rubber_jonnie wrote: ↑
Wed Feb 21, 2018 5:10 pm
Chris, just how easy would it be to make a on piece RTC board based on our re-engineered FGMCII? I know we have the two piece model, which is most excellent as a plug in cart, and we have the smaller board that can be fitted internally if you wish.
But what about a one piece board as per the original? Would it be any cheaper to make it a single board?
I did design it originally.. But, Basically if I did a direct clone as well, I would have had to stock 2 lots of the RTC IC's, and at like £12 a go, I didn't want to invest in like 10 kits of internal and external. So I went for just doing the PCB and re-using the RTC internal kits on the cart pcb. From my point of view it was a good move as the RTC stuff just doesn't seem popular.
So yes, a possibly a RTC pcb could be produced like the original.. Though It wouldn't be much smaller than it is now (unless the through-port was removed) and I got it as small as I could already.
I also opted for 4 layers to have a solid 5V and 0V between the "in and out" side of the cart pcb. I couldn't actually route it on 2 layers either and I had a few attempts at it, just wasn't happy with how it was ending up. The original cart is pretty clever with the routing for just 2 layers, but I wasn't to happy with the thin tracks across the board anyway. I was thinking of expansion stuff added after the cart should have a solid power rail (Why I opted for 100uF ceramic also). But in doing that, doubled the PCB costs, but I want to make something "solid" as didn't want to risk voltage drops and grounding issues on anything connected on the through-port.
With all that in mind, PCB wise it wouldn't have made much difference to have the RTC IC built on the PCB or not. So it was down to costs really with the thought of me selling the kits. Though , as you know, nobody was really interested in the cart and doing small runs of basically 3 just isn't cost effective. Would need to do a run of more like 100 to get the price per pcb down to something sane, but again, I don't think they would sell anyway. Even if I just produced the PCB's on their own its still a huge outlay/risk on my part.
Ultimately the falcon RTC boards will be used as optional add ons for my boosters.. Its not a external solution, but I think overall people want a neat internal solution.. I don't think people are that impressed with the small RTC board I (we) did already. So IMO I think its just a dead end project. If loads of people wanted a simple external cart pcb, then I could produce it yes, but for me, I think investing the time & cash into other projects is a better choice.