Re: K5M - need IC26 EPROM file [4 Attachments]

Everyone,

I fixed the K5m!

I replaced IC15 (Toshiba TA8505P, reset controller, datasheet attached) and
now it works fine. However, I had to replace it with a similar IC since the
TA8505P is no longer available, at least from the usual suppliers. The
closest equivalent I found here in Argentina is TI's TL7705 (a close match
to the original part, datasheet attached).

A word of warning, though: when replacing TA8505P with an equivalent, such
as the TL7705, a couple of changes to the MI-003 board may have to be made
for it to work. I'll explain the changes needed for this particular , but
there may be some drop-in replacement available in your country.

If you look at the schematic I attached, the MI-003 board has a resistive
voltage divider on pin 7 of IC15. R26+R15 drop Vcc (5V) to ~1.4V so the
TA8505P can compare with its internal reference voltage, set at 1.3V.

The thing is that while on the TL7705 the reference voltage is the same,
the resistive divider is internal. So, it must receive Vcc directly on pin
7 to work properly. The easiest way to achieve that is replacing R26 with a
jumper wire, and removing R15. I also attached the board location of these
changes.

tl;dr if you have an unresponsive K5/K5m with a black screen, try booting
it with IC15 removed. If it kind of runs without it, then IC15 must be
replaced. The chip is no longer available but similar ones may work fine,
provided you know what to mod. YMMV.

Thank you all for your assistance. This group provided me of everything I
needed to work on this synth.

Alejandro

PS the service manuals, board layouts and schematics available for the K5
are a great tool, but they have some print errors on them: some components
and pin numbers are mislabeled, so proceed with extra care when
troubleshooting.

On 5 July 2016 at 16:15, Alejandro Caceres <[email protected]> wrote:

