On Thu, Aug 6, 2015 at 8:29 PM, Paul Bower paul@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:Yup it was me using the wrong pad as ground - all working fine and the NAND/AND module is now sat next to the XOR/OR that I completed around 13 years ago
Gratuitous photos maybe in a few days :-)CheersPaulOn 4 Aug 2015, at 21:49, Paul Bower paul@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:Sage advice :-)
I checked the pins on the 4093 even though I ‘knew’ they would be fine - hey presto I think I figured it outI originally used the MTA156 connector for one board and for the second board used the auxiliary pins to piggyback the two (I didn’t do this on my other module, i wired bits of 6A mains cable directly into the second MTA connections)This time around assumed the two middle pads were ground (this is the set of pads right at the end of the board next to the MTA156 pads) - and chose the wrong one - i chose the one that was connected to nothingMy eyes are tired tonight, so will rewire the full 4x AND / 4x NAND modules and report back, but I think we’re sortedThanks for all the help :-)Next up - Gate Sequencer with 2 extra switch rows - populated boards sat in a box since 2003 and I just got a very good deal on flat toggle switches from Musikding (and i’ve designed a full 5U wide panel)CheersPaulIn that case, check it is getting the correct voltage to its power pins first :)On Tue, Aug 4, 2015 at 12:15 AM, Paul Bower paul@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:I was afraid you would say that - i got into the habit of soldering ICs direct to boards
I’ll pop in a replacement chip (maybe with an holder this time)Swap the two CMOS chips between your units, and see if the fault follows the chip, or says with the board.--On Mon, Aug 3, 2015 at 11:23 PM, Paul Bower paul@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:I thought you were all ignoring me, then I realised my Yahoo settings weren’t correct and the Yahoo notices were going to spam :-)
Anyways…I’m still plugging away at this one, and got a little DSO Nano so I can actually measure things reasonably properly
I separated out the two boards and tested each in isolation - the AND board is fine
The NAND is a different matter (and clearly whatever it was doing was interfering with the other board), I measured the following:
In 1 off / In 2 off =3D LED on / Output 1 is 6v
In 1 off / In 2 on =3D LED on / Output 1 is 9v
In 1 on / In 2 on =3D LED on / Output 1 is 11v
The output of the LM324 feeding into the 4093 (I’m using an HCF4093BE) looks to be okay - so I’m wondering if its the 4093 that is the issue
Any hints before I rip it out and try a different 4093 or maybe a 4011 ?
Cheers
PaulAs long as you are happy with having to plug a signal into each input to get a response, no, you don't need any switched connection on the jacks. As that is how a NAND works, you should be fine.
The only possible reason to use a switched jack to positive (via a 1k resistor) would be if you wanted it to work as an inverter when you have only one signal patched into it.
Or, you could disconnect the 100k pulldown on each input from 0V, and connect them to 15V instead. No switched jacks would be needed that way.
Ken
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Message
Re: First Issue CGS39 Quad Logic Board
2015-08-06 by Ken Stone
Good stuff :)