Yet another ROM adapter

Discussions about Sinclair ZX80 and ZX81 Hardware
McKlaud
Posts: 36
Joined: Tue Dec 19, 2017 9:02 pm
Location: St Albans, UK

Re: Yet another ROM adapter

Post by McKlaud » Fri Dec 22, 2017 3:44 pm

Paul,

Why buying faulty ICs? I can send you a bunch of faulty EPROMs and Z80 for your surgical procedure if you wish. Only postage you would pay. :lol:
Claudius
----------

User avatar
Paul
Posts: 901
Joined: Thu May 27, 2010 7:15 am
Location: Germanys west end

Re: Yet another ROM adapter

Post by Paul » Fri Dec 22, 2017 4:41 pm

McKlaud wrote:
Fri Dec 22, 2017 3:44 pm
Paul,

Why buying faulty ICs? I can send you a bunch of faulty EPROMs and Z80 for your surgical procedure if you wish. Only postage you would pay. :lol:
;)
In theory, there is no difference between theory and practice. But, in practice, there is.

User avatar
sirmorris
Posts: 2734
Joined: Thu May 08, 2008 4:45 pm
Location: oxon, uk

Re: Yet another ROM adapter

Post by sirmorris » Fri Dec 22, 2017 4:46 pm

McKlaud wrote:
Fri Dec 22, 2017 3:44 pm
Why buying faulty ICs?
It worked for Sir Clive hahaha :lol:
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

User avatar
mooredan
Posts: 20
Joined: Sat Nov 18, 2017 3:47 pm
Location: Portland, Oregon, USA
Contact:

Re: Yet another ROM adapter

Post by mooredan » Sat Dec 23, 2017 12:55 am

McKlaud wrote:
Fri Dec 22, 2017 7:35 am
...

Coming back to your adapter, could you use all components in SMD packages including both capacitors in next revision of the board? MLCC 4.7uF/10V is available in 805 size. In KiCAD you can also find components' footprint for hand soldering. Pads are longer and they are really handy. Yes, they require more space on the PCB but it is not the case on your board.
Thanks for the suggestion. I originally started laying out the board with SMD's for the two top-side caps, but then decided against it. Although I didn't use my reflow oven to assemble my prototype, I thought that I might when designing it. SMD's on both sides would need two stencils (if I want to be efficient about it) and give the board two passes in the oven, (actually I don't know if the socket and jumpers would survive), but I had the through-hole socket as it was and I was going to be faster with soldering through-hole any way. I went with the SMD resistors just to keep the profile low as I do plan on soldering it directly to the zx81 board, and being on the underside was convenient.
Dan Moore
Portland, Oregon, USA

McKlaud
Posts: 36
Joined: Tue Dec 19, 2017 9:02 pm
Location: St Albans, UK

Re: Yet another ROM adapter

Post by McKlaud » Sat Dec 23, 2017 1:05 am

I used your ideas and made the other PCB layout shown on the picture below. I used THT components only. All reesistors to be installed on the other side of the PCB underneath the EPROM chip. Placing THT components is feasible and the board is still small. Having SMDs in 0805 packing do not make the board smaller anyway.

Image
Claudius
----------

User avatar
mooredan
Posts: 20
Joined: Sat Nov 18, 2017 3:47 pm
Location: Portland, Oregon, USA
Contact:

Re: Yet another ROM adapter

Post by mooredan » Sat Dec 23, 2017 2:22 am

There ya go. ...looks great.
Dan Moore
Portland, Oregon, USA

McKlaud
Posts: 36
Joined: Tue Dec 19, 2017 9:02 pm
Location: St Albans, UK

Re: Yet another ROM adapter

Post by McKlaud » Sat Jan 06, 2018 8:15 pm

My mini boards arrived and work well.

The prototype in flesh
Image

Image

moordean, thanks for the idea :)
Claudius
----------

Post Reply

Who is online

Users browsing this forum: Dim_75 and 3 guests