Nice design. I also just finished my design and ordered PCBs from JLCPCB. It's called neat8701 as it is similar design style as neatPLA https://github.com/1c3d1v3r/neatPLA It has all parts on the bottom side. You can use an oscillator soldered to the PCB or original crystal on C64 motherboard. NTSC/PAL selection is done with a solder bridge. I solved the IC width problem by cutting the IC pins a little bit shorter with flush cut pliers. I made a custom PCB footprint for it. The PCB pins are soldered from the top side. The through hole pads have smaller diameter annular ring on the bottom side to make more room for the IC. PCB rendered images: https://imgur.com/a/zcvUqkw The configuration is "45-55% duty cycle, lowest jitter". I'll compare it to the "no duty cycle restriction, lowest jitter" configuration which many other uses. I'll change the connection if necessary. Later on the design will be shared at github. -Pasi On Fri, 10 Jul 2020 at 21:21, Jeffrey Birt <birt_j_at_soigeneris.com> wrote: > I have been working on a MOS 8701 clock chip replacement that is just a > bit bigger than the original so it will fit into a C128 with the RF shield > cover in place. > > The design is based on Frank IZ8DWF's design from one of his videos. The > PCB size is about 0.5"x0.9" with the holes on 0.4" centers. This was needed > to make room for the SSOP28 clock chip. > > The 0.4" spacing required making a fixture to custom bend some leads into > a 'Z' shape. And another fixture is used to align the leads for soldering. > To make it even more fun the resistors and caps are 0603 size which is > about as small as I care to do without a proper microscope. I built the > first board this morning and it works!! It takes a fair amount of time to > build one of them, and you need the special fixtures for the leads, but it > was an interesting challenge. > > This version of the PCB uses cut pads to configure NTSC or PAL. I have a > new design that should do this automagically. I should have some of those > PCBs in a few weeks for testing. > > > > _at_IZ8DWF – Frank when I am able to confirm that PAL works, I will send you > some completed units, gratis. > > Links to images > > > > https://1drv.ms/u/s!AtH4vpaZnzX7kvswntJpVdEm6W-OrQ?e=4wnmac > https://1drv.ms/u/s!AtH4vpaZnzX7kvsts_rsv_eTHoKL7w?e=TlqTnX > https://1drv.ms/u/s!AtH4vpaZnzX7kvsuRF1lVXL5UNJLgA?e=NjEhZa > > Jeff Birt (Hey Birt!) >Received on 2020-07-10 22:00:03
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