This amazing looking piece of vintage kit has arrived to me in near mint, untested condition. Previous owner purchased it at a fleamarket, and put it on sale online.
The machine looks amazing!
Sadly, it does power up but no sound is heard.
I decided to take a peek inside..
Patterns matrix from under the pcbPattern matrix component sideVoice board component side
At first glance, i noticed the Toshiba silicon transistors.. expensive at the time (mid 60s? Looking at the wire resistors i would say so), usually Ace Tone units of this era used germanium transistors (cheaper but less reliable).. i thought “Yes..thats good! Quality stuff!”
2SC374 Silicon transistors
I measured the psu filtering caps.. thinking they could be the culprit.. but erm they didnt test that bad..
Upon looking closely at the board, i noticed some weird looking blobs of coloured material, crystalized?
TR29 sports a stripe because it’s used as a diode
Thats where Denon cut corners, quality wise: these are high frequency transistors (most commonly featured in transistor radios..).
Well, heres the horror part: they destroyed, one by one, at the lightest touch. I couldnt even measure them or least of all desolder them..
I took pictures of the board earlier so at least i know where the yellow and purple ones were positioned.
But alas, some trasistor places where not even populated!
Unpopulated transistor place
I made a rough note: yellow ones are 2SC183, purple ones must be 2SC182.. quite similar, with different frequency peak, NPN silicon type transistors.
As for the unpopulated places, looking at the underside of the board revealed some more unmarked, destroyed transistors-barely visible.
Solder side mounted transistors
Since schematics for this drum box are all but unavailable, i tried to contact a few people online that have/had the unit (tubbutech who has his unit on repair, reverb sellers, this page dedicated to the CRB-90, hoping someone would have taken pictures of the insides.. needing to at least understand what type of transistors populate the underside of the voice board.
Since these transistors are very fragile, my advice would be to please help and SHARE pictures of your working/faulty unit internals-my trial could be yours someday (i hope not).
While i am waiting for contribution, i am subbing the broken transistors as featured in my pictures..
2SC182 NPN silicon transistors have been subbed with BC347B, 2SC183 NPN silicon with 2N5132.
Underside of board transistors: they were mounted upside down so i was able to locate TR30: it’s yet another coloured transistor: red!
2SC475 NPN Silicon!
But it seems the carnival isnt over.. could this be TR12? Yet another transistor: GREEN, partially readable: 183? 163?
I found a blue Akai MPC1000 for cheap and i am in the process of restoring it.
The blue, old style MPC1000 has a few issues: old style pads behave erratically and the encoder has just seen better days.
The old encoder vs new encoder: the old plastic body one is impossible to find, and the new metal encoder requires you to modthe pcb to be usable.
I have installed JJOSXL on my Akai MPC1000.
The form factor differs slightly in these two encoders.. more on that later
Disassemble the Akai MPC.
Right side, front PCB. Here be most of the control buttons and encoder.Encoder solder side-bottom of PCBUsing a desoldering braid or pump, suck the solder and remove the encoder
Solder in the new one, using great care
Make sure the new encoder is flush on the pcb (slight physical difference with the old plastic one).
The pins will look like this.Make sure the encoder’s body is being pushed all the way down on all sides when soldering it in. Like so. Flush on the board.Turn the board around and CUT these tracks. There has to be no connection between the two ends. Check using your multimeter set to the buzz function.
Now using some solid core wire, make these connections:
Check if the bridges have been successfully implemented using the buzz feature on your multimeter, then reassemble.
Switch your Akai MPC on, and press MODE+the OTHER pad.
Ok so lately my DR202 has been giving me headaches.. playing drums while i was playing the bass part.
The bass was VERY low in the mix too.
I tried resetting the machine but to no avail..
BOSS DR202 reset (hard/ soft) procedure:
Power on while holding MUTE and ROLL.
Use the VALUE dial to select the settings you wish to have reset:
“ALL” = All internal settings restored to original
factory conditions.
“SongPattern” = Songs and patterns are restored
to their original conditions
(The contents of all User patterns and User songs will be erased).
“Kit” = The Kit is restored to its original
conditions.
“UtilityMIDI” = The Utility and MIDI settings are
restored to their original conditions.
3) When you have selected the settings to be reset, press TAP/ENTER twice.
