CP500 problem

[Frank Raia]

So the SK4 button is not working. In fact SK2 button works but the red light does not come on.
SK3 button works but the red light does not come on.
SK4 button does not work nor does the red light.

The button does not feel broken and clicks like all the rest.

I took the ribbon cable off both ends and reattached hoping maybe a contact was dirty from the main board to the front panel.

I reset the unit and it did not correct.

Everything else seems to work.

Any suggestions or other things to try?

[Frank Raia]

I guess i'm S.O.L on this one ! lol

[Tony Bandiera Jr]

Power the unit down, open the front panel.

Pull and reseat the main boards on the bottom, and do the same for all of the cards in the card cage. Be very careful with the two mainboards, DO NOT force them in. You will have to apply a slight upward pressure under the center of the boards as they sag a bit.

If that does not restore the key functions, then the board in the door itself is bad. You might be able to find replacements on fleabay.

All else fails, contact Moving Images Technology here in the US, they often have used CP-650s for sale at a reasonable price.

[Frank Raia]

Thank you Tony

[Tony Bandiera Jr]

You're welcome Frank.

Another possibility (if you can get it) might be to try reflashing the firmware but be aware it is risky and you may brick the processor. Be sure to back up your settings using dolby's setup software (which you will need to reflash firmware with anyway.)

[Alan Lyman]

I would try to activate the buttoms from the remote plug,and see what happens.I think if alright,the problem would lie in the frontpanel,if not,then the mainboard.If the latest,a cheap thing to try is to replace all the electrolythic capacitors on the mainbard.The cp500 has some years on now.

[Frank Raia]

Tony, I will have to see if my laptop has the port needed. Firmware is nerve racking!

Alan thank you for your suggestion. I found a main board on ebay and will give that a try. How do you activate the buttons from the remote plug? I did look on the web and I guess there was a remote (part #689). I cant find on on the web. Can I control the CP500 from a lap top?

[Ryan Gallagher]

Tony, I will have to see if my laptop has the port needed. Firmware is nerve racking!

Alan thank you for your suggestion. I found a main board on ebay and will give that a try. How do you activate the buttons from the remote plug? I did look on the web and I guess there was a remote (part #689). I cant find on on the web. Can I control the CP500 from a lap top?

The manual has a breakout of the remote/automation connection features... which should allow you to bypass your non-working buttons if nothing else is wrong. Serial control was a bit more of a headache, but possible, check out the thread below from way back in the archives. The Load500 software for backing up settings and doing firmware stuff was true RS232 to the serial port. But all the rest of the serial like control required sending RS485 hex commands to the the remote fader connection. The dolby doc describing the remote fader command list seems hard to find, but Ray Derrick's contributions to the thread should get you there:

https://www.film-tech.com/cgi-bin/ub...001344/p1.html

The CP500 remote control uses a non-duplex RS485-type connection, meaning it is single data line for both send (Tx) and return (Rx) data, plus a ground connection. The data format is conventional common RS232 9600/n/8/1. However to interface with an RS232 terminal it is necessary to connect the RS232 pin 2 to the CP500 data line and connect a small signal diode (such as a 1N914) between RS232 pin 3 (diode anode) and the CP500 data line (diode cathode).

He went on to list a bunch of command examples in hex.

[Ryan Gallagher]

In my searching I also found this "CP500 Reference Diagrams Manual". Fancy. I didn't see it in the warehouse manuals list, but film-tech is hosting it, as well as the CP500 manual.

It has some good extra information for wiring to either the automation or remote connections.

Manual
https://www.film-tech.com/warehouse/...DOLBYCP500.pdf

Reference Diagrams
https://www.film-tech.com/warehouse/...500REFDIAG.pdf

[Frank Raia]

Thank you very much Ryan!