You might get what looks like a good solder connection to each pin of the R-net, but the possibility exists that, unless the pin can be contacted directly by the tip of your soldering iron, it may not get hot enough to actually have solder flow around it properly. The surface of the pad may look good, but inside the plated-through-hole, you may have a cold solder joint that could be troublesome in the future. I think I’ll forgo the SIP network at this point and make discreet SIP R-nets. A little more work at the outset, but I’ll be sure the soldering is good.
Bob Bell
From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of Jeff Galinat
Sent: Tuesday, December 23, 2014 10:18 AM
To: n8vem...@googlegroups.com
Subject: Re: [N8VEM-S100:5885] Re: S-100 8-slot Backplane Version 2 Questions
Hi Josh,
As you surmised, the additional components described below are for the active bus termination setup. As noted in the previous messages, some of the component leads such as IC socket & SIP resistors are too short to protrude through the other side of the board. While this is far from ideal, I didn't think it was a show stopper since all the holes are plated through. In my case the tip of the components was visible but not protruding so I just filled the pad with solder which provided the necessary continuity. Again, not ideal but my board worked out fine.
Bob pointed out a problem with the fuses that I was not aware of in that they aren't really protecting anything but the LEDs. I have another blank board so I ohm'ed out the power input connector to the bus traces and there is continuity with no fuses installed. I followed the trace visually and just as Bob said, they go right to the bus.. I am glad that I am a little compulsive and also externally fused the power leads as the on board polyfuses could just be replaced with wire. Regarding Q1 I just checked the orientation and it matches the silkscreen but I this this is an earlier board so I can't speak about the V2 boards. The reference voltage adjusted fine and it seems to be working properly so I have to assume that Q1 is installed correctly on my board.
On 12/23/2014 9:39 AM, Crusty OMO wrote:
Hi Bob,
I'll be building one of these boards soon. Thanks for all your notes regarding your build. I'll likely go with discrete resistors. I haven't looked at any plans, I just thought this was a plain 8 slot board. Are all these extra parts to terminate the S-100 bus? F1 sounds like a fuse? There are fuses that look like 1/4W resistors and some even smaller, SMT.
Cheers,
Josh
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