Sequential prophet 5 - R402 Filter Envelope Generator Time Constant.4-7; R403 Filter Envelope Amount Vca Balance; R404 Poly-Mod Filter Envelope Amount Vca Balance

4-11 R402 FILTER ENVELOPE GENERATOR TIME CONSTANT
R402 functions similarly to R401 (para. 4-10).
Start in BASIC TRIM SETUP. TABLE 4-0.
1. With DVM. probe U352-7. FILT ATK CV S/H.
2. Trigger scope from J705. SEQ TRIG OUT.
3. Set timebase to .1s/div.
4. With scope, probe U406-10. VOICE 1 FILT ENV GEN OUT.
5. On Prophets S/N 590 and above check for ENV GEN S/H Gain Modification (see SD313). The
modification adds IK resistors between U351-6/7, U352-1/2. and U352-6/7.
6. Adjust R106. FILT ATK. so the DVM reads as close to 6.250V as the quantized voltage steps will
allows. If the S/H Gain Modification has been installed, adjust R106 for a DVM reading of 6.875V.
7. Key repeatedly and measure ATK period on scope.
8. Trim R402 for 0.9-sec ATK period. Note that these trimmers have a wide range and it does not take
much movement to drastically change the TC. so be careful and go slow when trimming.
9. Probe U407-10. U408-10, U409-10 and U410-10 to trim R401s for VOICES 2 - 5. If scope is dual
trace. VOICES 2-5 can be referenced to VOICE 1.
4-12 R403 FILTER ENVELOPE AMOUNT VCA BALANCE
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Like all VCA BALs. R403 is trimmed so that with maximum CV applied, there will be no output (0.000V)
when there is no input signal.
Start in BASIC TRIM SETUP. TABLE 4-0.
1. Turn R103, FILT ENV AMT. to 10.
2. With DVM. probe U411-15. VOICE 1 FILT ENV AMT VCA.
3. Hold a key.
4. Trim R403 for 0.000-V reading. These trimmers are sensitive and it may not be possible to set
exactly 0.000V, but get as close as you can.
5. Probe U412-15. U413-15. U414-15. and U415-15 to trim R403s for VOICE 2 - 5.
4-13 R404 POLY-MOD FILTER ENVELOPE AMOUNT VCA BALANCE
R404 functions similarly to R403 (para. 4-12).
Start In BASIC TRIM SETUP. TABLE 4-0.
1. T urn R201, P-MOD FILT ENV AMT, to 10.
- 2. With DVM. probe U411-1. VOICE 1 P-MOD FILT FILT ENV AMT VCA.
3. Hold a key.
4. Trim R404 for 0.000-V reading. These trimmers are sensitive and it may not be possible to get
exactly 0.000V, but get as close as you can.
5. Probe U412-1. U413-1, U414-1, and U415-1 to trim R404s for VOICES 2 - 5.
4-14 R40S POLY-MOD OSCILLATOR B AMOUNT VCA BALANCE
R405 functions similarly to R403 (para. 4-12).
Start in BASIC TRIM SETUP. TABLE 4-0.
1. Turn R202. P-MOD OSC B AMT. to 10.
2. With DVM. probe U426-1. VOICE 1 P-MOD OSC B AMT VCA.
3. Trim R405 for 0.000-V reading.
4. Probe U421-1. U421-15. U422-1 and U422-15 to trim R405s for VOICES 2 - 5.