Recapping, Repairing and Maintaining Vintage Synths, Samplers and Audio Equipment

Here is some info on rebuilding power supplies (PSU) and other maintenance or repair for vintage audio gear from the ’80s and ’90s, featuring a listing of parts and often their possible modern replacements/substitutions.

Note: A lot of equipment comes in various versions. Do not take this parts list as gospel; your equipment may very well differ. Aside from the obvious variances in model numbers and/or revisions, there may also be additional errors, typos, omissions, and straight-up mistakes.

Any work performed using this list as a guide is strictly at your own risk.

In general, when replacing electrolytic capacitors on power supplies, 105 degree, low-ESR/high-ripple capacitor types are advisable. Although they are going into music equipment, audio grade brands/models like Nichicon Muse are not optimal choices for power supply maintenance.

Here are some good PSU-ready electrolytic capacitors, ranked in typical order of preference:

Panasonic FM
Panasonic FC / Nichicon HE
Nichicon PW

Selecting a higher voltage capacitor (if that’s all that can be obtained) is almost always okay, but the capacitance must be the same as the OEM component. Most of these vintage PCBs have enough extra space that the physical size of the capacitors is not of paramount concern.

E-mu Emax

E-mu Emax (PSU – Model PS-430 [Y.K. Systems, made in Korea])

** Other PSU models will differ!! **

Voltages: P1 = -12v, P2 = +12v, P3 = GND, P4 = +5v
Fuse: 250v 2A [glass] — try 530-5MF2-R

Zener Diodes
ZD1: not connected
ZD2: 5.6v Zener

Silicon Controlled Rectifier / Thyristor
SCR: S0506L, 6A OnState/IT(rms), 3.8A IT(avg), 50v VDRM, 1.5v VGT, 1.6v VTM, 6A ITM, TO220AB package (non-sensitive gate) [Teccor/Littelfuse]

** SCR, ZD2, and the glass fuse compose a “crowbar” protection circuit designed to protect the EMAX analog/digital boards **

Electrolytic Capacitors (radial)
C6/C7: 200v 100uF (85 degree) [Samyoung, high voltage!]; try 647-UPS2D101MHD (x2)
** Should be replaced simultaneously as a pair **

C11: 50v 22uF KM (105 degree) [black & tiny]; try 667-EEU-FM1H220
C16: 16v 1000uF (85 degree); try 667-EEU-FM1C102
C19: 6.3v 2200uF (85 degree); try 667-EEU-FM0J222L
C21: 16v 470uF (85 degree); ; try 667-EEU-FM1C471L

[Samyoung CERX, tall & orange, 105 degree] C15/C17/C18: 10v 1000uF; try 667-EEU-FM1A102L (x3) or 647-UHE1A102MPD6 (x3)
C20: 25v 470uF; try 667-EEU-FM1E471L

Polyester/Mylar (Poly) Capacitors
C1/C4/C5: MTK (Metallized Polyester type), 0.1uF 250v (1% tolerance)
C9: 104k, 0.1uF 630v (10% tolerance)

Ceramic Capacitors
C12: 104, 0.1uF

Rectifier Diode Bridge
D1: PBP205, bridge rectifier diode (2A, 600v, silicon) [Diotec]; try RS205L [Rectron] or NTE169 [NTE Semiconductors] or 2KBP06M-E4 [Vishay]

NPN Transistors
Q1: TIP50, NPN Silicon Transistor (5v emitter-base) [PEKOR]; try STMicroelectronics TIP50 or Fairchild TIP50
Q2: MJE13007A, NPN Silicon Bipolar Power Transistor (9v emitter-base) [PEKOR, large & thick heatsink]; try MJE13007G [ON Semiconductor]

Voltage Regulators
Q6: UA7812, 78xx series +12v output [Texas Instruments]; try 595-UA7812CKCT [TI]

PC1: CQY80n [Vishay]

Keyboard Scanner (Keyscan IC)
R1125-11 IM368 [Rockwell 6500/11]; try EPR — these are very rare outside of a board pull/donor

Programmable Array Logic
IC26: CS PAL (Chip Select); proprietary — contact R-Massive for further details
IC49: TIM PAL; proprietary — contact R-Massive for further details

SCSI Controller
IC6: NCR5380 — still easily obtainable as NOS

Aftermarket PSU Replacement
While not a direct 1:1 drop-in, the MeanWell RT-65B is worth exploring should the original PSU need to be replaced entirely instead of being rebuilt.

