SCA- Capacitor Board with EFB TM PC Board Assembly www.tronola.com
Thank you for purchasing our SCA- Capacitor Board with *EFB. We feel it is the single most significant upgrade you can make to your SCA-. It is designed to integrate easily into your amplifier without chassis modifications of any kind. Upgrading your SCA- with the Capacitor / EFB board consists of two stages. The first, covered in ths document, involves assembling the PC board. The second continues with installing the assembled PC board in the SCA-, and is covered in a separate installation manual.! Please note before continuing: Proper Soldering is Vital It is assumed that you posses the necessary skills and equipment to properly solder components to a printed circuit board. The majority of problems encountered after assembly are directly related to poor solder connections, such as cold joints, or solder bridges resulting in unintended connections between components. Polarized Components The electrolytic capacitors and diodes employed on the board are polar. Electrolytic capacitors have specific positive and negative leads, while diodes can only pass current in one direction, thus it is imperative that they be installed in the PC board in the correct orientation. Failure to do so can result in damage to the components, as well as failure of the board to function properly. Color Coded Components Band indicates negative (-) lead - + Electrolytic Capacitor Band indicates cathode Diode Most of the resistors on the board will be coded with colored rings which denote their value and tolerance. If you are not familiar with the color coding system it is advisable to check the value of each resistor with an ohmmeter before installing it in the board. Assembly Procedure: General Notes When installing axial components, like resistors and diodes, for neatest appearance, pre-bend the leads with small needle-nosed pliers such that the leads align with the associated holes on the board. This will also allow the components to sit flat against the board when installed. After inserting the component leads into the respective holes on the board, bend the leads outward slightly. This will prevent the component from falling out of the board when it is turned over for the soldering procedure. Install the 0.W metal film resistors R, R, R, R, R. Solder the leads to the pads and trim excess lead length. Install the W metal oxide resistors R6, R,, R, R0. Solder the leads to the pads and trim excess lead length. Install the Diodes D, D. Be sure to install the diodes in the direction indicated by the cathode band on the diodes and the board assembly diagram on page. Solder the leads to the pads and trim excess lead length. Install the Trimmer Potentiometer P. Solder the leads to the pads and trim excess lead length. www.tronola.com
Assembly Procedure Ctd. Install the Test Jacks LC, RC, COM. Solder the leads to the pads. It is not necessary to trim any excess lead length. Note: having only a single lead, the jacks will tend to fall out of the board when it is turned over to solder. You may find it helpful to secure the jacks to the top side of the board using small pieces of masking tape during the soldering process. Install the W wire wound resistor R. Solder the leads to the pads and trim excess lead length. Install the 0.uF/0V polypropyplene capacitors C, C, C. Solder the leads to the pads and trim excess lead length. Install the 0uF/0V electrolytic capacitor CD. Be sure to install in the direction indicated by the + marking on the board and the diagram on page. Solder the leads to the pads and trim excess lead length. Install the uf/0v electrolytic capacitors CA, CC. Be sure to install in the direction indicated by the + markings on the board and the diagram on page. Solder the leads to the pads and trim excess lead length. Install the.uf/v electrolytic capacitor C. Be sure to install in the direction indicated by the + marking on the board and the diagram on page. Solder the leads to the pads and trim excess lead length. Note: The lead spacing for this capacitor is very close. Be very careful to avoid creating a solder bridge between the connection pads. Confirm using a magnifying glass, if necessary. Install the 0uF/0V electrolytic capacitors CA, CB, CB. Be sure to install in the direction indicated by the + markings on the board and the diagram on page. Note that these capacitors have snap-in type leads and thus will require a little effort to press into place. Solder the leads to the pads and trim excess lead length. Mount the Voltage Regulator VR to the heatsink as shown in the diagram on page. Apply a very thin