SV: [sdiy] A new variety of DK600 problem...after all that...won't store!

[karl dalen]

Hmmm!

DK600=Opera 6?

Is it a Z80?

What about missaligned *write timing* to SRAM! A buffer or RC net to delay!

Or!

This stored when powered and lose memory content when turns off is a typical
to early de-enable thing on SRAM or there might be enable glitch when power
is turned off wich empties memory before battery voltage is available to the
SRAM. Check the one way diodes thats feed the SRAM from mains power
cirquit and the diode that comes from the battery.

Besides that it might be anything! :-)

--- Bob Weigel <sounddoctorin at imt.net> skrev:

> I know...95[enter] turns off protect.  The synth *seems* to function 
> perfectly after replacing a bad dac buffer, adc comparator, and a 
> 74ls377 that drives a bunch of led's.  ..and cleaning up and rebuilding 
> the battery area of course.
> 
> However...I see data getting to all the right lines when I press 
> 'record' but even after 95 [enter] you cannot ever get the LED's to 
> flash indicating 'pending store'.  Strangely it seems to store anyway 
> until you turn it off sometimes.  I haven' tried to correlate that 
> phenomena.  But hey..I've swapped SRAM, CPU, EPROM..and the inverter 
> chip that seemed to be putting out a slightly deficient signal to the 
> output enable.  Still does the same thing.  Installing a 6116-4 btw 
> creates some really bizarre effects -). A little too slow apparently.  
> You get a fourth LFO!!!  You just..ahem..can't ..like turn it off or 
> anything.  :-)  .7sec period roughly. hehe.  Nasty segmented envelopes 
> too... -Bob
> 



	
	
		
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