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Any MX-80 users here?

PostPosted: Sat Apr 16, 2016 11:01 am
by Joetheman

I just became a member here... And I'm interested to see if there are any MX-80 users here.
I picked one up about a year ago and haven't done any session work with it, as it sits in my living room.
But as I'm going through it, everything appears to work correctly, other than the ERROR-90 that periodically show's up on the remote!
I have a very technical and musical background, so this machine is a nice toy to play with.
So, chime in here, I'd like know if there is some life here for the MX-80!!!

J. H.

Re: Any MX-80 users here?

PostPosted: Sat Apr 16, 2016 10:31 pm
by Trakworx Mastering
Welcome to the forum!

I use one. 2" 24 track. It's been very reliable and sweet sounding for a couple of decades here. Great machine.

Re: Any MX-80 users here?

PostPosted: Tue Apr 19, 2016 8:56 pm
by Joetheman
Hi Trakworx Mastering and thanks for the welcome to the forum!

I'm glad to see there is some life here!

I've hacking through the machine... In particular the remote interface card in the machine.
What I'm interesting in is locating a copy of the communications protocol between the comm
card and the remote. Over the past few months I've been trying to reverse engineer the EPRROM
contents from the remote interface card with the intent to understand that comm protocol.
I've hacked a lot of code in my lifetime, but this 8085 assembly code in this prom is UGLY!
In the 8 bit world my favorite CPU's have been the Z80 and especially the 68HC11 family that I
still work with in my present work environment! But that is another story all together!
As I look at this 8085 code, it reminds some of these old CPU's are really primitive. At least it's not
a 8008 or even 4004 CPU.

However, I do like the machine in general sense... It does appear to be a machine that will keep working
for years to come. And I like that!

So, keep in touch here! I would be happy to hear of you experiences with the machine! And BTW, are there any
technical things in the MX80 that bug you. Generally, I'm a hardware design engineer during the day so a machine
like this therapy when I'm away from work, as I push a lot of a paper at times... and manage projects.


Joe H.

Re: Any MX-80 users here?

PostPosted: Wed Apr 20, 2016 10:23 am
by Trakworx Mastering
I have no idea about the code stuff. Not my purview.

The only technical thing that bothers me is the way the calibration pots are mounted on the cards. It's too easy to bend them back and then they can break due to metal fatigue. Be gentle with them.

Other than that, whenever it has acted up (very very rarely) I have solved it by simply re-seating the control cards and cleaning the contacts.

The toggle switches on my remote are starting to wear out - they get stuck and after I work them free they end up very loose, but they still work. Please let me know if you find a source for replacement switches.

You may find something useful here: ... ight=mx+80



Re: Any MX-80 users here?

PostPosted: Fri Apr 29, 2016 9:05 pm
by Joetheman

I did a search for "switch japanese manufacturer" and identified several switch manufacturers.

Check out digikey: ... ND/1056855

OR, ... tches.html

We may not be able to find the identical Otari switches, but a divide and conquer approach
is sometime the only way to go... The NKK switch at digikey appears to have the basic mechanicals
to fit into the pcb. Looking at the bottom of the pcb and comparing the electrical and mechanical
interfaces, its a start! Download NKK's catalog, its for their M2 rocker switches. I haven't
removed the switch pcb or have my measurement tools at home to get a better idea of the dimensions.

But this is a start!

Re: Any MX-80 users here?

PostPosted: Sat Apr 30, 2016 5:32 pm
by Joetheman

Here is my investigation to locate a replacement switch for the remote.

1. Per the schematic, DWG No. 3-12620, Name: Dispaly PCA, Part No PB7JA0A, applied PB-7JAA
SW1-64 and 67 are Otari part number, WH42057, Description LB(C)-22M-095.

2. Per Section 8 of the Otari manual, [9] PB-7JAB Display PCB Assembly,
Ref Number SW3-10 Desc: Switch, Part Number WH42057. With corresponding Ref Number SW3-10
Desc: Lever, Switch. Part Number KN3002, Notes Vermilion.

From the above part number WH42057 and description LB(C)-22M-095, I get the impression that the
switch is a two piece assembly. One is the switch and the other is the lever (handle). I may be wrong,
as I haven't disassembled my remote to find out!! But I may be right... Please, someone chime in
and correct me if I'm wrong!

Anyway, a search of the description, LB(C)-22M-095 was not successful. Even using a fraction of
the description and searching several of the parts finders was unsuccessful!

Anyway, some wild searching on the net and pictures lead me to some surplus switches which
appear to have very similar looking mounting and lead placements when compared to the
PCB board layout in the manual and the actual solder side of my remote pcb assembly.

So, that lead me to the Tyco Electronics CST Series, Baton Toggle, Multiple Pole switch.
I don't have my micrometer to measure the actual dimensions on the pcb assembly, but they
appear to be worth a much closer look for proper mounting into the pcb assembly.

Anyway, the part number is CST022NK and manufactured by TE Connectivity Alcoswitch.
Digikey has none in stock, but it has an alternate part number, 1437576-2 which is
a TE internal part number.

This is a direct link to TE Connectivity's page:

Searching for a quantity of either part number CST022NK or 1437576-2 was unsuccessful ... OUCH!!!

However, 4 star electronics an obsolete electronics components distributor ... 22&x=0&y=0

shows some inventory, as follows:

CST022 Quantity of 34
CST022K Quantity of 9
CST022N Quantity of 65

Another parts house, Harry Krantz ... art=cst022

Shows 3000 pcs are available of CST022NK


Shows 26053 pcs of CST022 are available!

From experience, I know 4 star is without question and is a very reliable source.
I don't know about the other two however.

So, perhaps we stand a chance of keeping those remotes alive!!!


Joe Hammer

Re: Any MX-80 users here?

PostPosted: Mon May 02, 2016 11:12 am
by Trakworx Mastering
Wow, thanks Joe, for such a thorough research job! That will be a big help when I tackle the remote switches :)