S3200XL backlight replacement joy

Akai S3200XL original backlight for replacement

This is Lee’s old Akai S3200XL, the man who ran off to Canada to escape drum and bass. (Maybe not strictly true, but it’ll do.)

We used it in our daft hiphop band at the end of the 90s (along with the standard issue Atari ST), but it was always a bit of a mystery to me, never having much of a chance to play with it. I half-wonder now if we could got away with using my A1200 and Octamed, which I was using for my own dodgy big beat and drum and bass. Loading times would have been a drag off floppy discs, admittedly.

Unsurprisingly Lee didn’t take it with him, so it’s bounced around a bit before it ended up with me, still wrapped in the plastic it came in and looking generally pretty clean, but just with a dark screen. The photo above was taken in a super-bright room, which doesn’t help, but it was practically invisible in low-light as well.

Let’s have a look inside:

S3200XL overview of the inside

Nowhere near as stacked up inside as the packed-out S950. Nice how it’s separated by internal walls, presumably to shield each part (power supply and floppy/motherboard/digital to analogue audio out).

Here’s the power supply – says here it’s a Cosel PMC50E-1:

S3200XL power supply

…and it looks alright? It’s not been the most heavily used box, not like my S1000, so I’m hoping that there’s plenty of life left in those caps. I’m sure I could slot in a modern 50W PSU with +5V and +/-12V outputs in if I needed to.

Here’s a closer look at the analogue out section:

S3200XL audio out

Loads of PCM61 DACs, and a couple of unused spots on the board – one for another SM5840EP digital filter, and another for an 18CV8 (?): on searching around it seems like this would be a programmable electrically erasable logic chip, which has the pleasing acronym of PEEL.

Here’s the inverter for the screen! This might actually be the culprit as to why the screen is so dull.

S3200XL inverter

Alright, enough blurry photos of the innards, we’re here to replace the backlight. I’d seen this article on replacing the backlight on a S1100 with one from iPhone 6 Plus and wondered if I could do the same for this S3200XL.

This is what we’re faced with.

S3200 taps orffffff

Love that space next to the floppy, originally meant for a magneto-optical drive. Lee just used an external Zip drive, which actually still works, although he did always take care of his stuff. Maybe we could shove a bluescsi or SCSI2SD in there.

Once the power connections on the right have been desoldered, the backlight slides out from behind the display

S3200XL power connection

Here’s the backlight, which measures 13.6cm x 4.2cm.

S3200XL backlight

The power supply connects to this distribution board – I think this connector with the red and black wires was going to the floppy drive:

S3200XL power supply connectors

Somewhere in the blur there is the connector P410 – the lower two pins have ground and +5V on them, which is perfect for powering our replacement power supply for the backlight.

I didn’t have quite the right kind of connector but this one fits anyway:

S3200XL backlight power supply connector

And here’s the XL6009 DC-DC step-up board – 5V to about 17V. In retrospect this probably should have gone on the other side of the (grounded) wall, but anyway.

S3200XL XL6009 step-up voltage converter

When it came to wiring up the connector, I killed a fair few of the backlights.

Dead iPhone 6+ connector

The connector itself is really small, and it’s extremely easy to tear it off from the rest of backlight, and equally easy to tear the wires off and pull a part of the connector with it. The wires I was adding were heavy enough by themselves to twist the connector around. It’s worth testing the backlight as working, and putting some glue on the connector; also on this one I put some of the extra protective plastic from the backlight as a backing for the connector to make it a bit stronger. I didn’t take any photos of the resulting mess.

I decided to run the +17V through a resistor and a pot to set the brightness – and here it is in the same (very) bright room as earlier – way more readable, if not amazingly bright.

S3200XL new backlight installed

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s950 screen replacement

Saturday afternoon, got a couple of hours, let’s change the screen in my S950.

Here’s the problem – backlight really dim in the late afternoon light. Even with the curtains drawn it’s hard to get a photo with the reflections. If anything this makes it look more readable than it was.

Dim looking screen on Akai S950

Let’s take it to bits.

Front panel removed from S950 to reveal buttons and original screen

I’m using the (slightly confusing) instructions from the Gearslutz Pimp my S950 thread. I bought a 40×2 display from buydisplay via Ebay – this is the one:

Stock photo of replacement display

The original screen has a 14-pin data/power connection on the left-hand side, and the backlight power connection on the right-hand side here:

Close-up of power connection on original screen

I was just interested to see what kind of voltage was appearing here, but it was hard to measure – didn’t seem to be getting anything much, maybe half-a-volt? Partly I suspected that screen is probably fine, but the inverter is stuffed – here it is, lurking in-place behind the front panel:

Power inverter for original screen - probably knackered

The connection on the left is the 5V and 0V connection from the panel – this is what we’ll use to provide the power for the backlight on the new display. The data and power connection for the display uses the bottom 14 pins on the connection, with the 15th and 16th pin taking 5V and ground respectively for the backlight.

As Don suggested in the thread, I connected a 1K pot (albeit linear, it’s all I had going spare) in series with the 5V connection to control the backlight – I nudged it down a bit from the maximum, and it’s probably a bit too bright still but it’s readable.

It took a bit of finagling to get the screen in place – it has to go behind the screw holes because the screen is thicker than the old one. The screws had to go in from the back, which was a bit of a faff.

New screen in place

Here it is with the front panel on:

S950 with front panel back on, screen glowing brightly

Looking loads better. Shame about the scratch through the screen, though not much I can do about that. It was only 75 quid when I bought it (including a massive box of discs) so I can’t complain really.

While I had it open I took some photos of the insides. Easy to see the eight voices on the top board.

View of inside S950 from the top

Getting a bit closer – loads of regulators attached to that chunky heatsink:

Top of power supply

Towards the back on the left we’ve got the power inlet, transformer and the MIDI board – PC900V opto represent.

Transformer and MIDI connection

And there’s this bit, caused me some trouble last time.

Jack board output and PCB

It’s all back together now and happily propping up a bunch of other relics.

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MPC1000 button fixing

I replaced all the small buttons on my newly acquired MPC1000 the other night, and it was dull but three hours well spent. None of the smaller buttons were much good, with the cursor keys being particularly shit.

I followed the advice in this video, and bought a bunch of Alps SKHHAKA010 switches from Farnell and warmed up the soldering iron. Credit to Farnell, they seemed to have upped their game since I started buying stuff from them – I ordered these switches at 8pm one night along with a few other bits to bump it over the free postage limit of £20, they were apparently dispatched at 9pm (“yeah right” I thought as I saw the email) and I got them the next day.

Here it is with the case off.

MPC1000 with the top popped off

Desoldering the legs of each button after I’d clipped them all out was a drag with only desoldering braid, I wished I had a better desoldering pump. Here are the dead buttons, grrr.

Dead buttons from the MPC1000

In the end it took me three hours in total, and that’s from taking it all to bits and wondering at the solid metal construction, desoldering the old buttons, fitting and soldering the new ones, and putting it all back together again.

Having spent ages looking at ideas for buttons for making my own sequencers, I liked the arrangement in use on the MPC, despite the switches themselves being rubbish. The translucent buttons have an LED just above the tact switch.

MPC button closeup

Just remains to see whether I get on with the MPC now – it’s been good fun chopping up beats with it so far, would be nice to actually finish a track with one.

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