Bourns Again - Bourns 601 Series RC Network T-Filters Replacement

[JDW]

I actually just did the model for exact replica of [the mounting bracket for Reset & Programmer's Switches].

JLCPCB can do stainless steel 3D printing now...

Holy cow! That's incredibly useful info! Thank you for posting that!

Personally, to bring down the cost in time and money of the SE Reloaded board I would love to see or do an updated board with surface mount components for all the resistors and capacitors. Theoretically the filters could also just be assembled on the board and maybe leave the footprint for the dip packages just in case. CR2032 battery holder would be nice.

I covered the 2032 battery in my video series, explaining it would get less battery life than the original, which is partly why I deliberately installed the stock holder instead of a CR2032 holder. So long as one could get the Reloaded PCB partly pre-assembled with those SMD passive components soldered onto it, at a cost (with shipping) of no more than buying and installing the discrete components., then I agree about there being a benefit But if one didn't get it assembled, it would become a problem, I think. SMD soldering even for someone experienced like me is no fun at all, and such would have taken me much longer because I don't have the right equipment (i.e., I don't have a US$500+ microscope like Bruce Rayne and Mac84 have). Even if I had a $500 microscope, most people buying the SE Reloaded board still wouldn't, so the difficulty associated with surface mount soldering for the masses remains. Also, if you accidentally pinch a teensy tiny SMD part such that it accidentally pops out from your hand and flies across the room, that component is gone for good! And yes, that applies to Mac Classic Reloaded because it's an SMD build. With thru-hole parts on the SE Reloaded board, you're not going to lose parts by accident, even if you accidentally toss a small part like a 1N4148 diode across the room.

Another issue is aesthetics and "the stock look." If somebody wants a board to look exactly like the original (maybe changing only the PCB color), then what we have now will allow for that. I've even been told the same about the PRAM battery. Some people know that battery carries with it more risk if left in there for more than 6 or 7 years, but they still want the stock look (and greater battery life).

Anyway, thank you for sharing this incredibly useful info!

 

[alxlab]

I covered the 2032 battery in my video series, explaining it would get less battery life than the original, which is partly why I deliberately installed the stock holder instead of a CR2032 holder. So long as one could get the Reloaded PCB partly pre-assembled with those SMD passive components soldered onto it, at a cost (with shipping) of no more than buying and installing the discrete components., then I agree about there being a benefit But if one didn't get it assembled, it would become a problem, I think. SMD soldering even for someone experienced like me is no fun at all, and such would have taken me much longer because I don't have the right equipment (i.e., I don't have a US$500+ microscope like Bruce Rayne and Mac84 have). Even if I had a $500 microscope, most people buying the SE Reloaded board still wouldn't, so the difficulty associated with surface mount soldering for the masses remains. Also, if you accidentally pinch a teensy tiny SMD part such that it accidentally pops out from your hand and flies across the room, that component is gone for good! And yes, that applies to Mac Classic Reloaded because it's an SMD build. With thru-hole parts on the SE Reloaded board, you're not going to lose parts by accident, even if you accidentally toss a small part like a 1N4148 diode across the room.

For me personally, my view of the SMD version of the board would be to have it pre assemble at the PCB manufacturer to reduce time and cost. With JLCPCB assembly service it would be cheaper with them than buying the parts from Mouser or DigiKey.

Mind you the footprint used for the SMD components can be the hand solder versions which have bigger pads if someone were so inclined to hand solder all the SMD components. I know at least a couple people who don't mind soldering 0603 components without magnification. Just like you I'm not one of those people who find it enjoyable lol.

For something with SMD components I've made a 3D printed stencil before to apply solder paste and then another 3D printed stencil to place the components. Then you just place it in an oven. I made the stencils manually in the past but I think I got an easier way to do it with Kicad that I need to investigate further.

If SMD is not your cup of tea and want a replica board then the current SE Reloaded board is the way to go.

I don't consider these two boards mutually exclusive. I'm all for options. They would both have their own benefits and downsides based on a persons wants and needs.

But, since there's no SMD version of the SE Reloaded board right now, there's only one real choice currently.

 

[trag]

By the way, I bought my Bourns (shown in my video) from Mouser, just before Mouser terminated sales of that product; but man alive! I had to pay a whopping $6.15 per chip! And although UT Source sells them now, they charge $3.76 each with a min. order of 2pcs (keep in mind you need 4pcs for the SE board), and then you have to pay then $20 in shipping fees!

If you remember my old tantalum capacitor thread on 68kmla, going back to 2007, I added the Bourns filters in 2012. I still have a bunch of them. But shipping a few at a time to folks who don't need anything else is barely worth the effort at this point. Of course, the original purpose was always to help folks get the capacitors they needed, not to make money. After 15 years, I'm kind of glad most folks have figured out how to order them for themselves now....

Anyway, I don't remember how many I have but I found about $3 each to cover my costs. The problem now days is shipping is so expensive and I'm busier or older and more tired. Not sure which. I'd probably be open to selling off the ones I don't expect to use in my lifetime in one batch.

BTW, Digikey appears to still stock them, but again, more than $6 plus shipping. Looks like they have 342 and won't be getting more. If you order 100 at a time they're $4.16. These have the L suffix, which just means they're RoHS compliant.

https://www.digikey.com/short/ppd2mf

Regardless of any of that, I think this is a wonderful project. Inventing ways to replace these old parts as they become unavailable is important.

 

[JDW]

If you remember my old tantalum capacitor thread on 68kmla, going back to 2007, I added the Bourns filters in 2012. I still have a bunch of them....

My SE Reloaded Part II video is where I solder in the 4 Bourns filters, so if you would be willing to kindly help out the community with the sale of 4 or 8pcs at a time, feel free to post a comment under that video and I will make it a pinned comment for people to perpetually see. I feel that is important, despite the existence of this amazing recreation project, because right now the matter is about one's "total cost outlay." Build time is a cost consideration too because time is money. (You could opt for "assembly" at the PCB maker, but that too costs extra money.) And since PCB makers refuse to sell a single PCB panel (they require 5pcs of any PCB minimum), you end up with 120pcs when you buy 5 panels. That doesn't mean you need to build them all, but it does produce waste, since most people probably won't sell the leftover panels, and it's a bit of wasted money too on those unused panels. Most people probably just want a pack of 4 or 8 Bourns chips and that's it. That's where your excess stock of Bourns comes in. If you can sell those, it helps people out who otherwise may not wish to embark on building the Gerber files in this project.

But at some point, when DigiKey and other sellers run dry of stock, it then becomes more than just a cost and convenience issue. It becomes an availability issue. And at that future time, this Bourns filter recreation project becomes absolutely crucial, despite the fact you'll end up with 120 chips worth (5 panels). This project will end up being the only source of the Bourns DIP chips, which are needed not only for the SE Reloaded project, but also to repair other compact Macs like the SE/30 when a Bourns ends up getting fried for some reason. As such, @alxlab deserves mountains of praise for his work on this, and for his other nifty creations too!

 

[Elemenoh]

@alxlab I was trying to order but got this error on the BOM / Pick and Place page

Do you know what might be wrong? I followed the instructions on the readme and tried starting over, but got the same result.

 

[Elemenoh]

I clicked continue which seemed to be okay. Unfortunately the resistors themselves seem to be out of stock. I couldn't find an available replacement part. If you know of one please let m know.

 

[alxlab]

Yeah looks like the resistor is out of stock,. The other U1 error can be ignored.