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HR-16/HR16B Service Manual 1.00 

 

3.  Avoid using adapters for two reasons. 1> Some adapters contain built in attenuators that can 

result in extremely reduced levels, both to and from the tape. 2> Oxidation and "wear and tear" 
can cause adapters to become intermittent. 

4.  Always make several copies of each "save". It's especially smart to make copies on at least 2 

different tapes as well. This reduces the chances that tape dropouts will cause loss of data. 

5.  Always use normal bias tapes, as high bias tapes actually end up recording noise, which could 

make it past the wave shaping circuitry and cause false triggers. 

6.  Always verify tapes after saving them. This helps reduce the chances of bad saves. Note 

however that the HR-16 does not compare the tape to the contents of memory. It simply verifies 
that the information on the tape is valid HR-16 data. 

7.  Experimentation with record and playback levels usually lead to better results. 
 
 

Trouble shooting tape problems should begin with listening to the data tape audibly. This can 

help the technician determine if the problem occurs during tape save or load. If unusual dropouts 
are heard then the problem is either just a bad tape, bad cable, or the tape save circuit. Normal 
sounding tapes usually indicate a tape load problem. Only practice will help you determine what is 
"normal". 
 

5.4 Tape Output 

 

The tape output hardware is simply the 8031 output port P3.2 (pin 12), a pullup resistor 

(R40), and a voltage divider (R39 and R39) for achieving a line level output. The output during tape 
save or type sync out applications will appear as a .5V pulse train, but only if the tape out is NOT 
connected to a deck (the decks A.C. coupling will distort the output). 
 

5.5 Tape Input 

 

In it's simplest form the tape input consists of an integrator (under software control of the 

8031) and a threshold detector (U1C). Input from J5 is passed through a current limiting resistor 
(R112) and on to the integrator (C11, C23, R86). The software controls the integration 
characteristics through Q16 via memory mapped I/O latch U14 (see section 3.2). While the unit is in 
'TAPE SYNC IN' mode, U14/P12 is held high, turning on Q16 and sinking the majority of current 
through the integrator to ground. This provides for faster operation of the detection circuitry. D17 is 
used to prevent leakage of the integrator signals through the control circuitry during 'TAPE 
LOAD/VERIFY' operations (when U14/P12 is low). 
 

The threshold detection circuitry surround U1C is relatively straight forward. R14 and R15 

establish the threshold level with R12 and C9 acting as a filter to stabilize the threshold level and 
prevent oscillation. R21 establishes some hysteresis and R13 is a pullup for the open collector 
output of the LM339. The output of the '339 is sent directly to the 8031 in the form of an interrupt 
line. Forcing the 8031 to respond immediately to tape input is necessary due to the timing 
constraints required for I/O (especially in tape sync situations). 
 

6.0 Test Procedures 

 

If possible, user data should always be saved (DataDisk, or equivalent, recommended) prior 

to servicing. While this may not be immediately possible (or possible at all), it should be attempted 
as soon as possible. 
 

Summary of Contents for HR-16

Page 1: ...HR 16B Drum Machine Drum Machine SERVICE MANUAL 1987 Alesis...

Page 2: ...HR 16 HR16B Service Manual 1 00 i 03 31 06 HR 16 HR 16B Drum Machines Service Manual V1 00 7 27 95...

Page 3: ...repairs done by you or with reference to the Manual shall be solely your responsibility and Alesis shall have no liability for any such repairs or service work All such service or repairs are perform...

Page 4: ...re which accompanies the product CAUTION Danger of explosion if battery is incorrectly replaced Replace only with the same type or equivalent type recommended by the equipment manufacturer Battery Man...

Page 5: ...e not to allow liquids to spill or objects to fall into any openings of the product 6 Water or Moisture The product should not be used near any water or in moisture 7 Heat Do not place the product nea...

Page 6: ...s capacitors that begin to leak excess current after a significant amount of time 5 Cable Checks Wiggling cables can reveal intermittent failures such as loose cables or poorly soldered headers Rememb...

