Repair of a Roland sampler circa 1987 - Page 1
Forum section: electronics / repair

author: OilsFan
author_rank: Regular Contributor
timestamp: November 21, 2014, 04:12:46 am
content: Hello, I made a video of a repair I did to an old Roland S-550 sampler. It was just a cracked solder joint but I did video the main board so it might be interesting to vintage electronics geeks.http://youtu.be/MXpvqFQ9KuQ

author: Yago
author_rank: Frequent Contributor
timestamp: November 21, 2014, 05:34:25 am
content: Was watching it and YT crapped out!Will try again later.

author: Yago
author_rank: Frequent Contributor
timestamp: November 22, 2014, 02:32:45 pm
content: Had a watch of the vid, and I have to be honest here, or GE et al ()will shout at me again!There is not really a repair vid in this, the fault was too simple and self explanatory.There were no explanations of the choice of tool, materials, or proceed to the rework part.On the teardown sections, I think it's great to see the likes of Dave and Mike at work, can almost hear the cogs turning and the database pages flipping in their heads.For us mere mortals, I think it would be acceptable to note and research the parts of interest before the vid, so you can include that info.On the good side, I like looking at the internals of oldish synths, mostly because like this Roland series I wanted one!Do you run that sampler on mono out only always?

author: OilsFan
author_rank: Regular Contributor
timestamp: November 23, 2014, 01:58:39 am
content: Quote from: Yago on November 22, 2014, 02:32:45 pmI hear you but in no way would I ever claim to be a Dave or Mike so you get what you get.Just posting for people who might have trouble with their units. That S-550 is new to me so I've only run it with mono out. I run my S-760's and MPC-2000 in stereo and my W-30 I use about 4 mono outs on it.

author: Yago
author_rank: Frequent Contributor
timestamp: November 23, 2014, 11:51:47 am
content: Yes, not meant as insulting, and the chaps here are often of that high level (not me, I am lurking in the shadows still!).Repaired a Kurtzweil of that generation once, lordy the pcb was knackered, traces leaping off the board like lemmings.In fact, that can be quite common, mainly in the interface boards and not the processor board.Processor boards, being at least double-sided, high-quality, the rest are normally single-sided cheapo boards.Might be some keyboard repairs headed my way soon, will post anything interesting.I won't be doing a video though, my humour is at best tolerated here (), and I have a face for radioThere's a few musicians and synth masters here, Lektoid springs to mind, have a search!

author: SeanB
author_rank: Super Contributor
timestamp: November 23, 2014, 12:05:55 pm
content: I learned a bit there, especially about those evil soldered in lookalike connectors, though those often can be told apart after close looking to see there is no polarising lug on the bottom, but some look almost identical to the plug apart ones till you see the small gap under it where the crimps are.I have seen some on printers that require you to almost disassemble the unit to get to the other end, you can see the design for assembly there, in that the board that fails most ( like the power supply) is put in the unit first, then it is built around it. You can see the board, undo the screws and such but to get it out you have to remove all the case, remove the main board and such to just undo the connectors to get enough slack to turn the board over to solder in new parts.

author: rsjsouza
author_rank: Super Contributor
timestamp: November 23, 2014, 01:08:06 pm
content: Wow, that was really nice to look inside the guts of a S-550. I can attest for the quality of the build and the components used. I still have my W-30 (bought new in 1991) and it works and sounds absolutely fine, with no flimsy connections nor blown caps!The eight track outputs were astonishing at the time, although I never used more than four in mine (when I recorded to my dad's Akai GX-270D-SS quadraphonic reel-to-reel)On the W-30, the SCSI-1 interface option was about $300 at that time, and an external 80MB SCSI hard drive was more than $1000. The W-30 alone was $2300, therefore it was something not for the faint of heart. I can find the SCSI-1 IC on eBay (not sure if they are fake or not), but a working SCSI-1 HD in good shape (and a reasonable price) is another story.A few remarks about the ICs you found.The custom Roland ICs are really a nightmare to find, and can only be replaced by scavenging other gear...At 14:23, these are standard EPROMs (16k x 8bit), and the SRM20256s are 32k x 8bit RAMs. I am not sure if the S-550 had internal wavetables in ROM, but surely the RAMs are the sample memory.At 14:46, it is interesting to see "S-50" on the custom IC, which is probably shared with its S-50 sampler brother.At 14:53, that is the Floppy disk controller from Western Digital.At 15:09, the NEC is probably a display controller of some sorts.At 15:36, among the sea of RAMs I was amazed to see aTMS3556from TI, a video processor for the external monitor connection.Overall, nice video!