I did it that way for years, especially since that was the only way with tape, Mylar and Bishop Graphics stickies. My first Eagle board was done without a schematic in 1992, but it only had one 16 pin DIP chip and 4 transistors.
PCB work at Motorola was a different story. Only "properly trained professional PCB designers" could even open up a design that was intended for production. I was never one of those people. I built prototypes that were NEVER to be sold, so I did not have to play by all of the rules, but I did have to use the same design environment and workflow that the big boys used. That forced a schematic first design, but it also invoked a lot of rules checking that found problems early in a design. I also spent a good bit of of my 12 years of Mentor Graphics time learning how to cheat the system. It IS possible to do a layout in MG without ever making a schematic. It will be one giant ball of design errors, but with a bit of trickery one could generate Gerbers and send them to the in house PCB shop. This was best used for simple test boards without solder mask for things like a single transistor RF power amp where you are likely to tune the board with an xacto knife. .
Today I rarely try to cheat the system since the system has saved me several do-overs.
My DRC comes down to if I laid out the connections right. I've made most recently, a mistake where I swapped pin 7 and 8 of a tube on a 6E2 level board. Thankfully, it's easy enough to swap the resistor leads. If I had built it completely in EasyEDA, it would have caught that.
If there are glaring errors, I have found JLCPCB will spot them for me and halt production. If I spot them within a few minute, I can ask them to halt production and replace the Gerber. It's happened a few times.
My most complex board is only 100mm2 though and all through hole - hard to mess that up compared with what George worked on at Mot.
My most recent do-overs were the wrong pin angle for 6E2, and the 7 and 8 pin swapped on the 12AU7 part of the board that drives it. Oops. Better than the first run of board that were 180° out LOL A 6E2 is useless if it faces away from you, right?
If there are glaring errors, I have found JLCPCB will spot them for me and halt production. If I spot them within a few minute, I can ask them to halt production and replace the Gerber. It's happened a few times.
My most complex board is only 100mm2 though and all through hole - hard to mess that up compared with what George worked on at Mot.
My most recent do-overs were the wrong pin angle for 6E2, and the 7 and 8 pin swapped on the 12AU7 part of the board that drives it. Oops. Better than the first run of board that were 180° out LOL A 6E2 is useless if it faces away from you, right?
Back before PCB CAD was invented and for a long time after, electronic design and PCB layout were done by separate people. As an electronic design engineer I would pass both a schematic (usually hand drawn) and a major component placement to the PCB designer which would include details of mechanical fixings and positions of key conponenets. I would also provide details of special tracking requirements for power/ground, clock signals, position of decoupling and so on.
Cheers
Ian
Cheers
Ian
Up until I left Motorola in 2014 That was still the case. The cell phone and two way radio divisions each had at least 5 major design teams. The industrial design team dreamed up the concept of what a new product should look like, its feature set, user interface, size, weight, cost, etc. Many times, the stuff they asked for could not be built because the tech needed did not exist. Most of the time, we told them where to stick it, but sometimes we went off and invented the necessary tech. The mechanical design team figured out how to make the housing, chassis and all other physical parts needed for a product. They provided the board outline and height restrictions for each PCB used in the device and the X,Y,Z map that Mentor Graphics used for rules checking. The PC board design group laid out the boards. The software design team wrote the code for all of it. There were from one to three or four electrical design teams on a produce depending on the complexity. RF design, Digital design, power supplies and audio design, and an overall system architect. I was the RF design engineer on the most complex phone made at the time. There were 60+ engineers from all of these groups. Guess what happens when you put 60 engineers in one room and ask them to design a phone? Well, it took two years to get the i2000, and that's why I left the phone group back in 2000, and partly why Motorola, who INVENTED the cell phone in no longer in that business.
snip
Somewhat OT, back in the late 80s I worked at The Technology Partnership (TTP) in Melbourn, Cambridgeshire. Our TTPCom division developed its own GSM chip set and licensed it to the likes of Sony and Samsung because in those days the only people making GSM chip sets were Motorola and Nokia. In 1999, TTPCom was purchased by Motorola for a sizeable chunk of money and it was because of this that in 2000 I was able to retire at the age of 50.
Cheers
Ian