View Full Version : Yamaha CX-830 remote volume problem


nazrin
08-20-2009, 11:53 AM
I have the CX-830 control amp and I can not make volume move with remote in one direction. I found if I flip the control wire on the volume knob board, the volume will not go up or flip around again and will not go down with remote. I think that shows the volume knob board with motor is ok, it must be the mother board that controls this board/motor. What can I do or look at to figure this out?

avionic
08-20-2009, 01:50 PM
I would say that on the remote, the volume "up/down buttons" contact pads, need to be cleaned with some IPA ( isopropyl alcohol )...:yes: They are always getting crap spilled on them and the pads get dirty frequently.

nazrin
08-20-2009, 02:02 PM
No, becasue I can swop the cables on the volume motor board and make it work one way or the other. That means the remote is ok and the motor and motor board is OK. And I can make other things work with this remote. Nothing wrong with both devices, It must be the mother board of the control amp.

avionic
08-20-2009, 02:16 PM
No, becasue I can swop the cables on the volume motor board and make it work one way or the other. That means the remote is ok and the motor and motor board is OK. And I can make other things work with this remote. Nothing wrong with both devices, It must be the mother board of the control amp.
No, becasue I can swop the cables on the volume motor board and make it work one way or the other. That means the remote is ok NOT!

When you swapped the wires which buttons on the remote are you pressing to make the volume change? Both up and down or just up or down?
Known ..IR detector works ,pulse decoder works, motor and controller works,power supplys OK ...

nazrin
08-20-2009, 03:24 PM
I don't think your understanding or I'm not explaining well, inside the CX830 amp is a PCB & motor that drives the volume knob. there are two cables, one for up volume and one for down volume. my CX830 will volume up but not down, when I swap these cable around the volume will not go up but will go down, that tells me the Volume PCB board and motor is ok, and I know the remote is ok becasue I volume other devices with it OK, That said, the only thing is left is the mother PCB board that these cable are coming from.

avionic
08-20-2009, 04:02 PM
my CX830 will volume up but not down, when I swap these cable around the volume will not go up but will go down, What buttons on the remote are you pressing to test the preamp? Volume up or volume down.or both?? If its not the remote..It is the pulse decoding chip in the controling circuit or a driver transistor/chip.

avionic
08-20-2009, 04:11 PM
If the 830 is similar to the 1000 its a single microchip that controls all remote functions.

nazrin
08-21-2009, 07:27 AM
What buttons on the remote are you pressing to test the preamp? Volume up or volume down.or both?? If its not the remote..It is the pulse decoding chip in the controling circuit or a driver transistor/chip.


Well, that sounds like something on the mother (main)PCB, we can rule out the remote, it works like new. I feel I can rule out the volume knob PCB with motor,

To sum this volume PCB board up, there are three sets of wires, two match and one odd, the odd one is a two wire cable which is DC power to the board, the two cables that match are the up volume and down volume control which have three wires each, the connectors are interchangable. If it only goes up one way, then swap the connectore around then only goes down one way, I feel this PCB and motor is working OK, must the the main board that is sending the singles, which holds yes IR circuits and other things.

What can I check on this main board?

avionic
08-21-2009, 11:25 AM
Do you have a schematic and a scope..

nazrin
08-21-2009, 02:05 PM
Do you have a schematic and a scope..

no schmt. and no scope

avionic
08-21-2009, 02:11 PM
no schmt. and no scope

That suxs..Need to see if the decoder is recieving the pulse train from the detector.Is this a universal remote control or the OEM yamaha 830 remote?If OEM do the rest of the functions on the remote respond correctly?

nazrin
08-21-2009, 02:19 PM
this is a universal, I can use it on other devices and I have tried many other remotes and always the volume only move one direction, I have another Yamaha device and the volume works normally with this remote, that is way I ruled out the remote, and from swapping the cables the motor PCB also.

avionic
08-21-2009, 02:38 PM
Well..Without the proper test equipment or tech data.Your shooting in the dark.If you can figure out which IC chip is responsible for decoding I guess you could "shotgun"it.If you can find a replacement chip.Or send it to a tech.I know a couple yamaha techs.:D Or do without the remote.Its probably a single microchip that controls all of the remote functions. mike@vintageaudiomanuals.com
Mike Thomason can probably hook you up with a manual.

nazrin
08-21-2009, 02:52 PM
Well knowing to look for a chip, may be worth openning up again and scratching my head. I was hoping for some easy magic. Thanks

Jon_Logan
08-21-2009, 03:11 PM
The motor drive is likely not embedded in the uController IC. That is good. Look for an IC that looks a little hefty (because it's a power IC). It might begin with the letters BAxxxx.

nazrin
08-21-2009, 03:12 PM
thanks, will look

avionic
08-21-2009, 03:20 PM
The motor drive is likely not embedded in the uController IC. That is good. Look for an IC that looks a little hefty (because it's a power IC). It might begin with the letters BAxxxx.

