NEC Diamond Scan 51, Service Manual

Page: 61 / 104

1. PIN 1. fmin: lower limit frequency of this setting. fmin = 5.6
×
10
8
/ (Rmin*500)
fmin = 29.1 kHz, Rmin = 18.7K
Ω
(When the frequency is 30kHz or more)
fmin = 22.8 kHz, Rmin =24K
Ω
(When the frequency is 24kHz or more)
2. PIN 2. Polarity of H/HV:
C
POL
= 0.1uf, Io =
±
1uA , Vo = 1-e-t/RC
3. H/HV synchronous input:
When there is compatibility between TTL and CMOS, the H/HV synchronous input is within
the 0.35 to 1.85 V range, and the polarity is negative.
4. Power factor control:
V4 = 0~4V = 70 to 30%, 10%/V
V4 = (Vref*R1)/R2 = 2.17V
Duty = (2.17*10%/V) + 30% = 51.7 to 56.7%
5. X-ray shutdown:
Specification: 1.65 to 1.8V shutdown
When B+ HV=25 kV, we have Vout = 25 V
DC
, therefore, when shutdown HV = 27.5 kV, we
have Vout = 30.8 V
DC
.
When R1 = 10.7K
Ω
and R2=10K
Ω
, we have shutdown VOL = 26.8 to 28.2KV.
6. Fly-back input threshold voltage:
10 Vp-p < Vin, Vcc (12V) R484 = 24K
Ω
, Vin = 11 Vp-p.
7. Horizontal drive:
Low level current: Minimum 100mA
Low level voltage: Maximum 0.4V
48.36KHz: Ton = 11.01 us, Toff = 9.66 us : 53.28%
8. Pin 10 H-PHASE control:
Control gain = 8.89% TH/V
Minimum control ROMGE =
±
22%TN
V10 = 3.8~6.8V f = 31.5 kHz, Range =
±
7.9 us
f = 64 kHz, Range =
±
3.9 us
9. Vref: Vref specification = 8.2 V
DC
10. FVC filter:
FVC = 0.052 V/kHz V11 31.5KHz to 64KHz =1.734 to 3.53V
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