Roland D50

Roland D50

PSU Electrolytic Capacitors
C7/C8: 2200uF 35v; try Nichicon UHE1V222MHD (x2)
C6: 6800uF 25v; try Nichicon UPS1E682MHD
C15/C18: 47uF 25v; try Panasonic EEU-FM1E470B (x2)
C9: 47uF 16v; try Nichicon UKL1C470KEDANA
C11: 1uF 50v; try Nichicon UKL1H010KDDANA

Ensoniq Mirage

Ensoniq Mirage

PSU Electrolytic Capacitors
C16: 1000uF, 25v; try PANASONIC EEU-FM1E102
C7/12/14/15: 10uF, 35v; try NICHICON UPW1V100MDD6 (x4)
C10/20: 3300uF, 25v; try NICHICON UHE1E332MHD (x2)
C6/C17: 4700uF, 16v; try NICHICON UHE1C472MHD6 (x2)

PSU Voltage Regulators
7908 [-8v, Fairchild]; try Fairchild LM7908CT
7812c [+12v, Motorola]; try Fairchild LM7812CT
UA7805c [+5, TI]; try TI UA7805CKCS (x2!)

Ensoniq ESQm

Ensoniq ESQm

Large PSU Electrolytic Capacitors
C1/C8: 3300uF, 35V; try Nichicon UHE1V332MHD (x2)
C17/C18: 4700uF, 16V; try Nichicon UHE1C472MHD6 (x2)

Small PSU Electrolytic Capacitors
C3/C6: 10uF, 35v; try 647-UPW1V100MDD (x2)
C11/C13: 470uF, 63v; try Nichicon UHE1J471MHD6 (x2)
C15: 22uF, 16v; try UKL1C220KDDANA

Battery & Sled/Holder
CR123A 3V 1400mAh backup battery; try 658-CR123A
Holder; try 534-1051

Ensoniq VFX SD

Ensoniq VFX SD


Voltage Regulators
7912 (-12v); try Fairchild LM7912CT
7812 (+12v); try Fairchild LM7812ACT
7805 (+5v); try Fairchild LM7805ACT
National LM2925T [low drop-out regulator with delayed reset; 5-pin] (+5v, 750mA output)**

Note: There is no modern drop-in replacement for the LM2925T, so NOS is ideal. National LM2926T and ON CS8126 [TO-220 package] are other NOS or pull considerations, although all options are relatively scarce. However, it is possible to build a breadboard clone without undue stress.

Electrolytic Capacitors

C18/C14: 3300uF, 25v; try Nichicon UHE1E332MHD (x2)
C16/C19: 4700uF, 16v; try Nichicon UHE1C472MHD6 (x2)
C13: 220uF, 35v; try Panasonic EEU-FM1V221
C17/C20: 470uF, 63v; try Nichicon UHE1J471MHD6 (x2)
C15: 100uF, 35v; try Nichicon UPM1V101MPD
C2/C5/C11: 10uF, 25v; try Panasonic EEA-FC1E100 (x3)
C8: 22uF, 25v; try Panasonic EEA-FC1E220

Fuses (5x20mm, glass cartridge)

2A, 250v; try 530-5MF2-R (x2)
1.5A, 250v; 530-5MF1.5-R (x3)


Hex Inverter [Texas Instruments (TI) SN74LS04N]; try 595-SN74LS04N with a 4814-3004-CP (3M) DIP-14 socket
NCR 6500/11 MPU; try TheSoniq or Rainer Buchty — this part can almost never be found outside of robbing another display/keypad PCB


Electrolytic Capacitors

22uF, 25v [axial]; try Vishay MAL213826229E3
3.3uF, 50v [axial]; try Nichicon TVX1H3R3MAD (x12)

Battery & Sled/Holder
CR123A 3V 1400mAh backup battery; try 658-CR123A
Holder; try 534-1051

Floppy Controller
VLSI VL1772-02PC; replace with same or WD1772
DIP28 caddy/socket, 2.54mm x 15.24mm (optional); try 3M 4828-6000-CP

Serial Interface (Dual UART)
Motorola MC68681P (discontinued); NOS or chip pull suggested, or possibly Philips SCN68681C1N40

Ensoniq ESQ-1

Ensoniq ESQ1

** The ESQ1 differs from the ESQm!! **

Large PSU Electrolytic Capacitors
C1/C8: 3300uF, 25V; try Nichicon UHE1E332MHD
C17/C18: 4700uF, 16V; try Nichicon UHE1C472MHD6 (x2)

