FIELD TEST UNIT

The Field Test Unit (FTU) is basically and offline tester.

This means that the drive cannot be selected or used by the controller while the FTU is is use. The one exception to this is that the FTU can be used to monitor head off-set while a test software routine is performing the head alignment check.

The FTU is connected to the drive in one of two ways: (1) through the standard I/O conectors on the I/O card(s) (On dual channel units the FTU may be connected to either channel I or channel II, depending on which I/O is to be checked.) or (2) through the I/O bypass connection.

The standard I/O connection requires that the system I/O cables be disconnected and that th FTU I/O cables be connected in

their place. This also reequires tat te FTU flat cable adapter cables be used. When the FTU is connected to a drive through te standard I/O connections, the drive (on channel) to which the FTU is connected, must have an I/O terminator card

installed. When the FTU is connected through the I/O the drive must be set to Online operation. However, the Local/Remote

switch AIDSI may be set tq either position depending on whether or not the drive is to be powered on from the FTU.

The I/O bypass connection leaves the system I/O cables in place and connects and I/O bypass cable between the FTU and connector A2J2 on the logic chassis backpanel. When the FTU is connected through the I/O bypass connection, the drive must be set to Offset operation.

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Specific instructions for interconnecting the drive and the FTU are contained in the preliminary set-up instructions in the FTU manual. Likewise, te procedures for causing the drive to

perform various operations (access, read, write, head selection) required for testing are contained in the FTU

manuyal. When performing the preliminary set-up procedure the drive oriented switches located on teh FTU panel shall be set as follows:

• RPM to 3600 (HI)

• TPI to 200 (LO) for BK4XX and to 400 (HI) for BK5XX

• HEADS to 5 (LO)

• BPI to 6000

The FTU also contains the head alignment card. The head

alignment card, used in conjunction with the meter on the FTU, performs the same function as the head alignemnt kit. Refer to the following paragraph for details on the head alignment kit.

HEAD ALIGNMENT KIT

The head alignment kit contains the head alignment card, the head alignment cable, and the associated null meter (refer to figure 2-1). The head alignment card develops an output

voltage which is dereived from the output of the servo and read/write preamplifiers. When a CE disk pack is installed in the drive, this output voltage will be proportional to the distance a selected head is offset from the track centerline.

the head alignment card plugs into card location A02 in the logic chassis.

The head alignment card included in the kit is either the FSV card or the AZPV card. The only difference between the cards is that the AZPV card does not have the four indicators found on the FSV card (see figure 2-1).

The following toggle switches, located on the card edge, control the cards operation:

Sl - Changes the polarity.of the alignment signal and is used in aligning both servo and read/write heads. Refer to paragraph on calculating offset in Head Alignment

procedure. (See Tests and Adjustments Section.)

S2 - When switch is in S position, the card selects the servo head as an input to the card. Wehn switch is in R/W position it selects a data head input to the card.

83 - Changes sensitivity of card. When in X.l position, the cards sensitivity is reduced by a factor of 10. ·When in Xl position, the cards sensitivity is not reduced. This switch must be in Xl position when making meaasurements for use in calculating head alignment error.

Four indicators are provided on the F8V card (but not on the AZPV card) as monitors to ensure the-card is operating properly and is receiving the proper data. These indicators are as

follows:

Power - When lighted i t indicates power is applied to card.

Input - When lighted, it indicates the input signals are too low for the alignment card circuits to operate.

Bad Track - When lighted, it indicates a short duration loss of input. A one shot maintains the lighted condition for at least four secondso Note that this indicator lights when the position of switch 81 is changed.

Mode - When lighted i t indicates that either 82 is in the S (servo) position or 83 is in the X.l position. When either of these conditions exists, read/write head alignment error cannot be measured.

The card receives its inputs through the connector in logic chassis card position A02. The Servo Dibits signal is

wirewrapped to this connector. The ground and Head Alignment Output signals are provided through the head alignment cable

which is part of the head alignment kit. This cable connects between card slot A2 (pins 08 through 11) on the wirewrap side of the logic chassis, and connector JI04 located on the head select/read amplifier card A3A02.

The output voltage of the card is measured by a null meter

which connects through test leads to test points X and Z on the card. THis meter is either part of te head alignment kit or is located on the FTU panel.

The switch on the meter's front panel changes the sensitivity of the meter. When in the 50 position, the meter read 50mV

full scale. When the switch is in the 500 position, the meter reads 500mV full scale. Tpe switch must be in thh 50 position when making measurements for use in calculating head alignment errors.

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HEAD SELECTI READ AMPLIFIER CARD

A3A02 SIDE OF CARD

\

CONNECTS TO PINS 8 THROUGH II A a^B

LOG IC CHASSIS WIREWRAP PINS

&METER IS PART OF FTU OR HEAD ALIGNMENT KIT. METER READINGS TO LEFT OF ZERO ARE NEGATIVE AND READINGS

TO RIGHT OF ZERO ARE POSITIVE.

&NEWER KITS HAVE AZPV CARD

&INDICATORS DO NOT APPEAR ON AZVP CARD 50-500

INDICATORS OBAD TRK

o^MODE