Tektronix Type 130, Instruction Manual

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Replacement of Components
Replacements for all parts in the Type 130 L-C Meter can
be purchased directly from Tektronix at current prices. How-
ever, since most of the components are standard electronic
and radio parts, they can be generally be obtained locally in
less time than is required to obtain them from the factory.
Before purchasing or ordering parts, be sure to consult the
parts list to determine the tolerances and ratings required.
The parts list gives the values, tolerances, ratings and Tek -
tronix parts number for each component in the instrument.
In addition to the standard components, special parts are
manufactured by Tektronix or manufactured by other com-
panies to the Tektronix specifications. These parts and most
mechanical parts should be obtained directly from Tek-
tronix or the local Tektronix filed office, since they are
difficult or impossible to obtain from other sources.
Parts Ordering Information
You will find a serial number in the frontispiece of this
manual. This is the serial number of the instrument for
which this manual was prepared. Be sure the manual num-
ber matches the number of the instrument when you order
parts.
We make some of the changes in the instrument, the dia-
grams, parts list and manual to include the latest circuit
improvements. The hand-made changes show changes that
have been made after the printing of the manual.
Since production of your instrument, some of the
parts may have been superceded by improved components.
In such cases, the parts numbers will not be listed in your
Parts List. However, if you order a part from Tektronix and
it has been superceded by an improved component, the
new part will be shipped in place of the part ordered. Your
local Tektronix Filed Engineering Office has knowledge of
these changes and may call you if a change in your pur-
chase order is necessary. Replacement information some-
times accompanies the improved components to aid their in-
stallation.
When ordering parts, be sure to include both the descrip-
tion of the part and the 6-digit Tektronix part number
found in the Parts List. For example, if the serial number
of your Type 130 L-C Meter were 352, a certain capacitor
would be ordered as follows: C30, .001 microfarad, fixed,
mica, 500 v, 1 %, part number 283-526, for Type 130 L-C
Meter, serial Number 351.
Trouble Shooting
If the instrument fails to operate and the pilot light does
not light, check the source of ac power and see whether
the connecting cord is firmly seated. Then check the .8-
amp line fuse at the back of the instrument near the power
plug. A good way to check the fuse is to replace it with a
good one. The ac circuit to the power transformer is
completed through the RANGE SELECTOR switch. Check
the switch contacts. To make the check, you will need to
remove the case.
Some cases have side panels held in place by small
screwhead fasteners. To remove the panels, use a screwdriv-
er to rotate the fasteners approximately two turns counter -
clockwise. Then pull the upper portion of the panels out-
ward from the handle. Other cases do not have the side
panel fasteners, but the whole case is removed. To remove
this case, twist the slotted fastener, at the rear of the case,
counter-clockwise and the case will come loose. Disconnect
the power plug and you can then slide the instrument for -
ward out of the case. Cases are replaced by reversing the
order of their removal.
WARNING: The power supply furnishes 270 volts dc
across a 30-
μ
f capacitor, so be careful to avoid contact with
it when the instrument is operating.
Troubles are usually caused by tube failure, and you
can frequently correct them by simply finding the bad
tube and replacing it with a good one. However, some-
times a bad tube burns resistors or overstresses capacitors
when it fails, and in these cases you will also have to find
the bad components. Sometimes you can find them by
visual inspection.
Since troubles are usually caused by tube failure, be
sure you investigate this possibility before adjusting the in-
terior controls. One way to find bad tubes is to replace all
the tubes with good ones. If this helps the troubles, try
putting the old ones back, one at a time, until the bad tube
is discovered.
Tube failure will often show up in the voltage readings
of the power supply. So, another early step to take in look -
ing for trouble is to check the dc voltages. The two sup -
ply voltages appear conveniently at the two ends of R403,
a ceramic wire-wound resistor mounted behind the power
transformer on the same side of the chassis (see Figure 5-3).
The outside terminal should measure +150 volts ±5 volts
and the terminal nearest the chassis should read approxi-
mately 270 volts, depending on the line voltage. There is
no voltage adjustment, and if the voltages are off it is a
sign of trouble elsewhere in the circuit. The +150 volt can
be checked also at the check point indicated in Figure 5.2.