Roland I believe has the highest number of products to be covered here. And a very diverse array of them. The SH-1000 was their first synth product. Kakehashi started Ace Electronics in the mid 50's and did some attempts at a theramin and other products including a Hawaiian guitar amplifier in the late 50's and organs in the early 60's. Roland was conceived in 1972. The Sound on Sound part 1 article gives a good detail of the early history and products of Roland to 1978. Sound on Sound part 2 conintues to 1985. Here is a pdf which gives the Corporate History from Roland's own site with other current product links etc.
From a technical standpoint, the company has used fairly high reliability parts it seems over the years. Many of their oldest units are still working according to postings I see. I would say there might be slightly higher rates of problems than Yamaha gear of the 80's and perhaps visa versa for the 70's. But Roland has handled their service issues well and they stock parts for much longer than Yamaha (which is 5 years)! It's always a pleasure doing business with them in my experience.
While the company doesn't really stand out in terms of pioneering accomplishments like Hammond, Moog, ARP, Sequential or Yamaha, they do stand out in making very musically useful instruments that have a good track record and LOTS of them! Always striving to improve interface and sound quality on previously existing ideas.
Many of the actual sounds used in Roland gear from 1984 with the JUNO-106 to the XP's, JP8000/8080, V-drums etc. were done by Eric Persin of Spectrasonics
Here is a page with Roland Custom IC's Info. and factory patches and other info.
Here is an article comparing the rare BA662 vca chip with more common BA6110 at Subatomicglue.com or see pinout comparison below.
Roland serial numbers until 1989 use a month code from the first two digits which is shown in this month table
SH-1000 SH-2000 SH-3(A) RS-101/202 SH-5 SH-1 SH-2 SH-7 JP-4 Pro Mars VP-330 RS-09 Saturn09 SH-09 JP-8 Juno-6 Juno-60 SH-101 JP-6 JX-3P / MKS-30 MKS-80 Juno-106 MKS-10 MKS-7 JX-8P JX-10 / MKS-70 Alpha Juno1 / Juno2 / MKS-50 MKS-20 S-Series D-50 / D-550 D-10 / D-110 D-20 U-20 / U-220 D-70 JD-800 / JD-990 JV-90/JV-80/JV-50/JV-35 XP-50/JV-1080 XP-60 / XP-80 JV-2080 JV-1010 Fantom
General parts note. 1) A few units use the VCF/VCA module 80017A which are failure prone. This has been discovered to be due to crystals growing and shorting things out in the potting. Immersing modules in acetone and melting away the potting material seems to clear the issue up. I've seen leg come off from mishandling during removal. But that's not the issue that usually takes them out I guess. 2) The BA662 is completely unavailable generally but BA6110 may be substituted I'm told using this pinout:
* BA6110 to BA662 pin conversion
Pin 1 = Pin 3
Pin 2 = Pin 2
Pin 3 = Pin 4
Pin 4 = Pin 1
Pin 5 = Pin 5
Pin 6 = Pin 6
Pin 7 = Pin 7
Pin 8 = Pin 8
Pin 9 = Pin 9
Roland SH 1000 SH 2000 SH 3 SH 3A SH3 SH-3 SH5 SH1 SH2 SH7 JP4 Jupiter-4 Compuphonic Promars Pro-Mars Compuphonic RS09 VP330 Saturn-09 SH09 JP8 Jupiter-8 Jupiter8 Juno6 Juno60 SH101 JP6 Jupiter-6 Jupiter6 JX3P MKS30 MKS80 Juno106 MKS10 MKS7 JX8P JX10 Super JX MKS70 Super JX module Alpha Juno-1 Alpha Juno-2 MKS50 MKS20 S50 S550 D10 D110 D20 U20 U220 D70 JD800 JD990 Super JD JV1080 Super JV XP50 XP60 XP80 JV2080 JV1010