Dynatuner FM-1 Montaj Hizalama İşlemi İçin Talimatlar - Sayfa 16

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If the one ampere fuse blows when the set is turned on,

remove all the tubes, install another one ampere fuse and

try again.

a replacement fuse of the same size blows when

aJI of the tubes Rre removed, the trouble is either in the

wiring to the transformer's black leads, or in the transformer

itself.

If the tubes light, but not the dial light, the light may

be defective, or the wires which lead

it via the etched

circuit board may be open.

If tubes light and the eye tube shows a lighted filament,

but the eye does not have a blue-green glow on the front

screen (which is visible through the plastic insert in the

front panel) check the wiring around the tuning eye socket.

If this is all right, the fault may be in the power supply,

and the rectifier tube V9 and the associated wiring should

be checked.

the eye glows, the power supply wiring can

be asswned to be correct.

If the eye deRects as the tuning dial is turned, this is

an indication that the R.F. stages and the I.F. stages are

working. If no sound is heard, but the eye deflects, the

difficulty lies in either V7 (12AX7) or the components

associated with it, induding the volume control. If V7 is

functioning properly, touching either pin !!2 or pin

the socket with the point of a screwdriver should produce

a pop or hum through the hi fi system.

it does not, touch

the audio output cable ends when they are removed from

the tuner sockets. This will check the cable and the follow-

ing equipment. If they are working, hum will be heard when

the ca ble end is touched.

If the tuning eye does not deflect when the tuning knob

is turned, the difficulty is probably on PC-7. Tube V2

should be checked. If a very faint hiss can be heard, it is

possible that slight readjustment of the screws on top of

the tuning capacitor will bring up the signal level so that

indications are nonnal and the alignment procedure can

be begun.

Frequently difficulties in the I.F. strip (PC-8) can be

localized by touching the ,11 pin of each I.F. tube in the

sequence V6, V5, V4, V3. A noise or thud should be heard

each time the

ill

pin is touched, and the tuning eye should

deflect. If you find a

ifl

pin which does not produce a noise,

then look for the difficulty between that point and the

previously tested #1 pin.

If the tuner operates and can be aligned, but has hum in

the signal, there are several tests to be made. If there is

hum even when the volume control is turned down, unplug

the tuner from the associated equipment and see if the hum

disappears. If it does not, the fault lies in the associated

equ.ipment. If it does disappear, then the hum is most

likely to be associated with V7. The circuit should be

inspected and the 12AX7 checked, preferably by sub-

stitution. If the hum is part of the signal and disappears

when the volume is turned down, try several stations, as

it is possible that the one used as a test signal is broad-

casting some hum. If hum occurs on all stations, the

BAT8A may be faulty and should be checked (preferably

by substitution).

If there is apparent distortion in the signal, make sure

that this is not a momentary effect because of poor trans-

mission. If it persists, compare the same system with

phonograph or tape as a different program source to see

the effect can be localized to the tuner. If it is definitely in

the tuner, it may be caused by improper discriminator

alignment, and this portion of the alignment procedure

should be repeated.

In the course of trouble shooting, insped very carefully

for "bridges" of solder from one point to another. Also

recheck for correctness of component positions on t.he

,,}J

printed circuit boards. Many defects of this type, as well as -

faulty components can be ascertained by voltage measure-

ments, and a complete voltage chHrt is provided. Any

deviation of 20(,;. or more from this

chart.

is evidence of

possible defects. Examination of components in the area

of incorrect voltage (with reference to the schematic

diagram) should help to uncover

tlH~

difficult.y.

Normal radio servicing techniques of signal injection

and signal tracing are appropriate for localizing troubles,

but for best alignment, the procedure specified in these

instructions should be followed. However, if servicing is

done by a qualified technician, he can expedite alignment

by setting the

1.1<'.

transformers for peak eye defledion

using a very low kVf'1 10.7 Inc signal. The' strength of this

signal should be sufficipnt to actuate the

PYC\

but not to

close it

t.O

its normal maximum. Discriminator alignment

must foflow the technique dpscribed in tht'sl' instructions.

Conwntional SWf'ep techniquf's should not be used.

APPENDIX

Your Dynatuner as an FM

Receiver

An acc('SSory 10 watt amplifi/'r, the FMA-2, is available

to fit the multjplex adapter space on your Dynaturwr to

convert it to a complete FM receiver, requiring only a

loudspeaker. The volume control on the tuner is used, and

power is drawn from the tuner power supply. Operation as

a component tuner is not affected. FurthC'r information can

be obtained from Dynaco, Inc.

Multiplex Provisions

Your Dynatuner is fully prepared for multiplf'xed stereo

reception. The FMX·3 Dynakit Multipll'x Intf'grator can

be installed in thl' chassis cutout pl"Ovided, and tht, power

supply has heen

desi~ned

with adequate

res(~rve

for the

adapter's requiremf'nts. Most important, however, is th('

tuner's design for adequate handwidth to handle full fidelity

multiplex reception, necessitating Rat resp0I1SP well heyond

t.he audio range.

The FMX-3 Integmtor will include all necessary inter-

connection instructions. The A and B output sockets will

then provide the two stereophonic ch;:mncls, or the mono·

phonic signal when a station is not hroadcasting

steJ'(~o.

The B output socket can be connected

provide a

.75 volt isolated signal from the low impedance cathode

follower output of the discriminator without de-emphasis

for use with external multiplex adapters. For this arrange-

ment, remove the wire between the center lugs of output

sockets A and B, and connect a wire from eyelet #33 of

PC-8

the center lug of output socket

If the external

adapter contains an input blocking capacitor (.001 mfd or

greater) no other connections are required.

If the adapter does not have a blocking capacitor in

series with the input, it is generally simplest to install it in

the adapter. Alternatively, a .001 mfd capacitor can be

installed in series with the B output lead, using a one lug

terminal strip which may be bolted to the chassis with the

cover plate harclware.