Re: [neonixie-l] B7971 Tubes circuit.
Anyone have an idea of what the circuit is, or should I setup better pictures. Twp giesses. given that there are 14 cathode driver transistors and current limiting resistors. It's a 2x1 multiplex, driving the tubes alternately, or (more likely), it's using them direct drive, as 7-segment readouts, with various cathodes paralleled to give the usual layout. I'm guessing it's a counter of some sort. Hard to tell without knowing what's on the other side of those octal sockets. - John -- You received this message because you are subscribed to the Google Groups neonixie-l group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] B7971 Tubes circuit.
Now more curious than ever going to take to work and take pictures to post. The problem is that the octal sockets are empty. So, I don't know what tubes would have been in them. I mis-read the auction as it said they were included (but what was meant was that the sockets were included). Basically, I wanted the tubes and the sockets, so got a fair value. Will take pics and post later. Michail In a message dated 5/24/2011 5:06:25 A.M. Pacific Daylight Time, jreh...@mac.com writes: Anyone have an idea of what the circuit is, or should I setup better pictures. Twp giesses. given that there are 14 cathode driver transistors and current limiting resistors. It's a 2x1 multiplex, driving the tubes alternately, or (more likely), it's using them direct drive, as 7-segment readouts, with various cathodes paralleled to give the usual layout. I'm guessing it's a counter of some sort. Hard to tell without knowing what's on the other side of those octal sockets. - John -- You received this message because you are subscribed to the Google Groups neonixie-l group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] B7971 Tubes circuit.
On 5/23/11 8:27 PM, micha...@aol.com wrote: I purchased this item on ebay. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersionitem=280660703999 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersionitem=280660703999 Anyone have an idea of what the circuit is, or should I setup better pictures. Michail This is clearly a one-off device, not production. Perhaps they made a few of them. The octal sockets could be connectors to cable-mounted switches used to control the display. For example, a scoreboard for a gymnasium would use remote switches to control the score. You would have to trace out the schematic diagram to know for sure what it does, and even then, there will be some guessing. It would be very helpful to know what ICs are installed on the board. I assume that the two ICs feeding the transistors are 7448 or similar BCD to 7 segment decoders. There are 5 more ICs, which could be latches, counters or some combination of these. Can you take a clear photo of the top of the board, showing all the ICs? Or at least make a list of the IC numbers? They'll all start with 74. -- David Forbes, Tucson AZ -- You received this message because you are subscribed to the Google Groups neonixie-l group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] B7971 Tubes circuit.
Hello, Only took a few temp photos... _http://michail.selfip.com/temp/_ (http://michail.selfip.com/temp/) Real fast - without powering up and taking apart wire loom 3 octal sockets. Pin 1 on each tied together and go to input or output side of 7805 (can't tell since using same color) Pin 8 on each tied together and go to ground Pin 7 on each tied together and go to a transistor other pins go to various spots connected to chips. Chips 2x 7448 1x 74185 1x 7410 1x 7400 2x 7483 So, appears the guess about a rotary dial for score is looking close. Michail In a message dated 5/24/2011 9:56:54 A.M. Pacific Daylight Time, dfor...@dakotacom.net writes: On 5/23/11 8:27 PM, micha...@aol.com wrote: I purchased this item on ebay. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersionitem=280660703999 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItemVersionitem=280660703999 Anyone have an idea of what the circuit is, or should I setup better pictures. Michail This is clearly a one-off device, not production. Perhaps they made a few of them. The octal sockets could be connectors to cable-mounted switches used to control the display. For example, a scoreboard for a gymnasium would use remote switches to control the score. You would have to trace out the schematic diagram to know for sure what it does, and even then, there will be some guessing. It would be very helpful to know what ICs are installed on the board. I assume that the two ICs feeding the transistors are 7448 or similar BCD to 7 segment decoders. There are 5 more ICs, which could be latches, counters or some combination of these. Can you take a clear photo of the top of the board, showing all the ICs? Or at least make a list of the IC numbers? They'll all start with 74. -- David Forbes, Tucson AZ -- You received this message because you are subscribed to the Google Groups neonixie-l group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB. -- You received this message because you are subscribed to the Google Groups neonixie-l group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
Re: [neonixie-l] B7971 Tubes circuit.
On 5/24/11 6:49 PM, micha...@aol.com wrote: Hello, Only took a few temp photos... http://michail.selfip.com/temp/ Real fast - without powering up and taking apart wire loom 3 octal sockets. Pin 1 on each tied together and go to input or output side of 7805 (can't tell since using same color) Pin 8 on each tied together and go to ground Pin 7 on each tied together and go to a transistor other pins go to various spots connected to chips. Chips 2x 7448 1x 74185 1x 7410 1x 7400 2x 7483 So, appears the guess about a rotary dial for score is looking close. Michail I think it adds three binary numbers from the three octal connectors, and displays the sum as a single decimal number. -- David Forbes, Tucson AZ -- You received this message because you are subscribed to the Google Groups neonixie-l group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
