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2016-04-06 by phijel
Hello,
I've built this and it works fine, excepted (perhaps) for 2 small issues :
- the direction jack only works if the direction switch is set to reverse
- the reset jack works fine in forward mode, but doesn't work when in reverse direction
Is it normal behaviour or do you think it comes from a build error ?
Thanks for your insight
Philippe
2016-04-06 by Ken Stone
On Wed, Apr 6, 2016 at 9:15 PM, philippe@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:Hello,
I've built this and it works fine, excepted (perhaps) for 2 small issues :
- the direction jack only works if the direction switch is set to reverse
- the reset jack works fine in forward mode, but doesn't work when in reverse direction
Is it normal behaviour or do you think it comes from a build error ?
Thanks for your insight
Philippe
--
2016-04-12 by phijel
2016-04-12 by Ken Stone
Should I try to switch the cables going to UD and SW and see what happens ?You could, or add another 47k in series with the switch and see if that helps.
Regarding the reset issue in reverse mode, I checked the parts you said, the 547 is placed following the silkscreen, the associated diodes are placed correctly and behave normally when tested. I have no way to test the pinout on the transistor though (my transistor tester doesn't work any longer apparently). But it comes from the same batch than the 8 others controlling the led and gate outputs, which are behaving correctly, so I doubt the problem come from it. I also tried to swap it for another 547, but with the same resultsTry a different chip. Look for soldering problems. Make sure a pin of the chip isn't bent underneath. When in DOWN mode, the chip's PRESET function is used to load the counter with HIGHs (i.e the eighth step in binary).
2016-04-13 by phijel
2016-04-13 by Ken Stone
It's fine. It is a very low current. In reality, anything you plug into it will totally swamp it.
- some of the resistors marked 10k on the silkscreen (and the BOM) are 15k on the schematic (after UD, CLOCK and INH). What value should I use ? (I tried 15K instead of 10K on UD, but doesn't help)
Either will work. 15k were in the VER1.0 PCB.
Thanks. The chip looks fine, but no spare to try unfortunately...
I had 2 more questions maybe related to this :- I noticed when the switch is set to UP, the direction jack is in fact outputting +10V. When looking at the schematic, it looks like it cannot be otherwise because it is directly connected to the +15v from the switch through a 47k and a 15k resistor... Am I missing something here ?- some of the resistors marked 10k on the silkscreen (and the BOM) are 15k on the schematic (after UD, CLOCK and INH). What value should I use ? (I tried 15K instead of 10K on UD, but doesn't help)