Ask HN: Help me restore the LCD displays on classic samplers so I can use them

I did a backlight replacement on a S3000XL, a LCD replacement on S900, and found a cheap ($25?) LCD replacement for ASQ10 (same as MPC60/MPC3000).

Jazzcat + Ebay sell expensive replacements, but they are actually just cheap LCD displays with the driver circuit bypassed (since the MPC/sampler has a discreet IC) and an epoxy blob to prevent copycat work.

I need to dig up the wiring diagram, but the gist was from an EEVBlog forum post and only took an evening to reverse engineer.

This looks like the post I referenced -- https://www.eevblog.com/forum/beginners/modifying-a-240x64-l...

Thank you kindly.

I could only find a service manual for the MPC3000 (on archive.org), but the schematic in that one shows the LCD is controlled by an LC7981 display controller.

This interfaces with the CPU's bus and produces very low-level clock & data signals to the LCD panel (CL1/CL2/FLM/MB/D1) - basically a stream of pixels along with synchronization pulses.

Nowadays most "graphic LCD" modules will incorporate a similar chip on-board, so that they can present a simple 8-bit parallel interface.

Capturing + translating the signal would be tricky - it's not _terribly_ fast (240x64x60Hz) but there's no flow-control or error-correction, basically low-resolution video capture

AKAI S2000 S3000XL S3200XL EB16 IB-208P SERVICE MANUAL: https://elektrotanya.com/akai_s2000_s3000xl_s3200xl_eb16_ib-...

According to photos on the web, the display module has 3x LC7940 and 1x LC7942 on the backside.

ok thank you for the breakdown

I hate to suggest that "it's not worth it" but that is often the case. I think it's fun to try and do, and it's taught me a lot. But if the goal is to make music, then it's maybe not the strongest strategy.

Yes, they were professional equipment. Yes some have unique workflows or analog stages that make them interesting.

That said, having fixed a lot of audio equipment in my life, there are a lot of off-the shelf parts for things and a lot of close equivalents.

For instance, the display in the Roland XP10 keyboard uses a pretty standard, segmented LCD controller. All I had to do was figure out how to connect the ribbon cable to some specific pins on the controller, set a color (because the controller I added was now backlit, which is an upgrade).

And then you discover that the plastic on the keys has some deformation over the course of 40 years, so everything is sticky and you need to get a dremal and rework every key.

In any case, I found that with these kinds of long term projects, your are often better off "going back to school":

get an arduino and a couple of different controllers that seem similar to the one in the devices you're interested in,

build some displays that are similar in topology to those displays

find the schematics for devices-of-interest

build some similar displays until you understand how the displays are working in those devices.

After you've done a little work like that, you can start to look at schematics and datasheets and figure out what kinds of parts that you're needing to implement the display.

IME, that's a couple of hours a week for a couple of months, but after that you're in a place where you can do what you'd like as far as avoiding $250 drop-in replacements.

Unfortunately, with your s3000, it may be the case that there is a different issue- the memory is non-functional (about 20 years ago, I had an s2000 go wonky cause the diodes in the cheap simm I put in it blew up).

Anyhow, if you're a software guy, then you know how to learn stuff- you're gonna have to give yourself a little hardware school before you can do what you'd like to do.

I found it fun, but in retrospect my time would have maybe been better spent making music or making money so I could afford time to make music.

As someone who lusted after music hardware my entire youth (and has a broken Roland XP80 and Akai S01 and hundreds of useless floppies and a working DX7 and TX81z sitting behind me) I have to agree. Especially for hardware that is 100% in the digital domain or where you will be doing a ton of manual manipulation, just use a laptop.

Get a copy of RX950 (https://www.inphonik.com/products/rx950-classic-ad-da-conver...) and Decimort 2 (https://d16.pl/decimort2) or whatever the newest equivalent is to fill you Akai sampler sound needs. If you really want to twist knobs, I have a Novation 49SLMkIII (https://us.novationmusic.com/sl) with 8 encoders mapped to all kinds of things in my default Ableton template. It's so friggen amazing (parts of the living in the future are really cool). I only wish there was a place for music collaboration in this future reality (and not just 'I can't be bothered to read the manual/learn music technique be my interactive manual' or horrible toxic negativity (looking at you KVR and GS)).

Edit: I prefer other filters than rx950 that have more flexibility only recommending it if you need a specific Akai replacement. BTW it's sometimes the included freebie at PluginBoutique. Jason Herd uses it to good use in this walkthrough https://faderpro.com/programs/making-minimal-tech-garage.

What you're paying for is the engineering effort that figured out how to put a more modern display in an old device. It's not an exact replacement. They tell you that. They even sell a new bezel to adapt this display to the old sampler. It's expensive because the market for this is tiny.

