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15_11_1 s67
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PM 3332/oL
I
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9 444 osg 82011
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cd 542
lnformation
PI T- E MA
As of eerial number D651 gome modifications bave been introórced,
a^urongst othere, to improve
the squarewave reproduction and to prevent oscillations. Hoïrever, thege modifications do not
affect the adjusting procedrre and the teónical
data. Up-to-date circuit diagrane are attached.
The principal changes are:
PHIUPS (
r
aury
Copyri3ht
Ccntrtl
Scrvicc
Printrd
in Hollend
9499 448 01901
Attenuator circuit (Fig. 231
Between input socket BUl aad blocking capacitor C26: resistot P"27 (L2 Q, L/8 W, S %).
Thé screening of. C26 ig connected to junction C26-R26 via resistor R35 (4?0 Q, L/8W, 5%1.
Chopper amplifier circuit (Fig. 24)
Transistor TS313 and resistor RÍ126 are bridged by a cera.uric capacitor C312 (1000 pF, 500 V).
On account of this and in view of a more favqrrable arrangement of parts, printed circuit
board U12 (Fig. 22) ie changed. the anode voltage of GR301 amounts to -18. ? V instead of
- 8 .7 V.
Final amplifier circuit (Fig. 25)
To imppove the HF squarewave reproduction, a series RC circult coneieting of R445 (apprc.
22 l{r, L/8 W, 5 %l and C415 (ceramic, approx. 33 pF, 500 V) is coilrested between Junctions
R432-R433 and R443-Rrt44.
The follorring parts have been added to improve tbe control range of Rl, C416 and R3:
control range Rl: resistor R425 (100t9, -1/8 W, 5%) between junctions R441-R43? and R1-C416,
control range C416: cera:nic capacitor C42O (35 pF, 500 V) in parallel with C416.
Note: R437 is mbintained.
control range R3: regigtor R430 (33 l{r, 1/8'W, 5 %) between -12 V and junction Fl427-Pl428.
The value of the voltage between the emitters of TS407 and TS408 and between the emitters of
TS409 and TS411 ig approx. 80 mV instead of 80. . .120 mV.
Moreover, some resistor values have been clpnged.
IIF and LF anplifier
circuit (Fig. 26)
To improve tle HF squarewave reproduction, a eeriee RC cirsuit consisting of R140 (appror.
L Wt,, L/8 W, 5 %l and C129 (560 pF, 500 V) has been added in parallel with R139 in the HF
arnplifier.
To improve the LF sqlr€rrewave reproduction, three series RC circuits have been added to the
LF amplifier, viz.
1. R190 (100 o, L/8 W, 5 %l nd C163 (feed-thrangh capacitor, 68 pF, 350 V) between junctiour
R191-R196 and earth,
2. PJ2L0 (12 kfl, 1/8 W, 5 %l a d C160 (plate capacitor, 68, O0O pF, 250 V) in paratlel with R211,
3. R213 (approx. 22 W2, L/8 W, 5 7ol and C165 (feed-throrgh capacitor, 1500 pF, 350 V)
between junction R2ll-emitter
TS119 and earth.
N.Y. PHILIPS' GLOETLAH?ENFAltlEÍ,EN,
Eindhoyofir Hollrnd
Ls/LL6t /t/ot
csL2762
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