Also look over the printed circuit board that the motor's connectors are on..Might just be a bad solder connection on the connector pins.

Jon_Logan
08-21-2009, 03:24 PM
I may be way off base with the description and numbering of that IC (if it exists). You described the wires that you flipped to make the volume control motor turn the opposite direction.... .....try to follow those back to an IC (or less likely transistors). The driver for the motor won't be separated from the motor by too many components, if any.

It is sounding like an H-bridge driver issue. An H-bridge get's you reverse polarity with a minimum power supply voltage. Think of the motor hanging in the middle of an H, where the vertical lines of the H are connected to ground (at the bottom) and some voltage (at the top).

It's sounding like one side of the H-bridge (driver IC) is open.

nazrin
08-24-2009, 07:26 AM
The motor drive is likely not embedded in the uController IC. That is good. Look for an IC that looks a little hefty (because it's a power IC). It might begin with the letters BAxxxx.

I looked over the main PCB and found a chip, it is set up on the board like a resister pack, but is black like a chip the numbers are:

PCB # IC10
chip# BA6229
other small # 012 358

It does look like it drives something, becasue it has a thin heat sink fin sticking out the top of it.

Also, I set an emial to Mike and he said he has NO circuit print for this CX-830

What is this BA6229??

nazrin
08-24-2009, 08:00 AM
Well, I see this is the motor drive, what should I check with Ohm meter?

nazrin
08-25-2009, 07:51 AM
I may be way off base with the description and numbering of that IC (if it exists). You described the wires that you flipped to make the volume control motor turn the opposite direction.... .....try to follow those back to an IC (or less likely transistors). The driver for the motor won't be separated from the motor by too many components, if any.

It is sounding like an H-bridge driver issue. An H-bridge get's you reverse polarity with a minimum power supply voltage. Think of the motor hanging in the middle of an H, where the vertical lines of the H are connected to ground (at the bottom) and some voltage (at the top).

It's sounding like one side of the H-bridge (driver IC) is open.


Any idea on what to check with the meter on this IC10?

Jon_Logan
08-25-2009, 09:10 AM
Hi Naz,


Here's the datasheet. http://pdf1.alldatasheet.com/datasheet-pdf/view/36071/ROHM/BA6229.html

It's made by Rohm, and it is a motor drive IC. If it's the only motor in the set, it looks like you found the right IC.

Measure "IN1" and "IN2". You can measure them each to ground, or you can put your DC voltmeter across "IN1" and "IN2". The datasheet shows a typical input voltage to the "INx" pins as 2 volts. I think it's sufficient that you could measure each "IN" pin when the remote control's volume up/down buttons are pushed. You should see equal but opposite (complementary) action for the volume directions.

As a strategy, it's best to be worried about the part that has the toughest job to do. In this case, it's the motor driver IC and not the uProcessor. It always could be the uProcessor, but my money is on the motor drive IC.

You might have to get this part from Yamaha. It looks like B&D still has them. http://www.bdent.com/search/part.jsp?partnum=BA6229

nazrin
08-25-2009, 12:02 PM
So, the IN1&2 are the 2 volt input indirectly from the remote volume button?

ie: volume up 2 volt on one pin, volume down 2 volts on other pin? SO, that said if I'm seeing these 2 volt signels then we point to IC10 if one signel is missing we point to the processor?

Jon_Logan
08-25-2009, 12:15 PM
If IC10 is the BA6229, then yes... you should see ~2 volts appearing on either pin5 (IN1) or pin6 (IN2) as you press vol up/down on the remote.

If the voltages don't appear on IC10, it might be the uProcessor but not 100%. It could be that a bad motor driver is trashed all the way to the input and pulling a voltage up or down.