You can duplicate that effort. You can buy one, figure out what display they are using, and order more. You can order the bezel and duplicate it on a laser cutter. Is it worth it?

In my experience this sort of thing is definitely worth it due to the knowledge and insights you will gain. However, monetarily, expect to spend 2-3x the cost of the commercial offering (you will go through at least 2 and likely 4 or more revisions and components will cost more in low quantities).

Looking at a photo of the screen[1], it is a simple LCD dot matrix. I also read elsewhere that the problem is that the backlight tends to fade. So it seems like you have many options:

* Find an equivalent LCD matrix. This is probably not that hard. This display seems like a generic part and LCD matrix displays haven't changed much over time.

* Fix the backlight. That would mean taking the display apart and probably resoldering some LEDs, assuming that it's the LEDs and not, say, a capacitor that is causing the brightness to diminish.

Going beyond these options, you'd be getting into decoding the commands to the LCD driver chip and displaying those somehow, which will be custom hardware development.

[1] https://www.asari.jp/diary/archives/007355.html

Depends greatly on your level of experience with electronics repair.

In rough order of difficulty/complexity:

Simply remove the module, wipe down the connections with alcohol, reassemble. If there's a 'zebra strip', gently peel it off, clean both ends, reassemble. If you see improvement, repeat with care until all segments are alive again.

Replace the backlight. Depends on the exact module, but sometimes they're just simple LEDs that can be replaced.

Ensure the polarizing filters still work. You'll need to research LCD polarizing, it's more complicated than I care to explain in a HN comment. They can degrade and sometimes need replacing.

Beyond this, you're looking at an electrical fault or the display is just dead. You'd have to start probing the display driver to examine the signals. A good starting place is to replace all the electrolytic capacitors.

Barring that, you likely have a bad display module. Sometimes you can test them by connecting some pins to ground and just touching other pins with your finger. The static electricity in your body can be enough to flip segments on

I don't know how to specifically do what you want with certainty, but years ago I've managed to fix the unreadable LCD on my Roland MC-505 by baking it's board in the oven at low temp for a period of time. Look it up, it's a thing apparently. I was sceptical but it worked perfectly.

I heard from some people that this works because the solder gets bad over time potentially losing contact somewhere. Melting and resolidifying it resolves that issue.

Then I heard from somewhere else that it's actually not true. There's a very common (most common?) type of capacitor that very slowly loses capacitance over time. But heating it up and cooling it down resets it so it's like new.

Either way, I really wonder how much e-waste out there is just due to old solder/capacitors that could have been easily repaired.

> Either way, I really wonder how much e-waste out there is just due to old solder/capacitors that could have been easily repaired.

Actually, both are true!

The solder stuff ("Soldergate") was around the time when the EU RoHS directive came into force - around the late '00s IIRC. The most affected product was everything with a NVIDIA GPU [1] (including Apple, who then cut all ties with NVIDIA as a result), but AMD (or rather, back then ATI) was also hit as they manufactured the Xbox 360 GPU with its RRoD ("red ring of death") issue [2]. In all cases, the issue at the core was an untested combination of no-lead solder elements that didn't handle frequent high-amplitude heat/cool cycles all too well, and a common fix was indeed to bake the PCBs in an oven to achieve all solder balls getting equally hot, basically low-temperature DIY annealing.

The capacitor issue cropped up around the same time - an engineer had stolen the electrolyte formulation from his prior employer, mis-copied it and eventually through his new team defecting (and stealing the broken formulation...) it spread around the industry [3]. All electrolytic caps age (particularly if used at the upper end of their rated temperature scale!), but the ones made with the broken formulation age muuuuuuch faster. Note that there is no fix for a dried-out elcap, the only fix is replacing it and in the case of an exploded one, cleaning the entire board of spilled electrolyte.

The problem is in both cases, these issues are hard to troubleshoot without expert knowledge and tools, in-place measurement can be very tricky (say because a capacitor is in parallel with an IC or resistor), and even if you have both the knowledge and the tools, it can be a wild wild goose chase to repair a broken Thing as for 99.99999% of equipment (outside of cameras and some phone models where for whatever reason everyone and their dog leaks component-level repair guides?!) you will not find information regarding component values, small SMD parts have no distinguishable parts marking at all any more, and manufacturers keep adjusting PCBs between revisions (to keep up with compliance requirements, fixing hardware errata or just because a part becomes unavailable) without that being apparent to the customers.

We desperately need laws specifying that all PCB design files have to be submitted to the government and that they be released to the general public after the manufacturer ceases support.

[1] https://www.overclock.net/threads/inq-nvidia-gpu-defects-exp...

[2] https://de.ifixit.com/Device/Xbox_360

[3] https://en.wikipedia.org/wiki/Capacitor_plague

We desperately need laws specifying that all PCB design files have to be submitted to the government and that they be released to the general public after the manufacturer ceases support.