The issue cold be dictated by a low internal battery issue: time to replace it
Remove knobs and alpha wheel, unscrew back cover screwsRemove the Alpha wheel encoder’s metal nutVery nice shieldingRemove internal screws and here’s the offender
Use a flat headed screwsriver to push the battery out
The RS7000 suffers from SMD caps issues: they have to be replaced on the main board.
Sometimes they blow, sometimes they fall off, sometimes they leak and sometimes they just wont work anymore-it’s a well known issue.
An RS7000 that will not boot at startup, or that only boots after some “heating up” wait is a clear sign of caps failure. I invented a word for it: twilight mode- when the green screen switches on but there are no life signs. Sometimes it just hangs at the Yamaha caption. Green screen syndrome. Twilight mode.
Here is a quick video tutorial on how to go about replacing the SMD caps from the mainboard. Just screw the back panel off and you are faced with the mainboard. Since they are surface mount caps, you can just remove them and solder some new ones in.
I would recommend using small form factor Nichicon Gold 16v caps.. replace ALL the SMD electrolytics, big and small ones.
Disclaimer: please carry out this repair only if you have electronic skills such as soldering, desoldering, handling pcbs and know how to handle electronics. Remove the mains plug on the RS7000 and use care. Do not touch the power supply components. I shall not be held responsible if you hurt yourself or other people or the machine in the process.
IMPORTANT: discharge any static you may have on you or use an antistatic vest (thats what i use) before/while doing this. Dont use wool sweaters, and take EXTRA antistatic care. Some of the electrolytics are uncomfortably close to the main ICs and processors-static can kill their functionality.
Video: how to remove electrolytic caps from the Yamaha RS7000 from their pads-recapping tutorial
Akai S1000 and its successor, S1100, are the best Akai samplers ever. They deliver a nice and punchy sound with a pronounced mid range, making drum sounds (for instance..) sit preminently in a mix.
I am using them a lot these days, making beats-based music, preferring them over the S612 and S900 for the more focused character. I decided to install a ZuluSCSI SCSI hard disk simulator so that files are handled more easily than using floppy disks..
ZuluSCSI SD card installed and ready to go
Zulu SCSI: GETTING THE SD CARD READY
WHAT SD CARD to use in the ZuluSCSI? Easy. ANY new hi speed sd card. I purchased a 32 Giga Sandisk.
Super helpful and connected seller, cheapest EU price and he’s got a direct shop that sells ZuluSCSI, accessories for the Zulu, quality LCD screens, new Meanwell power supplies for the Akai and other samplers here:
It is very important you get the dedicated flat cable from him too-this way you will not blow your Zulu if you plugged it reversed (there are reports online of similar horror stories!). On the Zulu there’s an indication for the two pins 1 and 2. On the Akai SCSI card inside the samplers theres no indication at all.. by the way the top two pins on the vertical mounted Akai card are 1 and 2.. still the connector has a nose that has to be fitting correctly to the receptacle to make a solid connection so you better take the right cable from the seller.
The ZuluSCSI gets power from the flat cable-you dont need any extra wiring. Although there is a micro usb and a male crimpconnector, you dont need them for your Akai. Leave them alone. Just the flat cable is needed.
Red stripe=pin 1Pins 1 and 2 are silkscreened on the ZuluSCSI RP2040 (top right)Thats your SCSI connector inside the Akai.. plug the flat cable in. Pins 1and 2 are the top ones.
Switch on the old behemoth and he will duly see the new SCSI hard disk.
Press FORM to format the virtual hard diskThe hard disk will then check for bad tracks. Just SKIP-it’s a waste of time.
All done.. you can now use your virtual hard disk. You will notice saves are LIGHTNING FAST. So there are a few pros to living in this horribly commercial music junk era.
I placed the Zulu vertically just to the right of the floppy disk drive using a couple of plastic self adhesive spacers-but they also sell covers to lodge it in the floppy drive’s place: they are cute and they have a receptacle to switch out sd cards easily.
POWER SUPPLY REPLACEMENT FOR THE AKAI S1100
These units have been used extensively and intensively in pro studios so the power supply of my second hand sampler was in urgent need of replacement. Ok, i decided to change the power supply for a new, more efficient one.
