Hammond t 500 series service manual

Page 1

SECTION I HOW THE ORGAN OPERATES 1-1 GENERAL - The Hammond T-500 Organ J-s completely self-contained, requiring no external tone cabinet. The organ is equipped with two manuals, or keyboards^ of ^A keys each, a 13-note pedal keyboard, and an eKpression (swell) pedal Eor controlling output volume. Seventeen adjustable tonebara and six preset tabs enable selection of tone colors. An automatic programable rhythm unit with auto chording feature is the 1-2 diatinsuishing function of this organ froio previous T-Seriea organs. The reroainine musical variations are controlled by tablets and knobs provided. A switch (See figure 1-1 .) controls power to all motor and electronic circuits in the organ. A pilot lighc indicates when the instrument is powered, TONE SOURCE - All tones of the organ originate as electrical ,i(5stf -„¢ebu^ Mfnni cnmiBtwas inrTfffHTCBWTEHinm 1PBAl ILEKT Ul laEBIE PtH.EFlfCT& b vmt HULLIL ciuanE LOVER UNJJL ntn lErsihWD EVPHlSSKll CONIROL VHUHt Figure 1-1. Typical T-500 Organ Front View I-l

Page 2

VIBRATO Lirtf BOX mUTQ DfrUPI IU>HHIR AUTO CHOAD BOARD TREMOLi} Uhir POHIB TERMINAL PAnEL CHOSSCrtfi NETWORB EXPflESSia* PEDAL ENCtOSED REVCftBESATICM UNIT TRtMOO PlUG TONE CABINET ITECEFTAClE 'fVCiS EHAT IGN£POWa AAI FlIFER Figure 1-2, Typical T-500 Organ, Rear View signals In the tone generator assembly. It contains 74 tone ^rfieels having various numbers of teeth, with suitable gears for driving them at various speeds from a main shafc extending along the center. Each pair of tone wheels is mounted on a shaft and between them is a bakellte gear held by a coil spring forming a mechanical vibration filter. As the gear is not rigidly attached to the shaft, any pair of wheels which may be stopped accldently will not interfere with the operation of the others . Adjacent to each tone «heel is a magnetized rod with a pick-up coll wound on it. These magnets extend through the front and back of the generator, and are held by set screws which can be loosened in case adjustment is ever necessary^ Figure 1-3 shows where to find the magnet for any fre- quency number. In this drawing the dotted lines indicate frequencies ^ose tone wheels are on the same shaft. On top of the tone generator assem- bly are small transformers and condensers, forming tuned filters for the higher frequencies. They are not likely to need replacing. In case one filter becomes inopera- tive, both the transformer and condenser must be replaced with a matched set from the factory. Figure 1-^ shows the location of these filters. 1-2