Thread: Ortonview PCB
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Old 24th Jul 2021, 8:16 pm   #65
Slothie
Octode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,287
Default Re: Ortonview PCB

Well, some initial results. I programmed a chip with firmware #692, fitted the address buffers and jumpered the lower 8 address lines to the data lines. The results are a bit smeary, I'm convinced this is the phono cable I am using - I didn't bother to buy one because I knew I had one in a box of miscellanea that I had, and when I got it out I discovered it was a M-F stereo cable rather than the needed mono M-M. I chopped off the female connectors and joined the 2 stereo leads to make a mono and in the process discovered it was unscreened and made of tiny unsolderable aluminium wires so popular in the far east. Its also way too long, so I am 90% certain that is where the problem is. Another possibility is I fried the transistor a little too much as I was having trouble soldering it without shorting it due to the microscopic footprint I seem to have chosen for it.
However, the display is rock solid aside from the smearing and the buffers are apparently working enough to switch on at the right time, so tomorrow is testing the on-board memory and connecting it to the MK14 and running some of the test programs I think Tim posted to the original thread.

I've definitely overdone the regulator, the board pulls hardly any current and would probably have been OK to use a little TO92 regulator, or even pull from the MK14 (which is an option!).
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