exxos blog - random goings on

[PhilC]

@exxos cool as my two Megas need some one HD loving.

[exxos]

I have been also looking at SMT pasing machines.. This one seems to be that the only comparable solution out there..

https://www.voltera.io/store/





The problem with that is paste generally goes off rather quickly,I would hope it would use generic paste but it will be difficult to tell without actually trying it. It also only has a small 10x12cm print area.. Which would probably be okay for most of my stuff.. It also accepts PCB files, so other than setting up the hardware, it is pretty much print and go.

On the flip side, there is the through-hole component machine hours looking at in this post.. https://www.exxosforum.co.uk/forum/viewt ... 780#p38967 as pretty much everything I make uses header pins, that alone would save some time, but because a lot of boards are mixed through-hole and SMT.. I would have to do the SMT myself, or send it away to be done which kind of defeats the object in saving time and costs..

Also the through-hole machine uses some odd external programmer, I have asked more information about this, as if I have to manually set up the solder location one at a time, that could be extremely time-consuming, which then defeats the object of saving time in having the machine again.

Some SMT parts I could get assembled at JLC.. Which would help in some cases if their only generic parts, but when it comes down to things like the video DAC etc as they would have the same problem of assembling them here.

In terms of assembling the H4, having the bulk of the SMT parts done with the PCB would be half the battle, the through-hole machine I could set up to solder in all the sockets etc.. While it would be a great time saver, it also is relevant to how many of the boards will actually sell in order to pay for the machine in the first place.

In terms of SMT pasting machine, things like my Simms take a lot of time and pasting up.. Is probably one of the things I have sold the most of, simply because there are 4 simms per pack. So just 10 sets is 40 simms to paste.

I think it really boils down to I need both machines but my pockets are just not that deep When he gets onto like £8,000+ I really would have to be selling a lot of boards to get my money back on it all.

It would be easier if I sold thousands of one single item, once set up for mass production, the costs would come right down and it would be worthwhile having a machine. But with a lot of different items with near zero sales, I can foresee the spending a lot of time setting things up where it could possibly be quicker and easier to go on as I am currently doing now.

The only other possibility is try set up a sideline business the doing some low volume assembly work And get the money back that way.. Problem being dealing with people takes a phenomenal amount of time that I don't have either.

[exxos]

In light of through-hole assembly, I started looking at the STE DUALTOS boards which were all through-hole parts...

STE_DUAL_TOS_PCB.jpg (158.57 KiB) Viewed 4414 times

A few people complained that it needed to be a bit longer to miss the floppy drive ( even though it fitted perfectly well my machines ) So I took that board and made it a little longer and have been playing around with the autorouter..

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The router makes no sense at all... With one design I had forgotten to link up the ground plane fill, so it was routing the ground wires even though we did not have to. The thing is it then used 40 vias MORE when the ground plane was activated... You would think it would be more logical that it would use less because it had to route the ground tracks before... But nope, we are working with reverse logic here and it greatly increased the amount used

So I had a thought to turn off all layers and do them one at a time individually with the autorouter. The routing is not great, but now uses zero Via's. But really other than really smoothing out a few right angle tracks there is nothing really wrong with it anyway.

The idea for these is that I could get the 2SMT parts done at JLC with the PCB's, and ( assuming I had a assembly machine) assemble the header pins and socket here myself.

I went back to this particular design because the last one I did Inc a UBE chip and a SMT socket. Both of which would cause problems in assembly otherwise. While the UBE chip is a good idea for switching TOS.. I just get emails constantly of issues because of people having bad reset circuits in their machine I also don't want to fit the chips manually myself, or have the hassle of programming them or sending them off to be assembled etc

I think realistically the UBE chip should be on its own widget board which it was actually originally but never produced.. Or maybe s small dedicated board to also replace the reset circuit in the STE with the reset chip used in the H4. The may be a project for @ube

[stephen_usher]

That's a nice solder paste printer, but is is any better than having a mask?

As for the UBE switch, I think some people are too picky. The worst I've had to do it hit the reset switch after switching on when the machine hasn't been turned on for a while. Not exactly the end of the world and worth the minor hassle to be able to switch TOS without an extra hole in the case.

[exxos]

That's a nice solder paste printer, but is is any better than having a mask?

You mean a stencil ? they can be quite fiddly to use without a proper setup rig.. more work to paste things manually.

[stephen_usher]

That's a nice solder paste printer, but is is any better than having a mask?

You mean a stencil ? they can be quite fiddly to use without a proper setup rig.. more work to paste things manually.

Yeah. I assumed you'd have to use a jig to hold the PCB in the correct place.

[exxos]

Yeah. I assumed you'd have to use a jig to hold the PCB in the correct place.

Only have one for the simms... I would have to design and print a jig out for multiple pcbs would take probably a year I just mostly use clamps to get by

[exxos]

I got distracted again, and started designing a new STE reset circuit with the UBE TOS SELECT switch on it...

Capture.JPG (60.33 KiB) Viewed 4383 times

2.JPG (96.5 KiB) Viewed 4381 times

[ube]

On it. (More or less). Could you add a 5V pin as well? Make it a four pin header with one blank (5-blank-gnd-sel) so people wont complain about soldering a physical switch the wrong way.

Edit: read it all. Oh well. ¯\_(ツ)_/¯

[exxos]

On it. (More or less). Could you add a 5V pin as well? Make it a four pin header with one blank (5-blank-gnd-sel) so people wont complain about soldering a physical switch the wrong way.

Lost me.. .Are you talking about the widget as was done on the earlier ROM boards ? I've moved the UBE ROM chip to the 555 reset circuit on the STE.. long thread about it all above somewhere...