TABLE OF CONTENTS Restoring Hammond X66 Table of

TABLE OF CONTENTS Restoring Hammond X-66 Table of Contents. Description Nbr of Slides Level Part Three. - Tone Cabinet TC 12 -77 - Addons: X-Tal Generator 5 - Addons: Stand-by PSU - Addons: Leslie Preamp - Addons: Leslie Motor Contr. - Addons: Midi on Upper Kbd 7 3 4 4 *** Part 2 *** *** 1

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 While I like the X-66 console, I'm not that enthousiastic with the TC 12 -77 concept. Seen from the outside, this tone-cabinet is rather bulky, heavy, imposing and nice. However, to my opinion, the inside is much less impressive. " TC 12 -77 was probably the last attempt of Hammond Co to compete against Leslie Co but, to my opinion, they failed and have taken a good decision to stop designing tone cabinets such as TC 12 -77 (or 10 Series) that are not at all in line with the level of X-66 console. " Of course, this is a pure personal opinion. Part 2 2

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 - Power Supply This presentation was mostly focused on X-66, so TC 12 -77 was somewhat skipped but complete technical details can be found in section 'TC 12 -77' on the website. Power Supply Unit (PSU) - The four elco's were replaced by new ones. - The four rectifier diodes in +/- 31 Vdc supply were replaced by new diodes 1 N 4720. Part 2 3

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 - Treble Amp's BEFORE The four Treble amplifiers were completely rebuilt. - Power resistors were checked and replaced when needed. - All elco's Mallory were replaced by new ones. - Germanium (Ge) transistors were replaced by Silicon (Si) ones and polarization adapted accordingly. AFTER Part 2 4

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 - Bass Amp. The Bass amplifier was also dead and completely rebuilt like the four other amp's. New resistors All Mallory cap's replaced and Si transistors installed with the needed modifications for proper bias. New elco's Part 2 5

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 - Power Amp's All power output transistors and drivers were replaced by Si ones. Additional decoupling cap's n. F) (100 New Si power transistors Part 2 6

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 - Speakers were removed and cleaned with air-pressure. After tests, one was found inoperative due to cold solder at the speaker terminal itself. Filter cap's replaced Inside the treble enclosure Part 2 7

TONE CABINET TC 12 -77 Restoring Hammond X-66 by dan. vigin REBUILDING TC 12 -77 - Bass cabinet The bass enclosure has been covered with felt material ( available from car-industry). By doing so, inside reflections are much more damped providing so a more 'velvet' sound in the low-end part of the audio spectrum. Original fiber-glass panels have been glued and stapled. Damping material Part 2 8

ADDONS: X-TAL GENERATOR Restoring Hammond X-66 by dan. vigin X-TAL GENERATOR While the original Hammond TWG is perfectly operating, an X-Tal generator has been designed and installed as a complementary generator. Quartz generator provides a better stability than AC Mains networks (at least in Europe). Instantaneous AC frequency fluctuations in the range of 1% are not unusual while average value within 24 Hrs is correct. So, even under X-Tal driven, there is always the possibilty to go back to TWG driven. Simply unplug the X-Tal connector and re-plug the 115 V connector and TWG Molex one. The X-66 console is back to original within a couple of munites. Part 2 9

ADDONS: X-TAL GENERATOR Restoring Hammond X-66 by dan. vigin X-TAL GENERATOR Herebelow is the synoptic diagram of the X-Tal generator. The heart of the system is the TOS IC. Part 2 10

ADDONS: X-TAL GENERATOR Restoring Hammond X-66 by dan. vigin X-TAL GENERATOR This drawing explains the insertion concept in X-66. Part 2 11

ADDONS: X-TAL GENERATOR Restoring Hammond X-66 by dan. vigin X-TAL GENERATOR Hereunder is a picture of the P. C. B ready for installation. TOS Synthesizer Output connector Quartz Oscillator IC Buffer stages Power supply Part 2 12

ADDONS: X-TAL GENERATOR Restoring Hammond X-66 by dan. vigin X-TAL GENERATOR Final installation near the bundle of wires coming from the TWG unit. Shielded enclosure has been added to prevent interferences of digital signals into surrounding circuits of the X-66 console. "Paralell" connecting ponits Ready for use… Detailled wiring and schematic diagrams are available on the website. This completes the X-Tal Gen. chapter Part 2 13