Small PSU Electrolytic Capacitors
C12: 220uF, 35V; try Panasonic EEU-FM1V221
C10: 100uF, 35V; try Nichicon UPM1V101MPD
C11/C13: 470uF, 63V; try Nichicon UHE1J471MHD6 (x2)

Linear 5K, 30mm Slide Pot (Volume or Data Entry); try Alpha 312-319B-5K

Yamaha TX16W

Yamaha TX16W

PSU Electrolytic Capacitors
47uF, 50v (x2); try Nichicon UKL1H470KPDANA
1uF, 50v (x1); try Nichicon 647-UTT1H010MDD
100uF, 200v (x2); try 647-UPS2D101MHD
1000uF, 50v (x2); try UHE1H102MHD3
2200uF, 10v (x2); try UHE1A222MHD3
1000uF, 16v (x1); try Panasonic EEU-FM1C102
470uF, 16v (x2); try Panasonic EEU-FM1C471L

Input Board Electrolytic Capacitors
10uF, 16v (x5); try Nichicon UPS1C100MDD
470uF, 6.3v (x2); try Nichicon UHV0J471MED

Casio CZ101

Casio CZ-101 / CZ-1000

DC Power Jack
(3-pin, switched type); try RAPC722X or KLDX-0202-A

Thump Eliminator Relay (SPDT 1C-style, subminiature 6-pin, through-hole/PCB, 5VDC signal relay)
OMRON G2E-187P-H-B (DC5V); try NTE R21-5D2-5/6 or HONGFA HFD41-05

NEC FZ0H473Z (5.5v, 47,000uF/0.047F); try Elna DHL-5R5D473T

Tri-state Buffer
Texas Instruments 74HC241; try 595-CD74HC241E

Electrolytic Capacitors (M4152-MA2M PCB)
3.3uF, 50v (x3); try Panasonic EEU-FC1H3R3
100uF, 6.3v; try Nichicon UVZ0J101MDD
100uF, 16v (x2); try Nichicon UKL1C101KPDANA
330uF, 16v; try Panasonic EEU-FM1C331
47uF, 16v (x2); try Nichicon UKL1C470KEDANA
1000uF, 6.3v (x2); try Panasonic EEU-FM0J102
2200uF, 16v; try Panasonic EEU-FM1C222
1uF, 50v; try Nichicon 647-UTT1H010MDD
10uF, 16v; try Nichicon UPS1C100MDD
22uF, 10v; try Nichicon 647-UPW1A220MDD
0.22uF, 50v; try Nichicon USP1HR22MDD
** This is an unusual bi-polar (no polarity) style capacitor. **

Electrolytic Capacitors (M4152-MA1M PCB)
1000uF, 6.3v (x2); try Panasonic EEU-FM0J102
47uF, 6.3v (x4); try Nichicon UVZ0J470MDD
330uF, 6.3v; try Panasonic EEU-FM0J331
470uF, 6.3v (x2); try Nichicon UVZ0J471MED
100uF, 6.3v; try Nichicon UVZ0J101MDD
3.3uF, 50v; try Panasonic EEU-FC1H3R3
1uF, 50v; try Nichicon 647-UTT1H010MDD

Casio RZ-1

Casio RZ-1

Sample Tone Knobs
10K Pots, straight side exit terminals; try Bourns 3310C-101-103L

Note: These are adequate but not quite a perfect alignment. Although they can be installed totally flush to the PCB (they will still fit and work) I would suggest keeping them off the PCB by a tiny amount so that they will be properly centered within the RZ-1 case holes upon reassembly. Measure the height of the original pot shaft for comparison, if necessary.

Additional Note: 0.125″/3.18mm flat-shaft knobs are also recommended for aesthetics. Two Grayhill 11K5019-JCNB knobs work adequately once all extra material at the mounting ends are removed (cut away and filed smooth), enabling the knobs to fit on the pot shafts more completely.

