Easel 2 stage sequencer glitch

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hylaster
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Easel 2 stage sequencer glitch

Post by hylaster » Thu Sep 12, 2019 11:07 pm

Hello all. I have a BEMI Easel comprised of a 2016 208 and a 1st rev 218e (but with updated PSU.)

I was experimenting with switching the 2 stage sequencer option via an aux card, and now - with the card removed - the Easel no longer has a 3 stage option. In the 3 stage position it's on 2 steps. 4 and 5 step positions work fine.

Any ideas?
Thanks!
Last edited by hylaster on Fri Sep 13, 2019 10:26 am, edited 1 time in total.

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lumin
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Post by lumin » Thu Sep 12, 2019 11:34 pm

This happened to me within the past month. Had to change a resistor on the sequencer card. There is a thread about it:
viewtopic.php?t=180014&sid=8e072d266867 ... 00df41950b
The 2nd muff link in that post shows you which resistor to change.

Replacement was super easy.
Good luck

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search64
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Post by search64 » Fri Sep 13, 2019 3:30 am

This error is very common in the DIY Easels. I think the fix (it's been a while since I made mine) is to add a decoupling cap to the ICs on the sequencer card.

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ArguZ
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Post by ArguZ » Fri Sep 13, 2019 3:41 am

Card 1 needs to look like this on the back..
https://modularsynthesis.com/roman/buch ... 1_rear.png
Does it ?

christie
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Post by christie » Fri Sep 13, 2019 10:26 am

If this is a BEMI Easel, then lumin is correct, the incorrect value resistor is often the culprit. On mine, though, it turned out I had the correct value resistor, but still got the problem one day. I sent the sequencer board to Buchla USA and they found a bad inverter chip that need to be replaced. Turnaround was super quick.

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hylaster
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Post by hylaster » Fri Sep 13, 2019 11:49 am

Yep, it's a BEMI. Thanks for the replies! I will check that resistor value.

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hylaster
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Post by hylaster » Sun Sep 29, 2019 11:07 am

Turns out my 208 already had the 120k resistor but the quad inverter chip was failing. So apparently that's something that can happen, FYI. Chip replaced, all better now.
Thanks again for the tips!

christie
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Post by christie » Sun Sep 29, 2019 12:55 pm

Yep, that's exactly what hit mine. Hmmm.

diller
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Post by diller » Sun Sep 29, 2019 1:08 pm

I had this with my early BEMI Easel too and it was the inverters. It is a common issue.

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Cobramatic
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Post by Cobramatic » Sun Sep 29, 2019 7:22 pm

This has happened to me intermittently too (BEMI Easel) - always after I used an Easel card or my custom BOB to cv the number of stages in the sequence.
Sometimes after removing the card the number of stages changed by the panel switch would be 2 or 4. It always seem to magically fix itself later or by using the card again.
Mine was a relatively early BEMI Easel and I've never checked which resistor I had installed.

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ArguZ
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Post by ArguZ » Mon Sep 30, 2019 7:20 am

The clones have that too...
It's a thing...
it is probably something related to the pulser not going all the way down to zero as mentioned in the other thread..
It's a design thing.
Like the unbuffered outputs or the weak reverb.
Fingers crossed it is been addressed in the 208C

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