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Posted By

crock
on 2011-10-22
09:31:32
 Pre production Plus4 board manufacturing fault

When I acquired my C= 232, I also acquired this pre-production plus4, serial number 190, from the same source. While trying to find why my diagnostic harness caused the machine to fail to boot, I realized that this machine has a rather major manufacturing fault. You can see it clearly in the picture when you know what to look for. Bonus point for first to spot....

http://www.inchocks.co.uk/c64/190_PCB.jpg

Rob

btw, how do I have to enclose a link to make it clickable in this forum?

Posted By

TLC
on 2011-10-22
06:08:23
 Re: Pre production Plus4 board manufacturing fault

They somehow forgot about the ROM jumpers... wink Not bad... happy

Posted By

crock
on 2011-10-22
06:37:33
 Re: Pre production Plus4 board manufacturing fault

I hadn't actually noticed that!

The more interesting mistake is that the key-ways on the user port are reversed! They should be between contacts 1 & 2 and between 10 & 11. On this board they are between 2 & 3 and 11 & 12.

This means that you could (as I did with my diagnostic dongle) plug devices in upside down, sending 9v AC into all the wrong places!

Posted By

TLC
on 2011-10-22
07:14:59
 Re: Pre production Plus4 board manufacturing fault

Didn't know your diag dongle was to be plugged to the user port, I only remembered the ROM part... happy Well, that looks terrible indeed. I hope the machine sustained no damage... :o

Posted By

crock
on 2011-10-22
12:21:50
 Re: Pre production Plus4 board manufacturing fault

Well, it did actually , although the fault may have been there already. One of the drams had a column stuck high. Fortunately is was easy to trace and replace the culprit. It's 100% again now.

My diagnostic setup has loopback dongles on all the external ports. The user port specifically has checks for the 8 general i/o ports and on the RS232 RTS/CTS Rx/Tx, DCD/DSR.

See the movie here:

http://www.youtube.com/watch?v=BCw3PD5cb88

Rob

Posted By

SVS
on 2011-10-23
03:54:30
 Re: Pre production Plus4 board manufacturing fault

@crock:
>>btw, how do I have to enclose a link to make it clickable in this forum?

<*u*r*l>complete_link<*/*u*r*l> (without asterisks)



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