Cvp 105 Midi Out Problem ..pls Help

[pempek40]

My CVP 105 MIDI OUT is not functioning. Midi In is working fine. It used to be working before. I have tried to use at different PC, but got the same problem.
The connection is through Serial Cable. (Circiular-8 to DB 9)

Having looked at the input assembly at inside CVP there are 2 ICs SN75C1168 (IC3) and SN74HCU04 (IC1).
Since it is too risky to trial and error. Please help for anybody who have experience or SCHEMATIC DIAGRAM.
Which component should I replace?

Waiting for your advice...........

THanks in advance


Jony

[Midi Magic]

Hi

Have you:

swapped over the midi leads?

tried the midi OUT from the cvp into another keyboard?

checked the program's midi settings are still set up correctly

checked that the program still points to the CBX driver

have YOU turned midi transmit OFF

There are still, many more things you need to check, before you go poking around inside the cvp.


FYI
The SN75C1168 is a Dual Differential Drivers And Receivers
and the SN74HCU04 is a 6x Hex Invereter

[pempek40]

Hi Midi Magic,

1.Thanks for the reply.

2.I will try as your suggestion, before doing at inside CVP (too risky)

3.I have a plan to make the loop configuration at the DB9 for testing and then try to run the TEST MODE at CVP. Any suggestion the pin loops assignment?

4.As for The SN75C1168 (Dual Differential Drivers And Receivers)
and the SN74HCU04 (6x Hex Invereter), which IC resposible for outputting MIDI OUT.
Please advise.

Waiting...............

Many Thanks

[Midi Magic]

Hi


Can you confirm, are using "Midi" leads into the Joystick port on the PC or are you using the "Serial" port to "Host"

As the plugs and pins are different.

[pempek40]

Hi,

-I am using 'Serial' port to 'Host'

-I already made test loop connection at circular-8 (at connector 'To Host' at CVP) pin1 to pin 2, pin 3 to pin 5,and pin 6 to pin 8.And run the test mode at CVP. The result is 'No Good'

-I thing the TX- pin-3 ('To Host' connector at CVP) is not working.
Playing Midi from from PC to CVP is working but
Playing CVP keyboard is not recognized by any MIDI PC softwares (it used to be working before)

-Probably among the CVP1xx series or CVP2xx series there are similarity of 'To Host' circuit Diagram.
There are 2 ICs in the PCB ...SN75C1168 and 74HCU04

Please advise......

[pempek40]

Hi,

-I am using 'Serial' port to 'Host'

-I already made test loop connection at circular-8 (at connector 'To Host' at CVP) pin1 to pin 2, pin 3 to pin 5,and pin 6 to pin 8.And run the test mode at CVP. The result is 'No Good'

-I thing the TX- pin-3 ('To Host' connector at CVP) is not working.
Playing Midi from from PC to CVP is working but
Playing CVP keyboard is not recognized by any MIDI PC softwares (it used to be working before)

-Probably among the CVP1xx series or CVP2xx series there are similarity of 'To Host' circuit Diagram.
There are 2 ICs in the PCB ...SN75C1168 and 74HCU04

Please advise......

[Midi Magic]

Hi pempek40

I have been looking for a shematic for a "To Host" connection but so far have failed.
You say you have looped back the lead by joining the pins but have you done it at the back of the CVP? At least that would prove the lead.

I did answer but it must have been on another post. Did you put 2 post up?

[pempek40]

-Thanks Midi Magic for your answer (that was waited...)
-I posted only in here.
-I make the loop back for diagnostic at CVP back panel (Circular 8 connector)
-Do you have schematic diagram of your cvp209? Any idea (similarity with cvp105) of 'to host' circuit?

Br.

[Midi Magic]

Hi

No sorry, as yet I have not been able to get any diagrams for any keyboards with a To Host socket. I am sure someone on the group must have one. Maybe they could scan just that section with the chips on for you.

If you have done all you can at your end, with loop backs, resets and checked the Host switch, then the only thing left is to ring Yamaha Tech support.

Do the Midi sockets still work? Maybe you could use them, via Serial - Midi or USB - Midi.

Meen while I will keep an eye out for any diagrams.

Good Luck

[pempek40]

Many thanks Midimagic for your info.

Br.

[Midi Magic]

Hi

How are you doing. I still have not found a diagram for the 105 but have found one for a CLP piano. This has a "Host" and I would think it would be the same.

First of all you can forget about the 74HC04. This is a 6 x Hex inverter of which only 1 inverter is used and this is used to send a 1 Mhz clock pulse to the Mac on pin 1.

The circuit I have uses a MC34051 which is a Dual EIA-422/423 Transceiver.

Have you checked for midi out at the Midi OUT socket? This can be easly checked by placing a LED & resister across pins 4 & 5. You will need to get the LED around the right way.

I have built a little tester out of a 5 pin din plug you can find one at this site. You don't need the Diode, well I didn't use one.

http://www.hut.fi/Misc/Electronics/circuits/miditest.html


Looking again at the pins of the Host socket you do not need pins 6 & 7 as these are only for the MAC.
Did you connect pins 4 & 8 together when you did your loop back.

Pins 1 & 2 are looped back to the PC with in the CVP so you can forget about then also.

Pin 7 has +5V on it so stay clear of that, just in case you short it out.

Again you could try a LED & resister on pin 3 to Earth play some notes and see if it flickers.

My first thoughts would be to check the "To Host" switch making sure it feels ok when you switch it. Make sure it is in the right setting PC2

[Midi Magic]

Hi

My other Midi Tester is made by Studiomaster or I should say was made by them. It is a MA36 and cost me £32 and is worth it's weight in gold.

I did try to get another one, just in case, but they have stopped making them. :confused: :confused: :confused: :mad: :mad: :mad:

[pempek40]

1.I double checked the switch is at PC2

2.I will do with the LED make sure that the main board of CVP produces the midi signal......and the only problem is the 'to host' port problem


3.You are are right Midi magic . It is the pin 3 prpblem. Pin 3 is Tx- that output to PC. I just checked this pin3, based on your info. It goes to Dual EIA-422/423 Transceiver (CVP105 uses 75C1168).I can forget the 74HC04. It is difficult to find 75c1168 so finally I called Yamaha Service Center . They have stock for the part. Will go to Yamaha......and inform you later.

Again...thanks a lot.

[Midi Magic]

Hi

Have you checked for midi out at the Midi OUT socket? This can be easly checked by placing a LED & resister across pins 4 & 5. You will need to get the LED around the right way.


I would check this first. If there is nothing here then there is NO midi from the cvp. MAKE sure you put the switch back to MIDI for this test.

Let me know

You don't say where you are from.

[pempek40]

*I had the LED at home but can't find it. But will try with this later. As it is very good and simple way to test MIDI out.

*It is said at datasheet that The 75C1168 has similar function with MC34051 you mentioned. Based on all your info ............brave enaough for me to replace the 75C1168. I cut all the pins of suspected IC (avoiding damage of PCB) and replaced it with new one....and it is working.

The problem has been solved. My Midi is back

Midi Magic...... I appreciate of all your attention and info.

MIDI IS MAGIC