Aaaaand that's my daily reminder to read to the end of a given post before reaching for the vote buttons.

I'm happy to discuss my opinion especially after describing my reasoning, you just went for some completely unnecessary snark.

To extend on my reasoning: it seems like the camera and phone industry is still perfectly thriving despite very precise diagrams right down to circuit designs and component specifications being accessible via nothing more than a Google search for "sony <model> service manual level 3". There is a healthy ecosystem of devices and manufacturers on one side, and officially licensed as well as unlicensed repair shops on the other side, and there are many resellers for original spare parts as well that allow both larger operators and adventurous tinkerers to repair their devices on their own if they want.

Unfortunately, this cannot be said about a lot of other electronics branches where a lot of Things eventually become dead paper weights due to DRM, bespoke critical parts failing without spare part supply chains and/or information how things should work (say, test point voltages, signal patterns, ramp-up periods) or simply because the manufacturer vanishes off the face of the earth, forcing owners of such devices (assuming they still work after the manufacturer ceased paying server bills) to decide between doing what is right and discarding of stuff that poses a threat to other netizens or to keep their stuff running and have it hacked sooner than later.

Since the market has clearly failed to provide products that are built to last, the e-waste amount is clearly unsustainable and the electronics markets of Shenzhen with the wizards there being able to do virtually everything one desires cannot be replicated elsewhere, I propose strict governmental regulation.

It's worth noting that the screens are terrible, so the upgrade is well worth it.. but I get that it's a lot of money.

Check eBay - I got mine for much cheaper than MPC Stuff from a UK seller

This Reddit thread suggests that the backlight may be the problem, not the LCD display itself: https://www.reddit.com/r/akaiMPC/comments/15zdlac/need_sugge...

Can you tell if the pixels are correct and there’s just no light? If so, the LED backlight replacements mentioned would be the answer.

I also stumbled upon cases in which the backlight was the issue but OP wrote that "the screen while illuminated is entirely blank".

Ah, thank you, I had totally misread that as not illuminated and black. More caffeine required.

illuminated and backlit are two different things, there's a matter of polarization

I got a replacement for an Akai S1100 for $90 but that might have been cheaper than 3000

There’s videos on YouTube with guides on using old iPhone screens to illuminate the old screens.

I don't have specific advice to give you. But a few of the videos on the Posy YouTube channel are highly relevant. He has fixed some vintage HiFi gear displays. Not in depth technical in the videos but maybe he has a community or something? EEVBlog forum would have knowledgeable people too.

On this vintage of equipment it’s almost always the backlight. See if you can see a faint image if you use a very bright light on it. If you can, you can probably replace the cfl tube with a led strip.

Also these displays are still available, but usually come with driver ic’s blobbed on. You can probably just bypass the blob or even mount the lcd module on the old board. (They usually just are mechanically attached ). Buy a couple of cheap character displays of the same size to practice tearing them apart. You should be able to find them around 5 dollars for the 2 line displays.

Buy one of the replacement displays. Figure out what off the shelf part they used and buy some of them from AliExpress. They are using an off the shelf part and marking it up based on their technical knowledge and selling into a market segment with less technical knowledge.

Give yourself time to learn electronics and how to repair instruments. Maybe it will be your new hobby and you will buy an oscilloscope. Maybe it won't. Good luck.

^ This

As noted, the expensive MPC60/3k replacements are just generic T6963C / RA6963 displays with the circuit bypassed (since sampler has the LC7981) and the correct pitch ribbon cable soldered.

Yep, $25-30 240x64 RA6963 T6963 like https://www.buydisplay.com/graphic-lcd-240x64-module-display... plus removing the controller and SRAM

Exactly -- for the ASQ10 in my eBay history, it was https://www.ebay.com/itm/203144466152

Honestly, I'd probably just pay the premium and buy a kit if I did it today.

I did this during COVID lockdown when my hobby/project time was valued differently.

A lot of times the solder joints have aged and broken in electronics of that age. Are you competent with a soldering iron? You might have a simple reflow job.

If you want to convert the display, a Raspbeery Pi SBC is most likely absolute overkill. A microcontroller will do for sure and will be a fraction of the cost.

As I understand it, you just want to be able to control the device. Maybe keep the display as is, intercept the signals and forward them (wirelessly) to an external device for display?

>Intercept the signals and forward them (wirelessly) to an external device for display?

You are correct. Though I am fine with it being wired. The Pi is good since I already own it. Heck, I can use a laptop for it, since I have a couple.

Actually that would be cool since if somehow I could wire it up then I already have a big screen to render things on ,.