> Antoine,
>
> I ended up tracing the problem to the reset circuit, after some more
> troubleshooting I'll be able to come up with a definitive fix. If anything,
> the synth runs without IC15 (TA8505P Supply Voltage Supervisor) but it
> starts only once every two or three tries, naturally because it's missing
> the reset circuit.
>
> I'll document everything wrong with it and the definitive fix once I find
> the root cause of the problem.
>
> tl;dr: if you have a dead K5 or K5m with a black screen, check the reset
> circuit and IC15 / U15.
>
> Thanks again.
>
> On 5 July 2016 at 13:24, Antoine Deschênes [email protected] [k5synth] <
> [email protected]> wrote:
>
>>
>>
>> It might not be the actual cause, but look for cracked solder joints,
>> especially on the power supply PCB, it can cause lots of intermittent
>> problems, power aupply noise and weird voltages all around. Ideally, rework
>> every single solder joint on that PCB. If the backlight is dead, it would
>> be worth disabling the inverter.
>> Le 2016-07-05 12:10, "Alejandro Caceres [email protected] [k5synth]" <
>> [email protected]> a écrit :
>>
>>>
>>>
>>> I made it start!!
>>>
>>> Something seems broken on the K5m's reset circuit, I lifted IC15 (the
>>> reset controller) and now the synth starts one out of three times, so it
>>> needs fixing there. Once it starts everything seems to work ok so I'm on
>>> the right track.
>>>
>>> Thank you very much for all your help.
>>>
>>> On 30 June 2016 at 15:48, Alejandro Caceres <[email protected]> wrote:
>>>
>>>> I programmed both EPROMs, and the synth still refuses to start. Also
>>>> tried removing and replacing the onboard battery to clear all settings,
>>>> checked the PSU voltages and loose cconnections to no avail. With some help
>>>> from the schematics and a oscilloscope I traced the problem to the main CPU
>>>> halting shortly after startup.
>>>>
>>>> I tried operating the synth without the screen to see if the problem
>>>> comes from the LCD or from somewhere else, but it doesn't seem to respond
>>>> to any commands I send from the MIDI controller, regardless of the channel
>>>> or mode I set.
>>>>
>>>> Does anyone know what the "out of the box" MIDI defaults are for the
>>>> K5m?
>>>>
>>>> On 9 June 2016 at 15:13, Alejandro Caceres <[email protected]> wrote:
>>>>
>>>>> I have just checked IC26 on my K5M, and the code is the same so it
>>>>> should work.
>>>>>
>>>>> I'll program the EPROM and let you guys know if it works.
>>>>>
>>>>> Thanks again,
>>>>>
>>>>> Alejandro
>>>>>
>>>>>
>>>>> On 8 June 2016 at 22:11, Alejandro Caceres [email protected]
>>>>> [k5synth] <[email protected]> wrote:
>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks Jeroen!!!!
>>>>>>
>>>>>> This will no doubt help fix my K5M. Will check if the EPROM code
>>>>>> tomorrow afternoon and will let you know if it's the same on the K5 and K5M.
>>>>>>
>>>>>> Thanks again,
>>>>>>
>>>>>> Alejandro
>>>>>>
>>>>>> On 7 June 2016 at 18:41, Jeroen Oldenhof [email protected] [k5synth] <
>>>>>> [email protected]> wrote:
>>>>>>
>>>>>>>
>>>>>>> [Attachment(s)
>>>>>>> <#m_122267622150572167_m_8852184931021894320_m_3281220585771295443_m_-1941349435899099343_m_-936213366833815860_m_-1725616739064271066_m_456838618377690730_m_109644857595712275_TopText>
>>>>>>> from Jeroen Oldenhof included below]
>>>>>>>
>>>>>>> Hi guys,
>>>>>>> I just uploaded the file 'KAWAI-K5-IC26-P015-M4DF.bin' in the
>>>>>>> K5OS1.3 & K5M OS1.2' subfolder of the k5synth files section on yahoo groups.
>>>>>>> Not sure if this is the right place, but additional subfolders don't
>>>>>>> seem really necessary to me..
>>>>>>>
>>>>>>> Just to be sure, it's the dump of this IC:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Hope this is useful!
>>>>>>>
>>>>>>> Best,
>>>>>>>   - Jeroen
>>>>>>>
>>>>>>>
>>>>>>> Op 3-6-2016 om 16:35 schreef Jeroen Oldenhof [email protected]
>>>>>>> [k5synth]:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> I have a K5 and an EEPROM programmer. If this chip is equal to the
>>>>>>> one in the K5M, I will extract it and dump its contents this weekend.
>>>>>>>
>>>>>>> Best,
>>>>>>>   - Jeroen
>>>>>>>
>>>>>>>
>>>>>>> Op 3-6-2016 om 16:33 schreef Daniel Forró danforcz-/[email protected]
>>>>>>> [k5synth]:
>>>>>>>
>>>>>>>
>>>>>>> Try to ask Grant at Music Technologies Group, he has some files for
>>>>>>> K1m and mentioned 27C256 here:
>>>>>>>
>>>>>>> http://www.musictechnologiesgroup.com/mtg_eproms.htm
>>>>>>>
>>>>>>> Good luck!
>>>>>>>
>>>>>>> Daniel Forro
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Jun 3, 2016, at 11:02 PM, Alejandro Caceres <[email protected]>
>>>>>>> [email protected] [k5synth] wrote:
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Hi Antoine!
>>>>>>>
>>>>>>> Thanks for the heads-up. I just got a response from the Kawai US
>>>>>>> tech support line, they provided me with the 64kb K5M v1.2 system ROM, but
>>>>>>> not with the file for the 32kb 27c256 IC26 EPROM.
>>>>>>>
>>>>>>> If someone else got that file at hand please let me know.
>>>>>>>
>>>>>>> Thanks!
>>>>>>>
>>>>>>> On 30 May 2016 at 18:16, Antoine Deschênes  <[email protected]>
>>>>>>> [email protected] [k5synth] < <[email protected]>
>>>>>>> [email protected]> wrote:
>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> I could dump from a K5 eventually. My K5 as well as the EEPROM
>>>>>>>> reader are quite far from my new place right now, so I can't do it very
>>>>>>>> soon. I guess if the sticker on the EEPROM matches between the two synths,
>>>>>>>> it should work just as well. You could try getting the ROM file from Kawai
>>>>>>>> US or Kawai UK, they usually give them by email but they don'T have all of
>>>>>>>> them.
>>>>>>>>
>>>>>>>> Cheers,
>>>>>>>> Antoine
>>>>>>>>
>>>>>>>> --
>>>>>>>> Antoine Deschênes
>>>>>>>>
>>>>>>>> 2016-05-30 17:05 GMT-04:00 Alejandro Caceres [email protected] [
>>>>>>>> k5synth] < <[email protected]>[email protected]>:
>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I am working to fix a K5M modular synth, which for some strange
>>>>>>>>> reason had both EPROMs corrupted (IC29 and IC26).
>>>>>>>>>
>>>>>>>>> I already made a replacement for IC29: sourced a 27C512 chip and
>>>>>>>>> burned it with the K5M v1.2 system software.
>>>>>>>>>
>>>>>>>>> However, I cannot find the 32kb file to program the IC26 27C256
>>>>>>>>> chip anywhere.
>>>>>>>>>
>>>>>>>>> Does anyone have the file for that chip? Or, maybe someone with a
>>>>>>>>> EEPROM reader and a working K5M can make a ROM dump for me?
>>>>>>>>>
>>>>>>>>> Thanks in advance!
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>>
>>> 
>>
>
>