| Posted By
icbrkr
on 2014-01-08
22:05:26
|  Broke my C16
I was in the process of upgrading my C16 from 16K to 64K and I did something I shouldn't have - I got into a hurry. I ended up ripping a few of the traces off the motherboard which of course is bad. I got the new sockets in, and I added new wires to where the traces should have gone - but of course, it can't be that easy, it doesn't work. When I fire her up, I get random characters on the screen. I figure that's not a totally bad sign, that means it at least detects the memory enough to fire up.
I read over the schematics, and most of the stuff seems pretty straightforward on U5/6 most pins go from one chip to another onto the same pins. I'm a bit confused on pin 17 - where does this go? And pins 15, etc, the ones marked D0, 1, etc - do they all connect somewhere?
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Posted By
gerliczer
on 2014-01-09
09:16:33
| Re: Broke my C16
Sad news. If I were in your shoes I'd try to buy another one until I could. AFAIK they are cheap.
There is no such thing in these computers as detecting memory, at least not that I know. These old irons would try to start up and run without RAM and I think they would manage doing so but without any meaningful result from the viewpoint of the user.
Regarding the question about the schematics I don't really understand what you mean by "on U5/6 most pins go from one chip to another onto the same pins". There is no connection between U5 and U6. Those pins connect to the address/control bus of the system (I took a quick glance on the schematics over at zimmers.net and it is really confusing a bit). Pins 2, 3, 15 and 17 connect to the data bus of the system. One chip is the lower 4 bits of one byte of the memory, the other is the upper half.
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Posted By
icbrkr
on 2014-01-09
10:39:05
| Re: Broke my C16
Actually, got it work this morning.
on U5 and U6 (if you look carefully), most of the pins DO connect to each other.. pin 10 goes to pin 10, pin 11 goes to pin 11, etc, on U5 and U6. It doesn't show a connection, but it does have a number next to them to let you know how they connect.
Last night I remembered I had a C116 in a drawer (doesn't everyone?). Since they're mostly the same motherboard, I brought out the continuity checker, and found that pin 8 is supposed to connect to one of the ROM chips. On my 16, it wasn't connected. I connected it, and success!
Now I wait for the 64K chips in the mail to finish modding this 
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