K5synth

If the LCD flashes, it means that there's something getting to the data 
lines, but not correctly... Maybe cheesy logic, or signals that don't 
get to them. (Maybe a damaged PCB trace?)

The first chip where the wheel pulses go in is U9, a 74HC365 chip. Then, 
U12, a 74HC74, and finally, U7, an other 74HC365. I don'T know if it'S 
possible to simulate the wheel, but I'd change the three logic ICs 
first. I don't have my K5 and schematic in front of me, but I think that 
testing the logic is not really worth it. After all, it costs about 
$0.25 per chip, so changing them would be the easiest and cheapest 
solution.

When you remove chips in your K5, cut the pins with a cutter right next 
to the DIP plastic casing, remove the pins one by one and then use a 
desoldering pump to remove the remaining solder in every holes. It's 
long, and risky for the PCB, but it's the only way to remove a chip on 
these boards.

Antoine


bill bigrig a \ufffdcrit :
> Howdy,
>
>  ichecked the data wheel connections al the way down
> to the chassis cicuit board. Thay all conduct. All the
> butons work. I tried jumpering the pins on the data
> wheel contancts, but to no avail. I shot it with
> circuit cleaner, but nothing. I notice that the
> display blinks when turning in one diretion, but stays
> steady the opposite way. Is there a way to simulate
> the pulses from the data wheel? Either the wheel
> doesn't work, or there is a problem on the lower
> board. any ideas? Do I need a logic tester to test the
> data wheel? Also where are the +/_ buttons that the
> display says to press, or is it moving the data the
> way to selct plus/minus. What is the first chip on the
> board that the data wheel goes into and what should I
> expect at the pinouts?
> Thanx
> Rig
>
>
> --- bill bigrig <billbigrig@...> wrote:
>
>   
>> Howdy,
>>
>>  Assuming I get the wheel working,9the cursor
>> switches
>> do work), how do I com up with a source for the
>> original sounds to load with system exclusive?
>> Thanx.
>> Rig
>>
>> --- Antoine Desch\ufffdnes <antdes45@...> wrote:
>>
>>     
>>> bill bigrig a \ufffdcrit :
>>>       
>>>> Howdy,
>>>>
>>>>  You say to diconnect then reconnect the
>>>>         
>> battery?
>>     
>>> Yes, that's the only way to reset the RAM. I said
>>>       
>> a
>>     
>>> while ago to 
>>> disconnect and reconnect the battery to reset the
>>> synth, and I just said 
>>> to disconnect and reconnect the cables between
>>> MI-003 and the wheel.
>>>       
>>>> I forgot. The rest of your tips, I will try, and
>>>>         
>>> THANK
>>>       
>>>> YOU for this valuable info. i will do these
>>>>         
>> tests
>>     
>>> and
>>>       
>>>> get back to you. THANX AGAIN!!!!
>>>> Rig
>>>>
>>>>
>>>> --- Antoine Desch\ufffdnes <antdes45@...> wrote:
>>>>
>>>>   
>>>>         
>>>>> If the battery doesn't work, you'll just lose
>>>>>           
>>> your
>>>       
>>>>> sounds every times
>>>>> you start the synth. The ROM can't be damaged
>>>>>           
>>> from
>>>       
>>>>> normal use. I'd try
>>>>> to reseat(disconnect, connect) the cables
>>>>>           
>> related
>>     
>>> to
>>>       
>>>>> the switch and
>>>>> wheels if I was you.
>>>>>
>>>>> To put back sounds you'll need the wheel to
>>>>>           
>> work
>>     
>>> :
>>>       
>>>>> You have to go in
>>>>> the midi menu to enable SysEx receiving and
>>>>> transmission, which is
>>>>> sadly impossible for you right now.
>>>>>
>>>>> But if the buttons work and not the wheel, the
>>>>> interface should still
>>>>> work, unless you have an hardware problem
>>>>> somewhere...
>>>>>
>>>>> OK, I looked at the schematic(All the following
>>>>>           
>>> is
>>>       
>>>>> about the MI-003
>>>>> circuit board). The two wheel encoder signals
>>>>>           
>>> pass
>>>       
>>>>> through three 74HC
>>>>> logic ICs to end in the same data lines as the
>>>>> LCD(The CPU seems to
>>>>> use the same data port for both) If your LCD
>>>>>           
>>> works,
>>>       
>>>>> the problem is
>>>>> more likely to be situated with the logic(Two
>>>>> 74HC365 and a 74HC74) or
>>>>> the wheel encoder itself.
>>>>>
>>>>> The encoder signals pass through R10 and R8 to
>>>>>           
>> go
>>     
>>> in
>>>       
>>>>> U9, then U12 and
>>>>> U7. Maybe you could try to see if the signal
>>>>> actually gets to R8 and
>>>>> R10?
>>>>> In my case, I briefly get some pulses on R8 and
>>>>>           
>>> R10
>>>       
>>>>> while I turn the
>>>>> wheel.(The encoder uses pulse switches)
>>>>>
>>>>> And now, on the MI-008 board, the two bottom
>>>>>           
>> pins
>>     
>>>>> should feed 5v to
>>>>> the encoder, and the top ones just send pulses
>>>>>           
>>> when
>>>       
>>>>> it's turning.
>>>>>     
>>>>>           
>>>       
>>
>>  
>>
>>     
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>>     
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