I made a small board for my personal use to power a CBM 710 from a single 12v power supply +12v from regulater power supply -12v from ICL7660A +5v from polulu 5v regulator 50 or 60 Hz via an avr tiny 50 or 60Hz On 13/04/2018 21:04, Micah Bly wrote: > Hi All, > > I am trying to get a CBM 710 into working shape. I recently acquired > this from a collector, and my understanding is that is has never been > up and running, it was incomplete from the start. There were a few > missing chips and ROMs, but I think I'm basically down to the last > part: new PSU. > > I am the US, the machine is from Germany. 240V (or maybe it's 220V) > 50Hz vs 120V and 60Hz. > > I have enlisted the help of a long-time Commodore technician (I don't > mean he worked for Commodore, I mean he has been repairing them for > 20+ years and has his own shop still). I am entirely useless when it > comes to anything more than the most basic circuit. > > I have been reading through a few relevant historical posts on CBM > hackers, and looking through other stuff that Google reveals. So far, > we have assembled the following: > - ELM440 frequency generator. > https://www.elmelectronics.com/ic/elm440/ > - NTSC color burst crystal > - Mean Well RT-125B power supply. > http://www.meanwell.com/productPdf.aspx?i=491 > > The PSU seems like it should be fine for the power side of thing, but > could someone help us with designing a circuit for the timing? I > showed this diagram to the gentleman helping me, and he is scratching > his head pretty furiously about it. > http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/b/cbm700-ceag-PSU.jpg > > My goal here, aside from getting the CBM II back up and running, is to > document it in case somebody else wants to do something similar in the > future. I don't have a web site, so I am using a blog, here: > http://www.vintageisthenewold.com/not-your-daddys-128-retrochallenge-2018-04-update-1/ > > Thanks, > > Micah >Received on 2018-04-13 23:02:04
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