[sdiy] TR-606 stuck on one step patterns?

[Tony Kalomiris]

Hi Tom,

I'd check the usual things first before blaming it on bad chips.
Cold solder joints, cracked pcb, broken traces, pads lifted..dirty switches etc.
Then I'd check the actual switches (Function) with unit powered off for continuity.
An inexpensive logic probe can help you see if there is activity on the cpu, ram, and logic - very handy.
It's very hard to troubleshoot something like this without seeing the machine it could be anything, even a RAM ic (1K x 4) you can still get those.

Sorry if this isn't very helpful, maybe some other fine folks can share their opinions.
I seem to recall this sort of problem, and it might have required replacing one or more SRAM chips, but that was a long time ago and I can't be sure.

Tony Kalomiris


On 2010-12-04, at 12:15 PM, Tom Bugs wrote:

> Ah, no - that's the problem! - I *can't* change the pattern lengths!
> 
> Eg - in pattern write with clock stopped I can use the buttons to select a pattern. Pressing Run/Stop starts the clock going and step 1 flashes (I can then program/turn-off each drum hit on this single step). Usually I would press and hold the Function button and then select a Last Step, but this is not working...  The Scale slide switch also has no effect and this would be changed when the Function button is pressed while running.
> 
> Actually, when I press the Function button while running in pattern write it is lighting up the LED for step 9 (along with Step1 Led flashing with the tempo) but still it is stuck on a 1step pattern..
> 
> There's no battery backup in this as the battery case parts are missing at the moment. I don't *think* that'd affect things other than patterns not being saved on power down?
> 
> Cheers,
> Tom
> 
> On 04/12/2010 16:20, Senso wrote:
>> Sounds like the same problem that can happen to a TR-808. Just go in programming mode and set the pattern length to 16 again. That helps in 99% of the cases.
>> 
>> Senso
>> 
>> PS: Check the backup battery too. It never hurts. ;-)
>> 
>> 
>>> I wondered if anyone could suggest any pointers for this TR-606 trouble:
>>> 
>>> I got the machine in busted state a good few years ago - the back of the case / battery box a bit broken up and with small damage to the PCB corner near the power entry. After a few resurrection attempts I got it working again and it has been happy for a few years. I've not used it now for a few months, but when I came back to it again it has developed a problem - Run/Stop works fine, as does pattern select and the drum voices, but all patterns are stuck to 1-step lengths. The Function button (SW7 on the switch sub-board) does appear to be good, but I'm a bit stumped from there.
>>> 
>>> If anyone has any pointers or experience with such a problem it'd be great to know. Dead CMOS? Dead central CPU? Electro cap problems?
>>> 
>>> Thanks in advance for any help possible.
>>> Tom
>> 
> 
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