On Thu, 22 Feb 2018 07:00:54 -0500 ew via time-nuts <time-nuts@febo.com> wrote:
> Now a step by step work over, including HP mods for later units like > replacing the 74196’s in the synthesizer module with 74LS196. May have been > end of life of the 74196. With some slight change of the circuit, you should be able to replace the 74196 by an 74163 which is available as LVC and thus should be around for the next 10-20 years at least. > Now to the purpose of this post. The A9 module is after 88 a significant > change and Corby sees an improvement against his Maser. We are doing a board > and maybe some other will be interested. What does the A9 module do, for those of us who have not learned the inner workings of the 5065 by heart? "Integrator Assembly" doesn't say too much.... > Here are the issues > A is the LT1793 the best choice the time constant is 0.05 seconds with a > 10 K resistor and 5 uF Capacitor What are your constraints? For every single parameter, there is an opamp that beats the LT1793. Do you just want to replace the opamp on A9 or build a new A9 from scratch? If you can live with a power supply <12V, then I'd go for the LTC6240HV. > B should we add resistors and decoupling on the + - 15 volt op amp supplies Depends on the noise of the power supply. My experience is, that resistors in the power path causes more trouble than not having them. Though, I highly suspect those were mostly caused by improper design. If you have problem with noise on the power supply, I would rather suggest to use some low noise LDOs instead. The TPS7Axx family from TI has quite a few offerings of suitable LDOs. They are not on par with the LT3042, but they beat anything you will have in 5065. And they are easier to solder :-) > C Gold plating the edge connecter, does any one know a reasonable source, > or is doing it at home an option and if yes, how best way to do so. There are gold plating solutions available, if you want to do it at home. Though I would suggest to choose a PCB manufacturer that offers it. In europe, i'd recommend Eurocircuits, but i'm pretty sure you have a similarly cheap shop in the US. There are probably some shops in China that offer that as well. Mind you, gold plating will increase the PCB cost considerably, as it's a non-standard process. Not to mention that you need hard gold for connector contacts, which is different from the standard gold plating you will get as surface finish. Attila Kinali -- It is upon moral qualities that a society is ultimately founded. All the prosperity and technological sophistication in the world is of no use without that foundation. -- Miss Matheson, The Diamond Age, Neil Stephenson _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.