WARNING/DISCLAIMER: in this article i am going to describe operations that involve working with high mains voltage that could be LETHAL. It could KILL YOU. Let a professional do this kind of service for you. This is not a guide for the unexperienced. A focused state of mind when I undertook any of the actions described herein has been vital, as well as mandatory precautions such as wearing an antistatic vest, working on the sampler only when switched off and with the mains cord disconnected as well as procedures like having myself physically static discharged were followed strictly, so please do not undertake replacing the power supply if you are not used to work with mains voltage electricity. Remember: IT CAN KILL YOU. I shall not be held responsible for any damage of your sampler or any death/ wounds/ hurt to people using this article as a walkthrough to repair/service their sampler. This is just how i did it, it’s a blog post, so DO NOT USE this article as a guide.
The S1100 uses three separate voltages: 12v for the analog section, and for the digital section 12v and 5v. This article shows how i went about replacing the digital section power supply using a new transformer going from mains voltage (220v via the iec three pronged terminal) to 12 and 5 volts: the Meanwell RD-85A.
First of all, i switched off the sampler, disconnected the mains plug, and watched inside.
I highlighted the parts that i was going to use to wire the new power supply in: on top, the two mains INPUT; the lower header of four wires are the OUTPUT voltages going from the power supply to the boards
Mains disconnected and unplugged it was time to remove the old power supply.
I unscrewed the bottom and the two left hand side of the chassis screws to let the old power supply and its tray free and removed it carefully without touching the bottom of the pcb or the capacitors.The old psu.. had to go.
Next, it was time to get down to the actual business.
These go from the mains voltage to the power supply input.. CAREFUL!Push the tab underside to free the header to dislodge the mains input
I decided to use the wires already on board, so i marked them with stickers for reference of what goes where..
OUTPUT wires from the Meanwell to the boards. For colourblind people: on top, the red is the 5v, the lower, orange wire goes to 12v.Mains voltage INPUT: N is white, L is red.Reference pic indicating the actual terminals on the Meanwell.. DO NOT mix the input mains voltage red wire L with the output 5v wire.I snapped the wires as close to the crimped header as possible and put some terminal friendly lugs, insulated with heatshrinking tubes.I screwed the wires to the terminals.
All grounds are to be linked, bridged together, and they all go to the chassis ground. Since the main chassis ground is a secure, glued screw whose nut is unmovable, i decided to use a metal spacer and couple of screws to create another chassis ground, and checked for continuity with the the other stubborn dude using the multimeter’s buzz feature.
Alternate chassis ground, checked for continuity with the official one, that sits at the bottom of the machine in parallel with the IEC mains terminal, bolted to a nut.Blurry pic of the main chassis ground point.. note the green glue.
Because the power supply needs a minimum load to operate correctly, two resistors are needed across the voltage and ground of 5v and 12v, as mentioned in this tread on Gearslutz 👎🏻
These resistors are put one each between voltage and ground at the 5v and 12v terminals. Please note how i bridged the leftmost COM to the main GND on the Meanwell: all grounds are in common.
Massive looking 50 Ohms 50W resistors: USELESS
For my first test, i used a couple of 33 Ohms 10W to apply a minimum load as suggested on Gearslutz but one of them was BURNING HOT; i tried 50 Ohms 50W too and still one was overheating, so i replaced both with a 47k 5W (you will see the picture down below): MUCH BETTER!
FIRST CHECK: voltages. Without connecting the outputs, i had to see how the psu was working.. Now i had the resistors in place, i checked for continuity between all grounds and the chassis grounds, and plugged the mains, turned the power on (the IEC is connected to the sampler on off switch) and took some readings of the psu, loaded only with two resistors across the output voltages.
Checking the 5v output: nevermind the 33R resistor, read aboveNot too badChecking the 12v outputLooking good..
The trimmer on the right hand side of the Meanwell terminals can be used to adjust the two voltages (5v and 12v).. it’s a give and take science between the two outputs but in the end i had some good results.. 12v measured 12,6v and 5v measured 4,6v-the sampler works great with no overheating resistors inside!
A final test had to be carried out with the outputs in place. The moment of truth. I connected the 12v and 5v outputs to the Akai.
Thats it.. the whole shebang.
Upon switching the Akai on, all went well with some minor adjustment to be done using the trimmer: the load had changed the voltage readings sensibly, but thanks to the two resistors all went down as expected.
Next it was time to switch everything off, unplug the mains and find a way to fit the new power supply in the case.. i used the power supply original tray to hold it in place using the same screws on the bottom and side of the unit, and some wire holders, wrapped between the psu grille and some of the tray holes.
You can just about see the wire holders (green) at the bottom there.
