H4G - Mongrel SMT Edition

[Icky]

- H4G Mongrel SMT Edition

Starting a thread where @exxos and I will update on all the fixes and changes as we work on the next board H4G.

We will start with all the fixes from the patch info https://www.exxosforum.co.uk/forum/viewt ... =78&t=2335. Below is the list of all the patches and the fixes for them to start this thread off.

Holes - a few tweaks where required to holes on the board. The following pictures show the improvements and fixes.

Screenshot 2020-05-20 at 13.37.23.png (233.87 KiB) Viewed 9125 times

Screenshot 2020-05-20 at 13.48.08.png (219.33 KiB) Viewed 9125 times

Screenshot 2020-05-20 at 13.36.58.png (233.47 KiB) Viewed 9125 times

Battery - a route close to the pad was exposed with the potential to short. The route has been moved out of the way.

Before:

IMG_4715.JPG (405.41 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 14.42.56.png (110.2 KiB) Viewed 9125 times

MFP OSC - The MFP OSC was orientated vertically which obstructs mounting a floppy drive. The OSC has been laid flat.

Before:

IMG_4545.jpeg (503.01 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 16.25.15.png (423.95 KiB) Viewed 9125 times

Missing DTACK Route - There was a missing DTACK route between the CPU and Blitter.This has been added.

Before:

Capture.PNG (205.74 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 16.31.46.png (469.7 KiB) Viewed 9125 times

DMA Resistor - One of the DMA resistors was underneath the DIL socket location. This has been moved out side of the socket area.

Before:

dmares.jpeg (210.61 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 16.41.12.png (482.54 KiB) Viewed 9125 times

BGACK Pull Up - BGACK was missing a pull up. There is a spare pin on RP8 we can use.

Before:

oopsies.JPG (149.29 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 16.56.45.png (100.69 KiB) Viewed 9125 times

4MB RAM SIMM - Route was to the wrong pin so needed moving to enable the 4MB to be seen.

Before:

1.JPG (114.59 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 18.21.45.png (136.66 KiB) Viewed 9125 times

RS232 Fix - Route to Pin 20 needed to go to Pin 7 instead.

Before:

px.JPG (206.46 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 17.24.29.png (524.25 KiB) Viewed 9125 times

DAC Fix - ADC0 lines were tied to GND they need to be balanced between 5v and GND.


Before:

dacf1.JPG (358.07 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 17.34.36.png (646.5 KiB) Viewed 9125 times

DMA Issue - To get the DMA to work required a patch board. This board circuit has been included in to the H4G schematic.


Before (patch board):

IMG_5281.jpeg (173.31 KiB) Viewed 9125 times

Fixed:

Screenshot 2020-05-20 at 17.51.22.png (527.22 KiB) Viewed 9125 times

[PaulJ]

Sign me up for 2 or 3.. like the SMT construction much better, looks great.

[derkom]

I'd build another one.

[DoG]

Not SMT on the 74LS245? Or is this a WIP? All 74LSxxx chips will be SMT I hope.

[exxos]

Not SMT on the 74LS245? Or is this a WIP?

Icky hasn't posted everything yet

[Icky]

Not SMT on the 74LS245? Or is this a WIP?

WIP @DoG. You dont want to see the spaghetti its in at the moment. Will be updating pics of all the sections as they turn to SMT.

[DoG]

I thought so. DoG is happy

[Tomswork]

Sign me up for 2 boards as well.

Tom

[exxos]

I will start a new thread soon for interested parties in the new board..

[PhilC]

I will start a new thread soon for interested parties in the new board..

Sign me up cos its gonna need breaking