Re: 2235 power supply noise


2213/2215A /2235/2236 AUDIBLE NOISE

REF: Mod #61544

S/N: Not available

There have been three "speakers"
identified in the 2200 Series which
emit high-frequency audible sound from
the power supply. Due to the urgency
of this change to the field, only two
of these components have been changed
on this mod. These components and new
Tektronix part numbers are as follows:

T906: Tektronix P/N 120-1439-01
C907: Tektronix P/N 285-1177-01

In a very few instruments T948 was
found to be the third culprit. Chang­ing
this part number will require UL
testing and recertification, so some
testing and evaluation need to be
conducted before the part can be modi­fied.

If an instrument comes into the Ser­vice
Center with this problem try changing
C907 first. If this does not eliminate the
sound, change T905.

T906 / T905? Is that a typo?

Barry - N4BUQ

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