[sdiy] Spare MN3009 for Juno 106

[john slee]

Very handy page, thanks Tom! My 106 has the dreaded noisy chorus too...
[and other problems that may finally push me over the "ok ok fine I'll buy
a desoldering station" threshold]

I picked up a couple of MN3009s of unknown provenance but this may well be
a better plan

John

On 17 June 2018 at 10:35, <rsdio at audiobanshee.com> wrote:

> That’s a handy page.
>
> Parts are so cheap today that I’d recommend replacing the 8.2 kΩ resistors
> with 2.05 kΩ resistors. You have to buy 1% resistors, probably metal film,
> to get that value, but they’re only $0.10 in single quantity, so shipping
> will be more than that anyway.
>
> The reason I say this is that the 2.2 kΩ suggestion on that web page could
> be as much as 13% too high, resulting in a longer delay than original.
> Assuming the factory resistors are 5%, the 2.2 kΩ resistors could change
> the tone of the chorus.
>
> It’s cheap enough to literally divide the original resistor values by 4
> and just spend a few pennies more to keep the delay times as close to
> original as possible.
>
> I didn’t see resistor values for anything besides the Juno 106, so I
> didn’t look into it any further.
>
> Brian
>
>
> On Jun 16, 2018, at 1:55 AM, Tom Wiltshire <tom at electricdruid.net> wrote:
> > It doesn’t sound that difficult, actually:
> >
> > http://www.florian-anwander.de/roland_string_choruses/
> index.html#comments
> >
> > Replace the MN3009 with MN3007 (which aren’t so impossible to find) and
> then change a couple of resistors to boost the clock frequency. Pretty
> straightforward.
> >
> > On 16 Jun 2018, at 06:35, Ian Michael Ferguson wrote:
> >> I'm afraid that's above my pay grade. :)
> >>
> >> On Fri, Jun 15, 2018 at 9:24 PM Jackalope Billy wrote:
> >>> What about substituting another MN30xx chip and just modifying the
> circuit to make it work?
> >>>
> >>> On Fri, Jun 15, 2018 at 10:49 AM, Dave Magnuson wrote:
> >>>> It’s such a bummer, too. Small Bear has a couple flavors of the
> MN30xx chips, but alas, not the 3009
> >>>>
> >>>> From: Ian Michael Ferguson
> >>>> Sent: Friday, June 15, 2018 1:03 PM
> >>>>
> >>>> Oy...the nightmares are coming back to me.
> >>>>
> >>>> I searched long and hard a few months ago for the "106 Chorus"
> eurorack module.
> >>>>
> >>>> You either had to buy a whole salvaged chorus section to take used
> chips out of, or risk one of the eBay vendors which are frequently bogus
> counterfeits.
> >>>>
> >>>> The only thing I didn't try was calling around repair shops, who
> might have old stashes.
> >>>>
> >>>> Maybe Switched On?
> >>>>
> >>>> If you find a reliable one, please let ME know. :)
> >>>>
> >>>> -Ian
> >>>>
> >>>> On Fri, Jun 15, 2018 at 6:50 AM Tom Wiltshire wrote:
> >>>>> Does anyone know where a person might be able to get hold of MN3009
> for a Juno 106 chorus repair?
> >>>>>
> >>>>> Someone was asking me about it, so I said I’d enquire here on their
> behalf.
> >>>>>
> >>>>> Thanks,
> >>>>> Tom
> >>>
>
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