Adding an encoder to any GOTEK unit is easy and can be very useful, especially when using the floppy drive emulator with a sampler.
I fit a GOTEK in my Ensoniq Mirage, whose drive was k.o.-lately a member of the Ensoniq Operators Facebook page has offered some cases purposedly made to fit in the Mirage-and it came with predrilled holes for screen and encoder.
To make things easier, i bought some dedicated Retro Clinic pcbs ~here~ and a couple encoders ~here~.
4 wires from the pcb to the main boardFirst solder these this wayWhite at JK, black one hole downGreen and blue like so (you can make things neater using Arduini jumper cable etc
Config file: on the Mirage usb you must let the system know there’s an ecoder-add the entry encoder=full to the configuration file (use notepad)
This ebay object offers you the chance to store your Commodore 64 floppydisks onto pc and save them for posterity.
XUM1541 (a ZOOMFLOPPY variant) uses CBM Transfer as a GUI to access the disk drive directories and act as a disk manager, writing to disk and, regardless of protections, reading and copying the disk content as a raw flux of data.
Left: serial cable input, right: micro usb output to pc. Please note the parallel male port top
At the most basic operation, the Commodore disk drive outputs data via serial cable connected to the XUM 1541, and via USB onto the pc, loading data to the CBM Xtransfer software.
If you would like to copy single files from disk, that’d suffice.
If you would rather copy entiredisks onto .d64 files, at a very convenient high speed, a parallel port mod is needed. It accesses the flux of data both from the serial and a parallel port built into the disk drive.
Open your breadbin 1541 disk drive and remove UC3
Please note if you would like to carry out this mod on a 1541-II or 1541C you’ll have to mod your units using a different guide.. This 🙂
Mount the removed ic on the new socket, hosting the male parallel port-careful with IC orientationAnd here’s the parallel mod installedMy rather crudely drilled enclosure
A very easy mod all in all, please remember to switch the devices in this order to prevent damage to the XUM and the 1541:
–FIRST connect all the cables together: serial, parallel, and USB
I am using a Flashfloppy GOTEK to read and write S612 samples onto USB.
But first, it is mandatory to send the QD drive to retirement, in great condition.
To replace the QD drive belt, you will need an appropriate belt, with a square profile
Then we will flash a GOTEK SFR1M44 using Flashfloppy.
Once done, download the latest version of Flashfloppy-you will need to copy the configuration file (FF_QD.CFG) that you will find in the /alt folder onto the USB pendrive that you are going to use with the Akai. Rename it FF.CFG and place it on the root directory of the pendrive.
We would also need a QD to Shugart interface-JazzCat sells these. Watch this:
It is mandatory to have an OLED screen to use this GOTEK setup
Connect the wires like so to the new oled screenConnect the new screen (must be less than 2” big) according to this pinout
I just got an Ensoniq Mirage.. the drive would not read my OS disk, so i dug out a blank, cheapo Gotek and flashed Flashfloppy to be my drive.
GOTEK has to be model SFRM72‑FU‑DL AKA the 720k model
After i got all my files together, i added these jumpers that allowed me to flash the Gotek
Please remember that once the flashing procedure is over, you’ll have to desolder these jumpers to use the Gotek
After the flash procedure has finished, leave only a single jumper at SO
Connect to the board, according to this picture (please note red stripe position..)
Mount using the screws located underneath the Mirage like so (they are a bit narrow for the Mirage screws so make sure you slack the gotek holes a bit)
Mono In-Stereo Out boingy greatness from Germany in a rack, possibly related with the similar Vermona spring reverb unit.
Some pics:
My second hand unit has been repaired before (burned resistor..)
This tells us the reverb tank is specced at IN 10 ohms OUT 2575 ohms
Accutronics tank
Driver circuit
Input/output/ac in board
Gutshots show this is a fairly simple unit, its driver circuit consisting of a few ics (TL072, LM380M, LM833N) some jumpers, low noise high precision resistors, OEM capacitors. Maybe its simplicity speaks for its quiet operation.
The reverb tank itself is a Fender Reverb amp compatible model, Accutronics model 9AB2C1B, medium delay (Length: 42,5cm. 3×2 springs, input impedance: 10 Ohm / DC: 0,8 Ohm, output impedance: 2575 Ohm / DC: 200 Ohm).
User service manual mod schematic repair vintage machine
Masuto's 