SC130, Z180 Motherboard

[Steve Cousins]

I have, today, sold my 100th SC126 Z180 motherboard kit and coincidentally have just listed another Z180 motherboard (SC130) on Tindie.

SC130 is a smaller, cheaper, Z180 system. It is aimed at new users or anyone primarily interested in running RomWBW and CP/M software. It is expandable but has fewer features than SC126.

I'm offering it on Tindie as a complete kit, including the USB cable, FTDI adapter, and micro SD card adapter, for $49 plus shipping. The only extras required are an SD card and a serial terminal (ie. PC with terminal software).

Wayne has kindly produced a version of RomWBW for SC130. Thanks Wayne.

Steve

[Karl Albert Brokstad]

Congratulations Steve

100kits in how many months? 3-4?

What's the difference between SC126 and SC130? As far as I can judge, only one 512kROM, no RTC, fewer bus connectors.

Karl

[Steve Cousins]

Karl,

Less than 3 months since I started selling SC126 on Tindie. That works out to be almost exactly 1 kit per day. No wonder I'm getting bored of putting the kits together!

The differences are:

Only one SPI port (not 2)

No I2C port

No output LED port (8 LEDs)

No realtime clock and battery

Only 40 pin bus sockets (not 80 pin)

Only 2 bus sockets (not 3)

Only one ROM socket (not 2)

Steve

[Karl Albert Brokstad]

The missing features are not vital for general use and can be added later as modules.

It is still a very good value compared.

Karl

[Steve Cousins]

I think that is the cheapest I could make a CP/M system with a genuine Z80 family processor. Annoyingly the RAM chip is really expensive.

My thinking is to supply a complete kit suitable for people new to retro computing or with only very modest soldering experience or for anyone who is more interested in running RomWBW and CP/M software than playing with hardware.

Steve

[Alan Cox]

On Wednesday, 2 October 2019 20:26:52 UTC+1, Steve Cousins wrote:

Karl,

Less than 3 months since I started selling SC126 on Tindie. That works out to be almost exactly 1 kit per day. No wonder I'm getting bored of putting the kits together!

The differences are:

Only one SPI port (not 2)

No I2C port

No output LED port (8 LEDs)

No realtime clock and battery

Only 40 pin bus sockets (not 80 pin)

Only 2 bus sockets (not 3)

Only one ROM socket (not 2)

And the 0x0C port is write only so presumably works fine if you have an RTC card as well. I assume that is the cunning plan behind it - keep compatible and allow for an RTC ?

Alan

[Steve Cousins]

Hi Alan,

Yes, that is indeed the cunning plan.

If you add SC129 digital I/O at address 0x0D you get SC126's LED port.

If you add a real-time clock module at address 0x0C you get SC126's RTC. One possible problem though: The RC2014 RTC module does not have ideal address decoding so writing to the LED port at 0x0D or the status LED at 0x0E could, in theory, upset the RTC. I don't have one to try. I may make a module with RTC and I2C to better match SC129's hardware.

Compatibility with SC126 is also why SC130's status LED uses a different address to SPI enable.

Steve

[TonyD]

Hi Steve

Congratulations on selling 100 kits, great news and just shows there's a very active community out there

Tony

[Colin MacArthur]

GREAT looking board...

Between designing new boards & building kits, when do you sleep? LOL

CM

[Steve Cousins]

Thanks Tony.

Spencer has sold over 2000 systems I believe. I think I've sold about 150 systems in total. Add in systems from other people (LiNC80, Z80 Membership card, etc). Is that grand total surprisingly big??? In some ways, yes, it is quite a lot of retro systems. On the other hand, there are billions of people on the planet and not all of them have got one... yet :) Seriously though, a few thousand in the whole world is a very small percentage. I'm coming to the conclusion that there are still many more potential retro community members. Perhaps we have only seen the tip of this iceberg. Time will tell.