Battery Holder
CR2032 Coin Battery Holder/Clip; try 122-7520-GR

** The RZ-1 contains two similar yet different relays. **

OMRON G2E-187P-H-M 5VDC (mainboard); try NTE R21-5D2-5/6 or HONGFA HFD41-05
OMRON G2VN 237 PL 5VDC (fader board); try OMRON G5V-2-DC5

MT Jack Cable (as an external connector, *NOT* an internal jack replacement)
8-pin DIN male connector, try Kobiconn (171-0278)

PSU Electrolytic Capacitors
16V 4700uf; try Nichicon UHE1C472MHD
50v 4.7uf; try Nichicon UHE1H4R7MDD or Panasonic EEU-FC1H4R7
50V 1uf; try Nichicon UKL1H010KDDANA
50V 3.3uf; try Panasonic EEU-FC1H3R3
10V 220uf (x2); try Panasonic FM EEU-FM1A221
16V 47uf (x2); try Nichicon UKL1C470KEDANA
6.3V 470uf (x2); try Nichicon UVZ0J471MED

Larger Electrolytic Capacitors (on mainboard)
6.3V 470uf (x4), try Nichicon UVZ0J471MED

Fuses: 250V 0.5A and 125V 2A

Sockets (optional)
Numerous ICs can use DIP-28 sockets (2.54mm x 15.24mm) when being replaced; try 3M 4828-6000-CP

Yamaha SPX1000

Yamaha SPX1000

PSU Electrolytic Capacitors (radial)
C19/20/21/22: 330uF 25v; try 647-UHE1E331MPD6 (x4)
C23/24: 1000uF 10V; try 647-UHE1A102MPD6 (x2)
C11 (largest): 100uF 200v; try 647-UPS2D101MHD
C33 (smallest): 1uF 50v; try 647-UTT1H010MDD

Diodes (axial)
D6/D7: 11DQ06, Vishay schottky rectifier diodes — 60v,1.1A; try SB160-E3/54 (x2)
D8: 31DF1, Vishay fast recovery diode; try STTH302RL

Roland JX8P

Roland JX8P

PSU Electrolytic Capacitors
C1/2: 35V 4700uf, try Nichicon UPW1V472MHD (x2)
C3: 25V 6800uf, try Nichicon UPW1E682MHD
C4: 50V 1uf, try Nichicon UKL1H010KDDANA
C5/8/9: 16v 100uf, try Nichicon UKL1C101KPDANA (x3)

L/M/H Output Level and/or Memory Protect Switch
10-pin (2×5), 3-way horizontal/right-angle slide switch [SSP323-9PS, Alps]

** This is nearly impossible to find a drop-in replacement for. **

Ensoniq ASR-X

Knobs, Switches, and Encoders
Rotary Encoders (16mm); try Xicon/Alpha 318-ENC160-24P or RE160F-40E3-20A-24P
Tactile Switches (Tact Buttons); try Mountain Switch 101-0664-EV

Ensoniq ESP16+ Rack

Ensoniq EPS16+ Rack

PSU Electrolytic Capacitors
C2/10/11/13: 63V 10uF (small); try Nichicon UPW1J100MDD (x4)
C7/12: 63V 470uF (medium), try Nichicon UHE1J471MHD6 (x2)
C3/17/18: 25V 4700uF (large), try Nichicon UHE1E472MHD (x3)
C6/5: 50V 3300uF (jumbo), try Panasonic ECA-1HHG332 (x2)

Floppy Controller
VLSI VL1772-02PC; replace with same or WD1772
DIP28 caddy/socket, 2.54mm x 15.24mm (optional); try 3M 4828-6000-CP

Frontier Tango24

Frontier Tango24

PSU / AC Power Adapter
The large stock external brick-style power adapter can be replaced with a Wearnes WDS 050120 or an MG Electronics MGT-1250. Use a 2.1mm x 5mm barrel jack connector, MG Electronics MGW321MM is a convenient match with the MGT-1250.

** The power supply needs to be about 10VAC, 4A. It is NOT a DC adapter which is what makes it such an unusual and hard-to-find piece! **

Front Panel Switches
All three switches are miniature toggle switches which are vertical PCB mount (right angle, 3 pin).

[Sample Rate or Input & Output Monitor] SPDT, 2 position (ON-ON); try NKK M2012S2A2G40

[Clock Source] SPDT, 3 position (ON-OFF-ON); try NKK M2013SS1G45

DC Power Jack
(3-pin, switched type); try RAPC722X or KLDX-0202-A

Ensoniq DP/2

Ensoniq DP/2

The power supply uses an odd combination of +5V, +12V and -12V. A traditional ATX computer power supply is relatively easy to modify into a compatible PSU for the DP/2, but must be tricked into powering on and is noisier than the stock PSU because of the fan. A better option is a generic/Meanwell T-30B triple output PSU with a male DIN-6 cable attached.

