#444

So, I’m thinking about getting into eurorack, and I’ve put together something in modulargrid… :wink:

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#445

@GoneCaving - damn funny!! I burst out laughing on my plane. :wink:

So - if you’ve been following the other threads, you will most likely be aware that in order to reliably connect more than 3-4 devices to your Teletype, a mechanism is needed to provide more “pull-up” on the ii bus. This can be accomplished by modifying your Teletype or by using an external bus board that provides the additional needed pull-up. (You can also hack the firmware on one of the Teensy on your expanders, but this is not recommended as it may put too much strain on the devices on your bus.)

There are now two powered DIY bus board options for the Teletype ecosystem that @tehn has kindly designed for the ii expansionist. One is designed to sit in your case and one is designed to mount on the back of your Teletype. I’m calling them the iiBusboard and the iiBackpack to keep myself sane.

iiBusboard

image.png2301×201 5.42 KB

iiBackpack

image.png1651×458 7.6 KB

I’m assuming that many who have reserved the pending expanders might like one of these puppies. They are DIY and quite simple to build - only 3 SMD parts that should be trivial to affix even for novices. That said, I’m also assuming that there are plenty of folks on the list for whom DIY isn’t their thing.

So - we need to figure out how to get these out there. I’ve added a couple of columns to the list for these peripherals. PM me if you will need one and indicate your preference. I’ll share the numbers in a few days and then we can figure out how to get this taken care of without delaying the expanders. :slight_smile:

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A user's guide to i2c
A user's guide to i2c
#446

If I could “heart” this post again, I would.

1 Like
#447

That’s fair amount of PCBs, my guess is that this whole project scale went up quite beyond the initial expectations :slight_smile:
Thanks for info on ii bus problems and possible solutions, keep up the good work!

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#448

do u have grayscale panels for this plz???/

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#449

Thank you for the plain English and extraordinarily thoughtful description. Now if someone would just define “pull up” :slight_smile:

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#450

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#451

Whew, and here I was thinking it was something I was unfamiliar with.

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#452

Perhaps closer to the mark:

https://learn.sparkfun.com/tutorials/pull-up-resistors

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#453

I’d suggest moving the TXi’s to the top row so patch cables aren’t obstructing the knobs :wink:

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#454

with the iiBackpack on the back of the teletype, will it still fit in an isms?

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#455

yes! still only 35mm or so.

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#456

cool. definitely in for an iiBackpack.

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#457

Off to the races with assembly! Did the first 3 of each module this weekend to kick off the process. Here they are - QC tests passed with flying colors:

Used an extra PCB flipped backwards with female headers to help with positioning the male headers on the back:

That made a tricky part of the process much easier!

There are a lot more to build and I will not be shipping until I’m done with the assembly and testing process. Also - these first six took a lot longer to assemble that I was expecting. Could be due to context switching between the units. Let’s see tomorrow when I start working to hit my daily quota while still going to work. :expressionless:

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#458

I am just about to order the parts for both modules and noticed that when using the mouser BOM posted above I got some parts that look the same (as the 470R resistor or the 1uf caps) but I got different devices in the cart at a different cost.

Is there something I miss about those doubles or can I just merge the two lists, add quantities up to 10 and get the cheapest resistors and caps I find as long as package sizes and values do fit?

It will be my first SMD soldering project and I don’t want to mess it up of course…

#459

Apologies - you found some competing parts from different dev runs. Those are in my original BOM - but when I did my big order I coalesced them into the following:

470R - Mouser # 660-RN731JTTD4700B25
1u - Mouser # 581-06033C105KAT2A

I’ve updated the BOMs accordingly.

Please let me know if you have additional questions.

TELEX HANDY LINKS
TELEX Microsite | Ordering Process Details
Crazy Verbose Status + Timeline | Printable Command Reference

1 Like
#460

Great - thank you for clarifying this!

I am sure it was a stupid question. I just have a lot to learn while building those modules and I really appreciate your support and all the effort you invest in this project!

:slight_smile:

#461

@Leverkusen - Not a stupid question at all; I had two different Mouser part numbers for the same part across the two modules. I’m glad you caught it so I could fix the BOMs. Funny thing is that I just ordered some additional parts ten minutes before your posting and stupidly purchased the different versions of the same part. :rolling_eyes:

When you buy your SMD parts, know that sometimes it is less expensive to buy more parts than you need due to the volume pricing. This is also good because all it takes is a good sneeze or a playful cat to have your tiny passive components disappear into a carpet or dust pile.

Please reach out if you have any trouble at all during the build. There are some tips on the microsite - I highly suggest reading them. The PDF build guides will save you a lot of time hunting for part locations.

One of the thing that gets me from time to time is that you need to install the top header that connects the two boards together before you install the potentiometer or jack on each expander. That way you can ensure that the leads are trimmed down to be board level (I do it before soldering) and won’t short out against the component that is installed on top of them.

Good luck!!

b

TELEX HANDY LINKS
TELEX Microsite | Ordering Process Details
Crazy Verbose Status + Timeline | Printable Command Reference

#462

Telex Update

Production of the Telex units is going well - but way slower than expected. At every turn, I’m underestimating how long it is going to take me to do each step. What does this mean for my timeline?

Well, I am not going to meet my first week of April date. I’ve been killing myself to go as fast as possible and it just isn’t going as quickly as I need it to in order to make my target. I’m bummed too, btw. I’ve been looking forward to getting this part behind me. I think there is at least a month more of work to go - but don’t quote me. Clearly I don’t know what the hell I’m talking about. :wink:

I’ve updated my Crazy Verbose Status + Timeline above - go check it out if you want detail on each and every step. At a high level, I’m almost done with assembly with all of the TXi units. Here are some of them:

I’ve tested a few and things are looking good - but the rest are still in the pipeline to get verified.

I first was trying to do an end-to-end on eight at a time. That was a nightmare - and slow as hell. I was a nervous wreck trying to get the first eight done without making mistakes. (My back was killing me. I had a splitting headache. It was not working.)

I’ve since moved to a “one step at a time across all units” approach. That is way easier on me and way, way faster. Here are some TXi from earlier in the week waiting to get their board to board headers installed.

You can see that the top potentiometer is not yet installed; the trick is not to do that until the balancing header at the top of the board is trimmed and installed to avoid shorts.

One of the things that took a boatload of time was prepping the pots; taking the screws and spacers off and clipping off the little anti-rotation nub. I’m never buying pots that have those stupid things still on them again. (Unfortunately, it was the only source I could find where I could get the volume we needed in time.)

I designed and 3D printed a little assembly frame (it is in the extras folder) that has made soldering components to the boards way easier. I put four little rubber feet on the bottom and it keeps things in place while I’m doing the assembly. Super-handy!!

I’ll keep you updated as I progress. Expect my next post when the TXi are done.

Cheers!

b

TELEX HANDY LINKS
TELEX Microsite | Ordering Process Details
Crazy Verbose Status + Timeline | Printable Command Reference

17 Likes
#463

This all looks amazing! Thanks for the updates! :control_knobs::control_knobs::control_knobs::control_knobs::radio_button::radio_button::radio_button::radio_button:

3 Likes