That would mean I needed a way to get the cable / signals to the PC. Sine I have an old laptop I might get to run Linux it would have serial and parallel ports if that would make it easier,.

Or some gizmo that takes the wires from the Akai sampler and makes USB

I mean, for one-off projects the RPi is plenty cheap. You’ve gotta have some scale for the cost difference to compensate for the convenience of working with a broad-based platform.

Especially if it’s like a RPi 2040

That‘s a microcontroller, like I suggested.

There are hundreds of standards for the pinout, then there are dozens of standards for the bus, then there are hundreds of standards for the display commands.

There are OLED displays available that have been adapted for a bunch of classic sampler/synths from that era to replace LCDs/VFDs.

Could you cheat and get a software patcher for the synths? I’ve done this in the past for an old Ob1 with similar screen issues

I have tried to find something and I havent found what I wanted. I should be able to hook a drive into the SCSI port and exchange samples but I do want to be able to use the native features, so I was hoping for a virtua control panel (mirror of what the screen should show)

This is hackerish but I think there are fairly specific forums for this kind of thing with experts and all the parts you need.

Try Gearspace.

these samplers used to cost $3000-5000

if you are concerned about $200 for a replacement kit you should probably sell them to someone else

They absolutely do not cost that much. These are rackmount and cost between $200-400 depending.

I disagree with the way he made his point, but the facts look right. The S300XL apparently retailed for £1799.[1] that would have been ~$2800 USD at the time, or north of $5k in today’s dollars.

1: https://web.archive.org/web/20150406014725/http://www.soundo...

Yeah but you can pick one up for a fraction of that these days - here's one for €350[0] and given the typical difference between Europe and the US for used gear, you could probably pick one up for under $300 in the US.

[0] https://reverb.com/item/74573558-akai-s3000-xl

They are cheap to find -- on Yahoo Auctions Japan I got an s3000xl for ~$80 since the 8-out works in the MPC2k/xl and go for as much as ~$400 alone.

But that doesn't mean anything about the cost to repair, upgrade, or in the case of LCD replacement, modernize. The memory, flash, effects, and expansion cards are highly sought after, and you're competing with bigger budget established producers.

I don't understand your point, to be honest.

My point was that it reasonable to be reluctant to spend $200 to $250 to replace a small component of a device that is only worth $300.

This was in response to someone who claimed the OP should just sell it if he didn't want to spend $200 to fix it - because it originally cost $3000-$5000.

Agreed -- the price contrast between the unit itself and the component replacements and upgrades is a turn-off, however going into a ~30 year vintage pro audio sampler thinking it will have a low cost of ownership or repair feels unfair.

Yes, the base unit themselves might be cheap. But once you're looking at enthusiast-produced LCD replacements or optionally-purchased-in-the-90s expansion cards, having sticker shock is expected.

LCD parts are cheap if you want to put the domain engineering work and solve engineering challenges yourself. They are expensive if you're one-stop buying a targeted kit and just trying to max out your upgrades.

An HN poster might be willing to put in significantly more time head-desking and soldering to save $200. A producer buying a vintage Akai is not necessarily looking for an EE project.

To that producer, the functionally upgraded unit is "worth" a lot more than $300 since they're selling the products of it.

https://www.ebay.com/itm/255438098835 this one is $160 roughly.. and it's worth it if you really like the sound and want to partially modernize. I got my S3000XL for $200, got the screen for another $160, DIMMs to max memory was only $20. The Zulu SCSI was $80.. So yeah, I did put a bunch into it but all that's worth it to me.

I agree that using original MSRP is absurd though. The S3000XL is a later model from them and can be found for cheap all over the place - they made a bunch of them.

S1100 series are sought after but those are usually close to $1k in excellent condition, and getting maxed out memory could cost $3-400.

S950 sell for over $1k usually as well.

why do you think a subassembly cannot cost $250 if you picked up the device for $300? just go buy another device then? what is your point? you want to buy a porsche for 20k and then you are surprised that a new gearbox is 30k???

Your tone is overly aggressive.

And I don't know how I can be clearer than in the comment you are replying to: "My point was that it reasonable to be reluctant to spend $200 to $250 to replace a small component of a device that is only worth $300."

Which part of this sentence is unclear?

Your Porshe analogy is not appropriate. If a Porsche with a working gearbox is worth 35k, then yes, I'd be reluctant to spend 30k on a gearbox alone.

the device is worth $3,000 but listed for $300 because it is used and likely has problems

I think you are talking past each other.

The grandparent’s point was that these things retailed for lots of money when new, so they make the claim that the relatively small $250 LCD repair is reasonable.

I don’t agree that this is a logical conclusion to draw - anchoring on a 30 year old sale price seems self-evidently invalid.

All I was pointing out is these things did in fact retail for $X,000, regardless of the current value.