Page 7: ...es 7 6 1 General Testing 8 6 2 Internal Diagnostics and Hidden Keys 8 6 3 DAC Adjustments 8 7 0 Updates and Corrections 9 7 1 New SRAM Supply Circuit 9 7 2 Glass Zener D15 9 7 3 Dirty Cliff jacks 10 7...

Page 8: ...Diagram 2 is provided in order to assist with board revision identification 2 0 Power Supply The power supply begins with the 9 Volt A C adapter Alesis P2 mini plug or P3 barrel types Input from J1 is...

Page 9: ...ear They should be replaced with low power versions 58256 LP when found in order to eliminate excess battery drain We are currently using Hitachi 62256ALPs as replacements CAUTION Danger of explosion...

Page 10: ...estroy any hope that the battery backup will work R28 R29 and the 5 1V zener diode D15 work together as a voltage divider to the base of Q4 and is designed so that transistor Q4 will turn on when the...

Page 11: ...is strobed At this point data on the 8031 data buss is written into the latch 3 3 Keypad I O Keypad I O is handled through a simple polling process Each row of the keypad matrix is pulled low one at a...

Page 12: ...6MHz in HR 16 DAC0 DAC16 42 51 53 60 Output to DAC A0 A19 3 17 19 23 Mask Address Buss D0 D7 61 68 Mask Rom Data Buss SNH0 39 Output Sample and Hold Control SNH1 40 SNHIN 41 Output Sample and Hold In...

Page 13: ...ts The analog equivalent of these values is compared to the actual input signals via comparators U1 pins 2 4 and 5 for the data slider and U1 pins 8 9 and 14 for the piezos The 8031 reads the result o...

Page 14: ...level output The output during tape save or type sync out applications will appear as a 5V pulse train but only if the tape out is NOT connected to a deck the decks A C coupling will distort the outpu...

Page 15: ...ivalent to reinitializing To perform the internal diagnostics connect a MIDI cable between MIDI in and out Connect a 1 8 inch cable between Tape in and out Activate the self test keys above the order...

Page 16: ...ation to install the circuit in Revision A CA PC boards while diagram 6 shows the location for revision AQ PC boards The installation of this circuit is highly recommended and is absolutely necessary...

Page 17: ...ffect was to leave the EPROM permanently enabled and use OE pin 22 which operates much faster to control it s access to the data buss On revision A PC boards this requires cutting a trace scraping the...

Page 18: ...sion CA main PC boards were manufactured with the solder mask covering the ground plane that will need to be scraped off in order to achieve a proper connection If this is not done correctly this may...

Page 19: ...f this happens then battery backup will not function The simplest solution is to lift one or both leads of the resistor slightly with a soldering iron pushing them up through from the bottom of the bo...

Page 20: ...t threshold Revision AQ During the development of the AQ main PC board one of the prime considerations was to reduce R F emissions to virtually 0 Towards this end a 100 ohm resistor R133 was introduce...

Page 21: ...vision CA When the PUP circuit first appeared it was found that the circuit would occasionally oscillate on power up causing noise This was eliminated by adding a bypass capacitor later incorporated a...

Page 22: ...ithic filter capacitor Any of the small blue RAM capacitors used as bypass capacitors can become shorted and pull the rail low We are currently using ceramic disk capacitors as replacements exclusivel...

Page 23: ...eshoot and repair as necessary No tape in Broken 1 8 jack J5 Replace and retest User error See section 5 3 Faulty 8031 Troubleshoot and repair as necessary Faulty integrator capacitor C11 or C23 Repla...

Page 24: ...ed only in the HR 16 and does not have the correct MASK ROM addressing tables to play HR 16B sounds Check and replace if necessary Faulty DM3AG ASIC Replace and retest Faulty power supply rail Trouble...

Page 25: ...N IC 74HC04 2 14 7404 1 U6 MAIN IC TL084 LF347 2 21 0084 2 U20 21 MAIN IC LM339 2 22 0339 1 U1 MAIN IC CD4052 2 23 4052 1 U19 MAIN RCA ONLY IC 6N138 2 24 0138 1 U13 MAIN IC 32Kx8 SRAM 2 17 0257 1 U12...