Steve

[Steve Cousins]

Colin, you may have spotted the problem with my diversion into PCB design and now kits. It is taking up a lot of time to source parts, put together kits, and package them up for the post. I seem to have less and less time available for new projects :-(

[Bill Shen]

Steve,
Congratulation on selling over 150 boards of your design.  I admire your focus and stamina for bring retrocomputing to more people.  I myself find selling products hard work and do not have the required stamina at my age.  However, I am interested in the retro market place and intrigued by why Zx80 (as well as 680x0) can sell at higher price relative to, say, Arduino or raspberry pi.  To satisfy my curiosity, I do sell one of my designs on US eBay once a week in auction format starting from 99 cents.  I find the bidding quite active with new buyers show up below price level of $50.  I think the subject of selling in retrocomputer market is an interesting, if somewhat delicate topic.  I didn't want to get into it in RC2014-Z80 forum for fear of ruining Spencer's audience, but perhaps this forum is a good place to discuss the marketing aspect of retrocomputing.
  Bill

[Steve Cousins]

Thanks Bill. Yes, selling kits can be quite a lot of work.

I think this forum is a very suitable place to discuss selling and pricing. One of the goals of this group was to avoid commercial control and thus be free to discuss such issues. I'm very happy to discuss my pricing. I don't consider it a "delicate topic". In fact, I'm curious to know what members of this group think of my prices. I'll start a topic to discuss this.

Steve

[Richard Lewis]

There is a review on Hackaday of Spencer's new board: The RC2014 Micro the comments were interesting, Especially the one about the saturation of RC2014 like boards on Tindie.

[Karl Albert Brokstad]

Hi All

I am pleased Spencer is getting publicity, and he is selling and is able to make a living of his kits.

I don't agree that there is a saturation of RC2014 kits, merely a lack of competition.

As I tried to communicate earlier, users make a RC2014 kit, play with it and then moves on.

The RC2014 micro is not evolution, just a downscaled mini.

I do also sell kits at Tindie, not to compete with Spencer or earn money, but mainly to supply a niche market helping others, like the "repair kit". I have actively avoided offering products which could potentially sell in high quantities.

We should credit Spencer for making the 40pin bus and the modular system.

But we should not forget others who has contributed significantly to the RC2014 ecosystem.

Hardware: Grant Searle, Sergey Kiselev and Scott Baker

Software: Grant Searle, Wayne Warthen and Steve Cousins

Plus many others who has contributed.

It should not be only one person's privilege to sell these kits.

Karl

[Alan Cox]

I've mostly put the kicad files up on hackaday. I also don't really have time to get into the selling stuff side of it.

I'm building boards to fit my random desires and curiosity so most of the are probably fairly obscure. Twelve slot backplanes are definitely too small though.

Alan

[Tom Szolyga]

I finished building new SC130 and SC129 boards.  They work great!  On the SC129, I put the resistor networks connect to the LEDs in sockets.  In this way, I can remove the LED loads from a device driving the input port.

Great job Steve!

Tom

[Karl Albert Brokstad]

Tom

That's a clever solution.

Karl

[Steve Cousins]

Thanks Tom,

Good to see the design works with ALS chips.

I agree with Karl, the use of sockets for the resistor networks of SC129 is a very good idea. I did consider a buffer chip on the input port to avoid the LED load on the input signals but didn't want to make the design any more complex than necessary.

Steve

[gary phillips]

Hey Steve, your SC130 is up-n-running - excellent computer and super value ($56 shipped to US)!  Everything was included in the kit, high quality PCB, and even included USB/serial and SD cards.  It also came with a robust software suite in ROM.  What a pleasure to build and only took about 2 or 3 hours for me and my grandson.  I was a systems engineer at Cromemco back in the late '70's, but haven't touched Z80s much since then.  It's so nice to work with a computer you can build and fully understand.  I wire wrapped my first 2 systems back in the 70's from scratch; an Intel 4040 (4 bit), and a 6502.  Kudos my friend!

[Kurt Pieper]

Hello Steve,
I have been using the SC130 board for a few days.

Very good kit description and documentation favored the completion.

Since I started my Z80 time with Kaypro 4/84, I was able to familiarize myself quickly with the handling.

I say it is a board that is very suitable for beginners.

I am a hobby user and have been dealing with (6802,6502, Z80,8051,80535) systems since 1977.

Congratulations on this board.

Kurt Pieper

(Google help me)

[Pellatonian]

Here's another strong recommendation for the SC130 board. I have put together SC126, SC130 and SC131 and the SC130 was my favourite. Totally simple to build and easy to integrate into a small case, plus a reasonable price.

My 'workshop' (ie: spare bedroom) is getting a bit cluttered with cased systems, so something that has some expandability but doesn't take up a lot of room is very welcome.

Steve W.