My supply was an old computer supply, giving me 3.3 5.15 and 12 volts, also all these only in negative "outputs". I did what you said and set up a 7805. It gave me a steady 5.04 volts.
I did full testings of the chip. I found out that the first two bits are stuck on 01. So instead of 0000 I get 0100. This means I only got outputs 4, 5, 6, 7, and so on repeating itself (instead of 0 1 2 3 4 5 6 7 8 9 its 4, 5, 6, 7, 4, 5, 6, 7, 4, 5,... even for the last 6 outputs that were supposed to all give 0) Any way to unstuck these, or are they done? Thanks people On Feb 10, 8:53 am, Cobra007 <mic...@xiac.com> wrote: > I would recommend to use a switch mode 5V regulator, no need to worry > about dissipated heat. > > For low current power supplies I still use zener diodes, works very > well if certain applications and no need to worry about voltage drops. > > Judging from your data (17mA & 300ohm), your power supply is then > about 10V. A series resistor to go from 10V down to 5V TTL really is > an unusual solution. You can never guarantee that the current will be > 17mA in all situations, so the voltage may vary between 3 and 8 for > example, frying your chips in the mean time. > > Michel > > On Feb 10, 6:10 pm, "Tidak Ada" <offl...@zeelandnet.nl> wrote: > > > > > > > > > If you use a 7805 as voltage stabilizer, consider these IC's need an > > overvoltage of at least 3V at the input. The show an voltage drop of that > > 3V. Usually a transformer with an output of 8 to 9 volts AC is advised (This > > results in a raw DS of 1.4 × 8 = 11.2 V. So you are safe for line and load > > dips. Adequate cooling of the 7800 is required ! > > > eric > > > -----Original Message----- > > From: neonixie-l@googlegroups.com [mailto:neonixie-l@googlegroups.com] On > > > Behalf Of dr pepper > > Sent: vrijdag 10 februari 2012 7:00 > > To: neonixie-l > > Subject: [neonixie-l] Re: Burned K155ID1 chips? > > > 74 ttl as mentioned really needs a 5v regulated supply, the 7805 is > > important. > > Also a ceramic decoupling capacitor accross each chip supply pins is a good > > idea, I've had similar issues with 74 devices, when the transistors change > > state within the device there is a 'rush through', sort of a temporary short > > across the 5v, this can deck the supply at the chip if there is resistance > > or incductance in the supply to it, which there allways is and cause a reset > > or screwup. > > > It does sound like the chips are fried though. > > > On 10 Feb, 04:56, micha...@aol.com wrote: > > > Does 0101 give a 5 as well? > > > > Was wondering if 0100 is stuck. > > > > Does it count...... > > > 4 5 6 7 4 5 6 7 8 9 4 > > > instead of > > > 0 1 2 3 4 5 6 7 8 9 0 > > > > Michail > > > > In a message dated 2/9/2012 7:42:23 P.M. Pacific Standard Time, > > > > imba.a...@gmail.com writes: > > > > These were the results; input 0001 gives 5 instead of 1, and 0011 > > > output 7 instead of 3, etc. > > > -- > > 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 > > athttp://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.
