MKS-70 VFD to LCD conversion proof of concept

First attempt to use an LCD in place of the stock VFD.

The VFD on the Super JX is a well-known weak spot. Several people (including myself when mine failed) have wondered about the feasibility of putting a surrogate display in, but there are several mechanical and electrical problems, and I chose to just repair my VFD.

The topic came up again recently on the Roland JX list, about using an LCD, and since I've been "in the zone" lately, I figured I'd give it a go. Not a bad start.

The VFD is connected to the motherboard with a clock + serial data link. The protocol is kinda wacky, but not intractable. As I mention in the video, I have not yet solved the decimal/flashing issue yet. But I figured this was enough progress to put it up.

Hope you enjoy it!

Category:

Science & Technology

Tags:

• roland
• mks-70
• display
• vfd
• lcd

[randomvariate]

Top work. Nay, impressive. Where are you at with this at present?

[TheMindOfPat]

@randomvariate Augh... sorry, I changed email accounts and now I have like 5 months of backlogged comments :) Anyway, I got pulled away on a couple other projects so it's been left pretty much alone, but I should probably come back to it some day. The reception was sort of "it's an interesting novelty, but so what." Of course, that never stopped me before. ;)

[eminentband]

Wow, how did you do it?

[TheMindOfPat]

@eminentband Reading the bytes is the first challenge. Then it's "just" a matter of decoding them -- as you can see I still have a ways to go. It's a pattern of control and ASCII-type bytes. My guess is flashing and dots are flags in there but I haven't verified. Haven't had time to check Colin Fraser's disassembly but that might help. If you find out more let me know. :) Also my LCD is too slow to drive directly from the data, I needed to buffer it. Let me know how you're coming!

[timailsa36]

Good work fela. Would like to convert my MKS-70 if poss - where would I start?