coating of silicone grease to the back side of the regulator, then tighten the mounting screw securely. It is important to keep the regulator vertical while tightening so that it will properly align with the mounting holes on the board. Install the heatsink / voltage regulator assembly on the board. Solder the large heatsink mounting lugs first, then the voltage regulator leads. Trim the excess lead length from the regulator. It will take a bit of manual dexterity to hold the heatsink flat to the board while soldering the large mounting lugs, as well as considerable heat from your soldering iron. If your iron has adjustable heat settings it is likely it will need to be set for max. and/or a larger solder tip installed. Note: The lead spacing for the regulator is very close. Be very careful to avoid creating a solder bridge between adjacent pads. Confirm using a magnifying glass, if necessary. Install the four standoffs as shown in the diagram on page. Tighten the screws securely. Assembly of the EFB / Capacitor Board is now complete. It is highly recommended that you double check your assembly, especially the orientation of the polarized capacitors and diodes. Also check carefully for solder bridges between the leads of C and VR. www.tronola.com
SCA- EFB / Capacitor Board BOM DESIG DESCRIPTION QTY. PART NUMBER VALUE/NOTES R,,, Resistor, Metal Film Mouser # -0-RC 0 Ohms / 0.W / % R Resistor, Metal Film Mouser # -K-RC K / 0.W / % R6, R Resistor, Metal Oxide Mouser # 6-0K-RC or DigiKey # 0KW--ND 0K / W/ % Resistor, Metal Oxide Mouser # 6-K-RC or K / W / % DigiKey # KW--ND R, 0 Resistor, Metal Oxide Mouser # 6-.K-RC or K / W / % DigiKey #.KW--ND R Resistor, Wirewound Mouser # -CP-J-0 or 0 Ohms / W / % Digikey # CBJB0R0-ND P Potentiometer, Trimmer Mouser # 6-6P--0LF or Digikey # 6P-0LF-ND K / 0.W / ST D, D Diode, Power, Fast Recovery Mouser # 6-UF0-E/ 000V / A Digikey # UF0-E/GICT-ND C, C, C Capacitor, Polypropylene Mouser # 66-ECW-FW0JAQ or Digikey # P-ND 0.uF / 0V / 0C C Capacitor, Electrolytic Mouser # 6-UVZVRMDD or Digikey # --ND.uF / V / 0C CA, CB, CB Capacitor, Electrolytic Mouser # 6-LGUWMELZ or Digikey # --ND 0uF / 0V / 0C CA, CC Capacitor, Electrolytic Mouser # 66-EEU-EEW0S or Digikey # P6-ND uf / 0V / 0C CD Capacitor, Electrolytic Mouser # 6-UPWHMPD6 or 0uF / 0V / 0C Digikey # -0-ND VR Voltage Regulator, Adjustable Mouser # -LMKCSE or Digikey # 6---ND LM /.A / 0C! Do not Substitute LC, RC Test Jack, Insulated, Red Mouser # 0-0-0- or Digikey # J0-ND COM Test Jack, Insulated, Black Mouser # 0-0-0- or Digikey # J-ND Heatsink, Aluminum, TO-0, Mouser # -FA-T0-E or Digikey # FA-T0-E-ND! Do not Substitute Standoff, Alum., -0 x 0. Mouser # -0 or Digikey # 0K-ND Machine Screw, -0 x / Digikey # H-ND Hex Nut, -0 x / Digikey # H6-ND Lock Washer, Internal Tooth, # Digikey # H6-ND Thermal Grease Digikey # -006-ND NOTE: In addition, you will also require four 00 ohm/0.w and four K/0.W resistors to be used in modifying the PC-0 output boards as part of the EFB implementation. These correspond to Mouser part numbers -00-RC and -K-RC respectively. If your SCA- has been, or will be, updated with PC-0A output boards, then you will also require four 0K/0.W resistors. Mouser # -0K-RC. www.tronola.com
Board Assembly -0 x / Screw # Lock Washer Standoff -0 x 0. Standoff Assembly 0.uF/0V K W C 0. VDC 0.uF/0V LC RC C COM K W CB 0uF/0V CA 0uF/0V K /W R R TM EFB Enhanced Fixed Bias BIAS ADJ 0uF 0V 0 /W 0 /W 0 /W 0 /W P K K W CA uf/0v CD R R R R R0 CB 0uF/0V CC uf/0v C LM VR.uF V SCA-EFB-R0 KV A D D R6 0.uF/0V C 0 W R R 0K W 0K W # Lock Washer -0 Hex Nut LM -0 x / Screw Thin Coating Thermal Grease Heatsink Assembly SCA- Capacitor Board with EFB TM
C A-D C 0.uF 0V (GND) (GND) C D PC- HV PC-0 HV C C R K W K W CA 0uF 0V CB 0uF 0V C 0.uF 0V VR LM C.uF V R K 0.W PC-0 6BQ HV C R0 K W CA uf 0V CB 0uF 0V C 0.uF 0V IN OUT ADJ CD 0uF 0V CW R6 R P K 0.W Bias Adj. 0K W 0K W D KV/A TS R 0R W CC uf 0V D KV/A R 0R 0.W % MF Test Jack LC Test Jack COM R 0R 0.W % MF CATH LC HUM R 0R Test Jack RC 0.W % MF CATH RC R 0R 0.W % MF SCA- Capacitor Board with EFB TM
TM Schematic of the SCA- with EFB. Modifications are shown in red. PC-0 RIGHT CHANNEL C R 6 R0 V C R R R C C0 R R R6 000 000 V 6BQ BIAS TP RC 6BQ V R R 00 00 BLU/WH /WH BLU Z-6 YEL OR 6 C 0 C 6 R TO EYELET PC- C CA C CB R R0 CA C CB IN VR OUT C ADJ CD R6 R R P BIAS ADJ. R BIAS TP COM CC D /YEL WH A SLO BLO C D 0 BRN VAC V 0 V6 V V / / V V V V BRN WH PA- CONNECT JUMPER OR CENTER SPEAKER PC-0 LEFT CHANNEL C R 6 R0 V C R R R C C0 R R R6 000 000 V 6BQ BIAS TP LC 6BQ V6 R R 00 00 BLU/WH /WH BLU Z-6 YEL OR 6 C C 0 6 R SCA- Capacitor Board with EFB TM