VOGONS


First post, by RetroNoob

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How easy is it to flash my own Roland SC-55 v1.21 rom?

I have a SC-55 with a v1.20, and I'd like to flash a v1.21. Understand that a new chip needs to be put in, but I can't find the process to do so.

Reply 1 of 12, by keropi

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You burn a 27C020 or similar eprom with the new 1.21 data, open the unit - remove old rom - insert new one - close the unit.
It is more complicated if your original 1.10 rom is soldered directly to the pcb.

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Reply 2 of 12, by RetroNoob

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Can you expend a bit more on the process? It's the flashing of the eprom with which file(s) I need a bit more help with. I have files saying, ic23, ic26, ic27 and ic28.

I've bought the kit to flash a rom, and have the correct eprom.

Reply 3 of 12, by keropi

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IC23 is the rom , it's size is 256kbytes - same as what the 27C20 eproms can hold 😀

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Reply 4 of 12, by RetroNoob

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After reading some other posts - it seems "Stefan_L 1.21 rom dump" is the thing to have? Sadly he doesn't seem to be around any more, and I can't find links. From having the ic23, etc - does that mean I have the correct file? Going by the file name has it as a description as being sc-55 v1.21?

Reply 5 of 12, by keropi

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search inside your file, if you find this string: Ver1.21 121120118 '91/08 10 14:37 , then you are good to go.

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Reply 10 of 12, by Cloudschatze

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GTPZ71 wrote:

Is it possible to upgrade from version 1.0 to 1.21? If so, is it basically the same process as upgrading from rev 1.10?

Not without replacing the CPU from a donor 1.2x unit. The same requirement exists for a 1.10 to 1.21 upgrade.

zarkon wrote:

I'm curious, what actually changed from v1.20 to v1.21? I've never seen any info on that.

While anecdotal, I suspect the RPN bugfixes included in version 2.00 were included in 1.21. In addition, I've discovered potentially-related (and similarly resolved) issues with the bulk reception of NRPN data. The attached MIDI file exposes this NRPN misbehavior in < 1.21 units, as pertains to drum pitch modification.

These differences are completely irrelevant to known gaming usage however, to the extent that I have yet to upgrade the 1.20 unit in my split-channel SC-55 pairing to match its 1.21 counterpart.

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Reply 12 of 12, by zarkon

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Cloudschatze wrote:

While anecdotal, I suspect the RPN bugfixes included in version 2.00 were included in 1.21. In addition, I've discovered potentially-related (and similarly resolved) issues with the bulk reception of NRPN data. The attached MIDI file exposes this NRPN misbehavior in < 1.21 units, as pertains to drum pitch modification.

These differences are completely irrelevant to known gaming usage however, to the extent that I have yet to upgrade the 1.20 unit in my split-channel SC-55 pairing to match its 1.21 counterpart.

I see, cheers.