Page 26: ...0 00 0302 2 R28 37 MAIN RES 300K 1 8W 5 0 00 0304 1 R63 MAIN RES 3 3M 1 8W 5 0 00 0335 1 R24 MAIN RES 390K 1 8W 5 0 00 0394 1 R17 MAIN RES 470 1 8W 5 0 00 0471 13 R7 68 117 119 125 132 MAIN RES 4 7K...

Page 27: ...that would cause pattern 99 to be erased if a single pattern or song was loaded in or a cassette was verified 6 15 88 1 07 1 Fixes bug that when adding beats to the beginning of a pattern any drums m...

Page 28: ...1 64 0 50 0 1 50 58 3 OFF 0 50 0 50 Despite the displayed percentage being smaller in the new values there are actually more shuffle steps than before The old displayed percentages represented the rat...

Page 29: ...wnbeat For example if no events existed on beats 1 and 2 and the length from top was changed to be shorter by one beat the amount of silence before the first event would be wrong 2 Fixed bug which cau...

Page 30: ...transmitted or received the SYSEX ENABLE function MIDI UTIL page 15 must be turned on All 11 possible commands will be transmitted in the following format HEX COMMENTS F0H SYSTEM EXCLUSIVE STATUS BYT...

Page 31: ...of CLS HAT 0 127 0CFH MIDI note assignment of MID HAT 0 127 0D0H MIDI note assignment of OPEN HAT 0 127 0D1H MIDI note assignment of CLAPS 0 127 0D2H MIDI note assignment of PERC 3 0 127 0D3H MIDI not...

Page 32: ...minus data in 0CDH 0CEH 2D3H 2D4H DON T ALTER 2D5H Shuffle amount 0 24 0 50 2D6H 2D7H DON T ALTER 2D8H Tempo 20 255 2D9H Quant clock count must correspond to Quant value 0 9 96 64 48 32 24 16 12 8 6 1...

Page 33: ...63H 06H KICK panning bits 5 7 0 L 6 R pitch bits 0 4 0 16 1FH 15 07H SNARE sound number 0 30H 08H SNARE output assign bit 7 and volume bits 0 6 0 63H 09H SNARE panning bits 5 7 0 L 6 R pitch bits 0 4...

Page 34: ...nt or a count of clocks to wait or 0FFH which indicates the end of the pattern If the event is a drum event bit 7 will be 0 bits 4 6 will contain the dynamics of the note 0 7 and bits 0 3 will contain...

Page 35: ...H EOX 02H RECORD BUTTON This command is used to press or release the RECORD button It will affect whether the HR 16 will go into play or record when it receives a MIDI START command It does not affect...

Page 36: ...dition it is recommended that a delay be added before sending additional MIDI commands since it may take a few seconds for the copy operation to be complete during which time MIDI data will be ignored...

Page 37: ...ned off If MIDI ECHO is on the transmitting device will see the inquiry message returned to it if bi directional communication is functioning This function is useful in determining that the HR 16 is r...

Page 38: ...HR 16 HR16B Service Manual 1 00 31 12 0 Service Manual History 7 27 95 V1 00 1st release...

Page 39: ...4 15 18 D19 6 D2 1 18 D21 11 D3 1 D4 1 D5 1 15 D6 4 18 D7 2 5 D8 9 DAC 5 6 8 11 16 17 18 21 DAC0 DAC16 5 data buss 2 3 4 5 10 15 16 17 data corruption 2 3 9 data slider 6 16 17 DataDisk 7 distortion...

Page 40: ...est 8 shield 11 shorts 1 11 SHUFFLE 21 25 SIP 6 19 SNH0 5 SNH1 5 SNHIN 5 software history 15 solder mask 10 11 SONG DATA 25 26 27 28 Song Pointer 20 SRAM 1 2 3 8 9 15 16 18 SRAMs 2 9 standby current 2...

Page 41: ...HR 16 HR16B Service Manual 1 00 34 NOTES...

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