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8904A-04
S E R V I C E N O T E
SUPERSEDES: None
8904A Multifunction Synthesizer (Option 006/H16)

Serial Numbers: 2948A04593 / 2948A04693

Replacement of Audio Transformer to Correct Inverted Waveform

Parts Required:
9100-4833, Audio Transformer

Situation:
Some 8904A Multifunction Synthesizer (Option 006/H16) with serial numbers listed
above may have inverted OUTPUT 1 waveforms. This is because the primary of Audio
Transformer T1 was wound backwards, resulting in a 180 degree phase shift from the pri-
mary to the secondary. OUTPUT 2 waveforms are not affected.

The most noticeable waveform is the ramp because it is asymmetrical. Sinewave, square
and triangle waveforms are inverted but are less noticeable because they are symmetrical.
Normally the ramp waveform starts at the negative peak and ramps up to the positive
peak. Suspect units will exhibit an inverted ramp waveform, i.e., the ramp starts at posi-
tive peak and ramps down to the negative peak.

NOTE: Option 006/H16 is not indicated on the front panel LCD display when ann instru-
ment preset is performed. Verify if Option 006/H16 is installed by inspecting the option
labelon the rear panel of the unit.

Continued

DATE: 01 January 1992

ADMINISTRATIVE INFORMATION
SERVICE NOTE CLASSIFICATION:

MODIFICATION RECOMMENDED
ACTION IMMEDIATELY STANDARDS:
CATEGORY: ON SPECIFIED FAILURE LABOR: 1.0 Hours
AGREEABLE TIME
LOCATION CUSTOMER INSTALLABLE SERVICE RETURN USED RETURN
CATEGORY: ON-SITE INVENTORY: SCRAP PARTS: SCRAP
SERVICE CENTER SEE TEXT SEE TEXT
AVAILABILITY: PRODUCT'S SUPPORT LIFE RESPONSIBLE UNTIL: 1000 UNTIL: 01 January 1997

AUTHOR: LHL ENTITY: 1000 ADDITIONAL INFORMATION: