On Wed, 15 Feb 2017 12:00:56 -0500, bitrex wrote:> On 02/15/2017 11:41 AM, Tim Wescott wrote: >> On Wed, 15 Feb 2017 08:35:44 -0500, bitrex wrote: >> >>> The Yamaha TX81Z, circa 1986: >>> >>> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg >>> >>> Big transformer, linear regulators, two-sided board, bunch of DIPs. >>> >>> Looks like the power switch is on the left at the back, and they've >>> routed some long piece of metal around the regulator heatsinks all the >>> way to the front panel. Anyone know why they'd do that? >>> >>> The ICs seem scattered all over with not a lot of rhyme or reason to >>> their positioning - make room for all the jumpers? >> >> One sided board. >> >> The long bar looks plastic. >> >> > Yep. As Spehro said, the routing does look like quite a PITA: > > http://imgur.com/a/wc1nC > > Wonder if they used some early "tool assist" to help with that, or if it > was all done by brain...You could make a two-layer board in your EDA tool, choose "vias" big enough to solder wires into, and then lay it out by hand with the understanding that you're really just putting in jumper wires. I've never done it, but it'd probably speed things up. This sort of product lets you flog the engineering because you'll make so damned many of them. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work -- see my website!
Old-timey design from not too long ago
Started by ●February 15, 2017
Reply by ●February 15, 20172017-02-15
Reply by ●February 15, 20172017-02-15
On Wednesday, 15 February 2017 17:01:03 UTC, bitrex wrote:> On 02/15/2017 11:41 AM, Tim Wescott wrote: > > On Wed, 15 Feb 2017 08:35:44 -0500, bitrex wrote:> >> The Yamaha TX81Z, circa 1986: > >> > >> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg > >> > >> Big transformer, linear regulators, two-sided board, bunch of DIPs. > >> > >> Looks like the power switch is on the left at the back, and they've > >> routed some long piece of metal around the regulator heatsinks all the > >> way to the front panel. Anyone know why they'd do that? > >> > >> The ICs seem scattered all over with not a lot of rhyme or reason to > >> their positioning - make room for all the jumpers? > > > > One sided board. > > > > The long bar looks plastic. > > > > Yep. As Spehro said, the routing does look like quite a PITA: > > http://imgur.com/a/wc1nC > > Wonder if they used some early "tool assist" to help with that, or if it > was all done by brain...Long bars screwed to large boards are for mechanical support. They can also serve as partial barriers or screens. Automated track placement would have been used in a large company in 86. It goes back longer than that. NT
Reply by ●February 15, 20172017-02-15
On Wed, 15 Feb 2017 14:36:44 -0800, tabbypurr wrote:> On Wednesday, 15 February 2017 17:01:03 UTC, bitrex wrote: >> On 02/15/2017 11:41 AM, Tim Wescott wrote: >> > On Wed, 15 Feb 2017 08:35:44 -0500, bitrex wrote: > >> >> The Yamaha TX81Z, circa 1986: >> >> >> >> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg >> >> >> >> Big transformer, linear regulators, two-sided board, bunch of DIPs. >> >> >> >> Looks like the power switch is on the left at the back, and they've >> >> routed some long piece of metal around the regulator heatsinks all >> >> the way to the front panel. Anyone know why they'd do that? >> >> >> >> The ICs seem scattered all over with not a lot of rhyme or reason to >> >> their positioning - make room for all the jumpers? >> > >> > One sided board. >> > >> > The long bar looks plastic. >> > >> > >> Yep. As Spehro said, the routing does look like quite a PITA: >> >> http://imgur.com/a/wc1nC >> >> Wonder if they used some early "tool assist" to help with that, or if >> it was all done by brain... > > Long bars screwed to large boards are for mechanical support. They can > also serve as partial barriers or screens. > > Automated track placement would have been used in a large company in 86. > It goes back longer than that.I think he's referring to the mechanical link from the button on the front panel to the switch behind the heat sink -- it's the sorta-silvery gray thing at the far left, kind of sneaking around the heat sink. But yes, the bar about 1/4 of the way to the right is a mechanical support. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work -- see my website!
Reply by ●February 15, 20172017-02-15
On Wed, 15 Feb 2017 09:44:41 -0500, the renowned bitrex <bitrex@de.lete.earthlink.net> wrote:>On 02/15/2017 09:42 AM, bitrex wrote: >> On 02/15/2017 08:53 AM, Spehro Pefhany wrote: >> >>> It's a single-sided paper-based phenolic board- and it looks like >>> they've laid out an 8-bit microprocessor (maybe a Z80 or 8051 >>> variant?) with external EPROM and RAM.. so yeah there are a lot of >>> interconnections in the digital part of the circuit and few components >>> to use as jumpers- looks like it was a massive PITA to lay out. >>> >>> --sp >>> >> >> The service manual shows it using the somewhat obscure (to me) "63803X" >> uP, plus an "XB 186002" 64kbit ROM chip, and a "TC5544PL" 8kbit RAM >> chip, to scan the front panel and MIDI and drive the 4 op FM chip (YM2414.) > >Oops, it's "63B03." I guess it's a 6809 variant. Hi tek!I think (from memory) it's the ROM-less version of the 6305, which was Hitachi's licensed (but vastly improved) CHMOS version of the Motorola 6805. --sp -- Best regards, Spehro Pefhany
Reply by ●February 16, 20172017-02-16
On Wednesday, 15 February 2017 23:35:14 UTC, Tim Wescott wrote:> On Wed, 15 Feb 2017 14:36:44 -0800, tabbypurr wrote: > > On Wednesday, 15 February 2017 17:01:03 UTC, bitrex wrote: > >> On 02/15/2017 11:41 AM, Tim Wescott wrote: > >> > On Wed, 15 Feb 2017 08:35:44 -0500, bitrex wrote: > > > >> >> The Yamaha TX81Z, circa 1986: > >> >> > >> >> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg > >> >> > >> >> Big transformer, linear regulators, two-sided board, bunch of DIPs. > >> >> > >> >> Looks like the power switch is on the left at the back, and they've > >> >> routed some long piece of metal around the regulator heatsinks all > >> >> the way to the front panel. Anyone know why they'd do that? > >> >> > >> >> The ICs seem scattered all over with not a lot of rhyme or reason to > >> >> their positioning - make room for all the jumpers? > >> > > >> > One sided board. > >> > > >> > The long bar looks plastic. > >> > > >> > > >> Yep. As Spehro said, the routing does look like quite a PITA: > >> > >> http://imgur.com/a/wc1nC > >> > >> Wonder if they used some early "tool assist" to help with that, or if > >> it was all done by brain... > > > > Long bars screwed to large boards are for mechanical support. They can > > also serve as partial barriers or screens. > > > > Automated track placement would have been used in a large company in 86. > > It goes back longer than that. > > I think he's referring to the mechanical link from the button on the > front panel to the switch behind the heat sink -- it's the sorta-silvery > gray thing at the far left, kind of sneaking around the heat sink. > > But yes, the bar about 1/4 of the way to the right is a mechanical > support.Ah, I didn't see that, page didn't render well. Extension bars on mains switches were common then. And LEDs. NT
Reply by ●February 16, 20172017-02-16
On Wed, 15 Feb 2017 23:49:57 -0800, tabbypurr wrote:> On Wednesday, 15 February 2017 23:35:14 UTC, Tim Wescott wrote: >> On Wed, 15 Feb 2017 14:36:44 -0800, tabbypurr wrote: >> > On Wednesday, 15 February 2017 17:01:03 UTC, bitrex wrote: >> >> On 02/15/2017 11:41 AM, Tim Wescott wrote: >> >> > On Wed, 15 Feb 2017 08:35:44 -0500, bitrex wrote: >> > >> >> >> The Yamaha TX81Z, circa 1986: >> >> >> >> >> >> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg >> >> >> >> >> >> Big transformer, linear regulators, two-sided board, bunch of >> >> >> DIPs. >> >> >> >> >> >> Looks like the power switch is on the left at the back, and >> >> >> they've routed some long piece of metal around the regulator >> >> >> heatsinks all the way to the front panel. Anyone know why they'd >> >> >> do that? >> >> >> >> >> >> The ICs seem scattered all over with not a lot of rhyme or reason >> >> >> to their positioning - make room for all the jumpers? >> >> > >> >> > One sided board. >> >> > >> >> > The long bar looks plastic. >> >> > >> >> > >> >> Yep. As Spehro said, the routing does look like quite a PITA: >> >> >> >> http://imgur.com/a/wc1nC >> >> >> >> Wonder if they used some early "tool assist" to help with that, or >> >> if it was all done by brain... >> > >> > Long bars screwed to large boards are for mechanical support. They >> > can also serve as partial barriers or screens. >> > >> > Automated track placement would have been used in a large company in >> > 86. >> > It goes back longer than that. >> >> I think he's referring to the mechanical link from the button on the >> front panel to the switch behind the heat sink -- it's the >> sorta-silvery gray thing at the far left, kind of sneaking around the >> heat sink. >> >> But yes, the bar about 1/4 of the way to the right is a mechanical >> support. > > Ah, I didn't see that, page didn't render well. Extension bars on mains > switches were common then. And LEDs.LEDs are common now, too, as long as they're blue. I was really hoping that the "stick a blue LED on it so it'll be MODERN!" thing would be a flash in the pan, but it's been a decade, and consumer devices with blue LEDs are still not seen as being charmingly dated. -- Tim Wescott Control systems, embedded software and circuit design I'm looking for work! See my website if you're interested http://www.wescottdesign.com
Reply by ●February 16, 20172017-02-16
bitrex <bitrex@de.lete.earthlink.net> wrote:> On 02/15/2017 10:23 AM, Don Kuenz wrote: >> Spehro Pefhany <speffSNIP@interlogdotyou.knowwhat> wrote: >>> On Wed, 15 Feb 2017 08:35:44 -0500, the renowned bitrex >>> <bitrex@de.lete.earthlink.net> wrote: >>> >>>> The Yamaha TX81Z, circa 1986: >>>> >>>> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg >>>> >>>> Big transformer, linear regulators, two-sided board, bunch of DIPs. >>>> >>>> Looks like the power switch is on the left at the back, and they've >>>> routed some long piece of metal around the regulator heatsinks all the >>>> way to the front panel. Anyone know why they'd do that? >>> >>> The power switch controls the mains directly- to run traces to the >>> front would require a lot of space on the board. Or they'd have to run >>> thick wires insulated to the satisfaction of every safety agency in >>> the world where they wanted to sell units. >>> >>> It's cheaper and better to put all the mains-connected stuff together, >>> near the power entry and operate the power switch with a button >>> extender. IIRC my old Tek scope has something similar. >>> >>>> The ICs seem scattered all over with not a lot of rhyme or reason to >>>> their positioning - make room for all the jumpers? >>> >>> It's a single-sided paper-based phenolic board- and it looks like >>> they've laid out an 8-bit microprocessor (maybe a Z80 or 8051 >>> variant?) with external EPROM and RAM.. so yeah there are a lot of >>> interconnections in the digital part of the circuit and few components >>> to use as jumpers- looks like it was a massive PITA to lay out. >> >> IIRC the innards my Yamaha pf-70 look about the same. Its microprocessor >> will be noted the next time it's opened. > > Historically Roland seemed to prefer Intel-derived processors in its > products (8051 etc.), Korg and Yamaha liked Motorola/Hitachi, while the > US manufacturers (E-mu, Oberheim) liked Zilog/MOSTek.My memory's wrong this time. The pf-70 uses a double sided FR4 PCB. All components are through hole. (It's several decades old.) It also uses an HD6303RP MPU. So the board that looked like the TX81Z was in my bone pile within the past year. It probably came out of a failed printer or scanner that was manufactured during the past ten years. Thank you, -- Don Kuenz KB7RPU
Reply by ●February 17, 20172017-02-17
On 02/16/2017 02:58 PM, Tim Wescott wrote:> On Wed, 15 Feb 2017 23:49:57 -0800, tabbypurr wrote: > >> On Wednesday, 15 February 2017 23:35:14 UTC, Tim Wescott wrote: >>> On Wed, 15 Feb 2017 14:36:44 -0800, tabbypurr wrote: >>>> On Wednesday, 15 February 2017 17:01:03 UTC, bitrex wrote: >>>>> On 02/15/2017 11:41 AM, Tim Wescott wrote: >>>>>> On Wed, 15 Feb 2017 08:35:44 -0500, bitrex wrote: >>>> >>>>>>> The Yamaha TX81Z, circa 1986: >>>>>>> >>>>>>> http://i254.photobucket.com/albums/hh102/gjm_photo/TX81Z1.jpg >>>>>>> >>>>>>> Big transformer, linear regulators, two-sided board, bunch of >>>>>>> DIPs. >>>>>>> >>>>>>> Looks like the power switch is on the left at the back, and >>>>>>> they've routed some long piece of metal around the regulator >>>>>>> heatsinks all the way to the front panel. Anyone know why they'd >>>>>>> do that? >>>>>>> >>>>>>> The ICs seem scattered all over with not a lot of rhyme or reason >>>>>>> to their positioning - make room for all the jumpers? >>>>>> >>>>>> One sided board. >>>>>> >>>>>> The long bar looks plastic. >>>>>> >>>>>> >>>>> Yep. As Spehro said, the routing does look like quite a PITA: >>>>> >>>>> http://imgur.com/a/wc1nC >>>>> >>>>> Wonder if they used some early "tool assist" to help with that, or >>>>> if it was all done by brain... >>>> >>>> Long bars screwed to large boards are for mechanical support. They >>>> can also serve as partial barriers or screens. >>>> >>>> Automated track placement would have been used in a large company in >>>> 86. >>>> It goes back longer than that. >>> >>> I think he's referring to the mechanical link from the button on the >>> front panel to the switch behind the heat sink -- it's the >>> sorta-silvery gray thing at the far left, kind of sneaking around the >>> heat sink. >>> >>> But yes, the bar about 1/4 of the way to the right is a mechanical >>> support. >> >> Ah, I didn't see that, page didn't render well. Extension bars on mains >> switches were common then. And LEDs. > > LEDs are common now, too, as long as they're blue. I was really hoping > that the "stick a blue LED on it so it'll be MODERN!" thing would be a > flash in the pan, but it's been a decade, and consumer devices with blue > LEDs are still not seen as being charmingly dated. >Red, yellow, and green remind people of traffic lights - and nobody likes traffic lights! I notice a lot of stuff uses off-white indicator lights now; I think we really want to go back to incandescent lamps.
