Arpeggiator rate knob

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Arpeggiator rate knob

Postby oldgearguy » 12:44, 30 March 2016

New V-Synth user here (but not new to synthesis). Question -- I have a V-Synth (OS 2.0) and I've been programming some patches and wanted to use some slower tempos on the arpeggiator with the clock set to internal.

The knob (and range on screen) says 40 -> 240 with 120 in the middle, but when I turn the Arp Tempo knob it only goes down to 86 and then turning it back up, the middle ends up being anywhere from 120 to 139 or so and it reaches 240 before the full travel clockwise.

My question is -- is this normal? i.e. - does the knob really only go down to 86 and you need to use the screen to set a lower tempo or does this particular machine need some attention?

thanks
oldgearguy
 
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Re: Arpeggiator rate knob

Postby Rodan » 02:25, 6 April 2016

Hi oldgearguy,

Welcome to the clan. I checked my V-Synth GT and the rate can be changed from 20 to 250 using either the tempo knob at the left, the E1 knob below the screen or the big wheel on the right. However, my screen does not show a range, so maybe this isn't a comparison of identical hardware or software.

You've got me curious now, so I'll poke around a little more and post back here if I find anything.

Rodan
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Re: Arpeggiator rate knob

Postby Rodan » 20:20, 6 April 2016

Looking into it a little more, it appears that you should always be able to get the 20 to 250 range. I'm going to assume that the "arp tempo" knob you are referring to is the E1 knob below the display since that is the one that has a limited range. If that is the case, then it looks like that knob has a bad pot or encoder, whatever they use. You might be able to check it out by switching to a different screen for which the E1 knob controls a different parameter and see if again it doesn't give you the full range you are expecting.
Rodan
 
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Re: Arpeggiator rate knob

Postby oldgearguy » 13:22, 5 May 2016

to follow up -- no it's not normal. This particular V-Synth (from a tech that said it was in great condition no less) apparently had something heavy dropped on it or maybe the inadequate packing allowed it to get kicked/battered to the point that there was a crack in the Panel-L board which is causing the weird behavior around C1/C2/Arp rate knobs.

The odd thing is that the weirdness also affects the aftertouch. If I go into diagnostics, I can see the C1 knob value slowly creep across the display without me touching the knob if the knob is in the full off/0 position. This constant false signal is enough to skew the value of the Arp rate knob and to keep the processor busy enough to ignore aftertouch. I don't know what kind of internal multiplexing/polling is taking place, but it's a clear relationship. If I turn the C1 knob away from minimum, aftertouch works 100% and the Arp rate knob goes from 40 to 240 as designed.

The crack was also responsible for keeping the LED under the 'V-Link' button from coming on. I'm in the process of jumpering across the crack and checking to see if the C1 pot itself is damaged. If so, I'll need to track down another one.

Again the reminder to have a seller run the diagnostics page and verify everything is working as it should.
oldgearguy
 
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Re: Arpeggiator rate knob

Postby Rodan » 03:03, 8 May 2016

Wow, a cracked board! That sort of thing pretty much throws armchair trouble shooting out the window. Glad to hear you tracked down a problem. Best of luck to you with the repairs.
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Re: Arpeggiator rate knob

Postby oldgearguy » 17:06, 9 May 2016

Rodan wrote:Wow, a cracked board! That sort of thing pretty much throws armchair trouble shooting out the window. Glad to hear you tracked down a problem. Best of luck to you with the repairs.


Thanks. It's been a headache, but I have all the traces repaired and I found someone selling new potentiometers that match the C1/C2 specs, so I'm replacing them as well. Once that's done, the board and V-Synth should be solid and good as new.

Like I said - I am doing a fair amount of preventive jumpering in case it ever takes another inadvertant hit some time in the future.

Years ago I bought a Jupiter-8 cheap because it was randomly locking up/powering off. After a week+ of tracing circuits I was no closer to a solution until one day when I had the lid raised, the sun coming in through a door fell on the regulator board just right and I could see a crack. The JP-8 must have fallen on its heatsink and the regulator board cracked which was causing the intermittent failures. Jumpered over the crack and it was good to go, no other issues.
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Re: Arpeggiator rate knob

Postby oldgearguy » 15:21, 26 May 2016

Just a follow-up to say I did get it all fixed, replaced the 2 pots (C1 and C2) out of caution, and after playing around with it extensively have decided to sell it. It's listed in the classifieds: http://forums.rolandclan.com/viewtopic.php?f=7&t=52007

My overall take is that it's an amazing synth and I thought it might be able to replace my Octatrack and Prophet 12, but in the end the separate boxes approach works better for me. An unexpected opportunity to purchase a GRP A4 came up and so the V-Synth (and some other gear) is up for sale.
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