ADDONS: STAND-BY POWER SUPPLY Restoring Hammond X-66 by dan. vigin STAND-BY PSU. The purpose of this Stand-by PSU is simply to feed the X-66 console , the cabinet TC 12 -77 and the Leslie 145 through a Solid-State- Relay (SSR). The in-rush current can be quite high when switching ON all those equipment via the original one-pole power switch. To alleviate this situation a stand-by circuit was implemented in the console. Only a few "milliamp's" are now passing through the original power switch while the high currents are routed via the SSR. This is not a mandatory modification but 'nice to have it'. It works so since years with all my organs. Part 2 14

ADDONS: STAND-BY POWER SUPPLY Restoring Hammond X-66 by dan. vigin STAND-BY PSU. Hereunder is the schematic diagram as installed. Part 2 15

ADDONS: STAND-BY POWER SUPPLY Restoring Hammond X-66 by dan. vigin STAND-BY PSU. The Stand-by PSU is mounted in the base nearby the outlet receptacle. "Paralell" connecting ponits Power transformer Service switch +/-12 Vdc power supply board Part 2 Solid State Relay with protection. 16

ADDONS: LESLIE PREAMP Restoring Hammond X-66 by dan. vigin LESLIE PREAMP. Initially, the X-66 was not designed to be connected to Leslie cabinets. Only two 7 -pins sockets were provided to feed one or two Hammond tone cabinets. That situation is really unfortunate because while Hammond tone cabinets can reproduce typical X-66 sound ( Tabs, Percussions, Traps. . ) when playing with drawbars 'A' & 'B', we are quite far from the legendary 'Hammond sound'. The solution is to install a mixer/preamp with adequate output level to drive Leslie cabinet. The mixer/preamp was found in X-66 Service bulletins but has been recalculated with Multi. Sim V 9 simulator software. Part 2 17

ADDONS: LESLIE PREAMP Restoring Hammond X-66 by dan. vigin LESLIE PREAMP. The modifications of the initial schematic diagram are shown hereunder. Ideally the B+ voltage should be around 30 Vdc i. s. o. 24 Vdc in order to get more 'swing' at the output. The overall gain is 30 x. Tone-controls have been kept. Part 2 18

ADDONS: LESLIE PREAMP Restoring Hammond X-66 by dan. vigin LESLIE PREAMP. This picture depicts the Leslie preamp and motors control boards installed in the same metal enclosure. Leslie mixer/preamp board Leslie motors speed control board The Leslie motors speed control board is covered in the next chapter. Part 2 19

ADDONS: LESLIE PREAMP Restoring Hammond X-66 by dan. vigin LESLIE PREAMP. The Leslie preamp/motor control unit has been fixed in the base of the console. Treble level Bass level Output level Leslie motors speed control board Leslie mixer/preamp board Part 2 20

ADDONS: LESLIE MOTOR CONTROL Restoring Hammond X-66 by dan. vigin LESLIE MOTOR CONTROL The Motor Speed control involves some elements that are described hereunder. Part 2 21

ADDONS: LESLIE MOTOR CONTROL Restoring Hammond X-66 by dan. vigin LESLIE MOTOR CONTROL The Hamptone SSR-122 B requires either 'O Vdc' or 'about +10 Vdc' to switch the speed of motors. Pin #5 One 6 -pin Leslie socket has been installed in the outlet receptacle. Pin#5 of this socket is assigned to this 'Fast/Slow' motor speed control. Refer to 'Outlet Panel' for details. It is obvious that adequate modifications have to be envisaged at Leslie end as well. Part 2 22

ADDONS: LESLIE MOTOR CONTROL Pin #5 Restoring Hammond X-66 by dan. vigin LESLIE MOTOR CONTROL The block-diagram hereunder shows the different stages implemented to realize this circuit. Schematic diagram is available on the Website. Part 2 23

ADDONS: LESLIE MOTOR CONTROL Restoring Hammond X-66 by dan. vigin LESLIE MOTOR CONTROL The Motor Speed control board is installed in the same metal enclosure with Leslie preamp. Motor speed control board This completes the Leslie Motor control chapter. Part 2 24