels?

We get ours off an AP20 that is after the 650 in the signal path, but I have not looked at how one would do that without the extra device.

But one would still want to troubleshoot HI for other reasons.

[Josh Jones]

I don't have the rack space for a booth monitor at this time. Also, I want to make use of the balanced outputs of the processor, and the monitor I have is unbalanced. In this case, the HI output is good enough to hear what's going on in the room. I have verified that the symptom persists in various sources and formats, so it must be something in the processor. The block diagram in the book doesn't show how the signal is derived, or on what card.

JJ

[Tony Bandiera Jr]

IIRC the HI and bypass audio (all analog) circuitry is on the main board. (Cat 772 Analog I/O and bypass) Close examination of the main board should lead you to the op amps used for the HI. Wish I still had my CP650 I could find them...the Late Sam Chavez told me the locations when my personal CP650 had some issues....

[Josh Jones]

I found the problem. When I disabled the digital crossover card, I apparently left the jumpers in the wrong position. Somehow that affects hearing impared output so I was getting either left or right only. Everything worked fine otherwise. Now that the jumpers are correct, all is working, including my improvised booth monitor.

Thanks all!