Battery Holder
CR2032 Coin Battery Holder/Clip; try 122-7520-GR

Access Virus Series (A, B, C, Classic, TI, Indigo)

Knobs, Switches, and Encoders
Tactile Switches (Tact Buttons) [12x12mm, SPST, through-hole, stem height = 7.3mm, 260gf, snap-in, joint stem type]; try ALPS SKHCAC (discontinued), possible alternatives are ALPS SKQEACA010 (imperfect) or OMRON B3F-4055 (verified).

Note: OMRON B3F-4055 is a close-to-perfect replacement, but the original tact switches tend to sit ever-so-slightly higher, so it may be worthwhile to place a small, flat, thin, and non-conductive shim/riser under the tact switch prior to installation if you have a very discerning and neurotic eye. The ALPS SKQEACA010 switch absolutely needs a shim to rise it from the PCB as it will ordinarily sit noticeably lower than the stock tactile switches.

Additional Note: The plastic button tops simply pop off and snap back onto the replacement switches. DO NOT DISCARD OR LOSE THE BLACK PLASTIC BUTTON TOPPERS!!!

Rotary Knobs (ALPS 10K Linear Rotary, PCB mount); try ALPS RK11K1140A23


Knobs, Switches, and Encoders
Compression & Output Knobs (set screw type); try Davies Molding 5164-1150 (not 100% stock, but very suitable when replaced as a pair)

DOD FX96 Echo FX / Tape Delay

DC Power Jack
(3-pin, switched type); try RAPC722X or KLDX-0202-A

JBL 7110 Limiter/Compressor

Voltage Regulators
7818: standard +18V — try Fairchild (512-LM7818CT), STM, et al
7918: standard -18V — try Fairchild (512-LM7918CT), STM, et al

Relay Mute Transistor (JBL 7110 has auto bypass when not powered)
Q6: 2N6720 NPN 175V 1A Power Transistor (TO-237); try NTE 255, untested

K1: Aromat DS2E-M-DC24V DPDT Signal Relay; try Panasonic DS2E-M-DC24V or Omron G6A-274P-ST40-US-DC24

Note: K1 is known to cause signal dips and drop-outs when malfunctioning.

Electrolytic Capacitors (radial)
C43/44 (largest): 1000uF, 50V; try 667-EEU-FC1H102 or UHE1H102MHD3 (x2)
C46: 47uF, 63V; try 647-UPW1J470MPD
C47/48: 100uF, 50V; try 667-EEU-FM1H101 (x2)
C26/28: 22uF, 50V; 667-EEU-FM1H220 (x2)
C10/11/19/21/38/39/41/42/45: 10uF, 50V; try 667-EEU-FC1H100L (x9)

Note: The JBL 7110 contains a Solid State Micro SSM2014 VCE IC which is fairly difficult to obtain. Don’t be careless with it.

Trim Pot Adjustment
There are 5 trim adjustments on the 7110 PCB. Their function is glossed over in the manual, so below is a breakdown of each:

CMR TRIM ; trims common mode rejection (removing EMI/RF noise present on input jack)
RATIO TRIM ; trims ratio amp for accurate infinite compression
DISTORTION NULL ; adjusts VCA output distortion (SSM chip)
DISPLAY OFFSET ; adjusts -30dB LED turn-on point during input metering
R72 ; adjusts output metering to user taste through small front panel hole


Voltage Regulators
78M05 (+5V, 0.5a); try Fairchild LM78M05CT
79M05 (-5V, 0.5a); try Fairchild LM79M05CT
7915 (-15V, 1A+); try Fairchild LM7915CT
7815 (+15V, 1A+); try Fairchild LM7815ACT

Electrolytic Capacitors
50v 1uF (small); try 647-UHE1H010MDD
C7/10/14/17/22 — 25v 10uF (small) [x5]; try 647-UHE1H100MDD (50V rated) [x5]

50v 220uF (medium); try 667-EEU-FM1H221
35v 1000uF (large) [x2]; try 667-EEU-FM1V102 [x2]

16v 6800uF (extra large); try UHE1C682MHD

Battery Replacement
Unsolder the original and replace with just about any 3V lithium coin and a corresponding holder: CR2430, etc.

Line 6 POD Pro (also Bass POD Pro)

Front Panel Jacks
Headphone Output / Guitar Input; Neutrik NMJ6HCD2 (tested to be a perfect fit)

Note: It is recommended to heat the jack pins from the component side of the board and use a solder sucker on the underside of the PCB. Getting the rear pins clear first will facilitate lifting the jack off the PCB enough to snip the pins in order to remove the jack.

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