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cctsim
Silver Member
United Kingdom
418 Posts |
 Posted - 08/15/2008 : 21:49:20
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Hi Guys
My DS1 starts for some reason always in ON mode. Is there a quick way to reverse the state.
I am planning to swap Q4 and Q5 but since the board is a bit sensitive to soldering I thought it is worth asking first here.
Is there a definitive solution to this problem ?
Best Regards
cctsim |
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Laurie
Double Platinum Member
Canada
4854 Posts |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 08/15/2008 : 22:35:24
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Laurie, many thanks for the link.
It seems there are two suggestions:
1. swap Q4 and Q5
2. Lower R31 to something like 33k or 22k
I 'll try them both tomorrow.
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 08/19/2008 : 00:11:50
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| I swapped today R31 with R30 and it does the trick, no need to swap the transistors. Now I need to apply this change to a few more pedals...easy trick though. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/19/2008 : 15:03:32
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quote:
Originally posted by cctsim
I swapped today R31 with R30 and it does the trick, no need to swap the transistors. Now I need to apply this change to a few more pedals...easy trick though.
Hi cctsim
Did you measure the values of R30-R31, before you sapped them?
I was wondering how much difference in value there was between the two resistors.
Will you please be kind enough to do this measurement, while you are modding your other pedals?
Regards Dr. Bob |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 08/19/2008 : 15:47:09
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Hi Guys
Here is a picture (fragment), outlining the simple wake-up state mod.
Parts to swap are outlined in light blue.
For those that may (may not) have notice.
I have adopted the light blue colour (& for our US friends-color),
as the un-official colour I use when editing or modifying things on the forum.
Schematic Fragment: ©Boss/Roland.
Regards Dr. Bob
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 08/19/2008 : 19:37:42
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I 'll measure the difference between R30 and R31 tomorrow. I have a few more pedals I'd like to convert to default to off. Given the 5% tolerances I guess the difference could be up to 5.6k (min-max).
This is a picture of the current DS1 board. D8 is now replaced by J4.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 08/19/2008 : 19:56:47
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| Thanks for this thread guys... it's info I've been meaning to figure out for ages. |
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 08/31/2008 : 21:49:31
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I have converted now 5 pedals to start in off mode. To summarize my findings, swapping the corresponding R30 and R31 in the flip flop is not a universal solution.
It worked fine in 3 out of 5 cases. In one of the two pedals that it didn't work, the measured values of the resistors was R30=55.3k and R31=55.7k.
I then measured and swapped the remaining resistors (R26, R27 and R28, R29) and found them to be very closely matched, e.g. the difference was less than 400 Ohms. In this case, swapping all resistors didn't change the starting state.
I proceeded by swapping the transistors Q4 and Q5 and this did work.
Unfortunately, I don't have an LC meter to measure the capacitors in the flip flop to get the full picture,
In summary, if you want to change the starting state of a pedal, swap the R30 and R31. If this doesn't work swap Q4 and Q5.
I would be interesting to hear if somebody tried both changes with no success.
Best Regards
cctsim
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cctsim
Silver Member
United Kingdom
418 Posts |
Posted - 08/31/2008 : 22:14:02
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One more thing. If you lower R31 to 33k works 100% in all cases.
However, this results in undesirable "popping" noise when you switch the pedal on/off. So it's a "no go". |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 08/31/2008 : 22:56:29
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| THANK YOU for the info! |
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Topic |
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DS1 starts in ON mode
