I think a lot of people here are over-thinking this. We are talking
about a linear power supply, not some super fancy microwave sauce
using ill explained magic modes of operation. Odds are good the modern
parts having higher beta and etc are not going to make things worse.
Put an equivalent load on the output of the power supply, install the
replacement "unselected" part, and see if it works by checking the
output voltage and ripple with a power resistor as a dummy load.
Assuming you know how to safely work around 120V line circuits I don't
see the harm in testing in this manner.
The only part mode where this could be out of spec and not cause
something totally obvious would be if it adds extremely low frequency
ripple you can't measure for.
If I am wrong there are other transistors of the same type in the
power supply. Take one out and measure it.
-Evan Foss
On Thu, Jun 20, 2024 at 8:03?PM Joe White via groups.io
<skinnershorse@...> wrote:
These are from the power supply board of a 3325. Per OSM they are p/n 03325-66901, 03325-66902, 03325-66903 (left to right), described as "XSTR ASSEMBLY". The manufacturer is listed as HP. I have not found the part numbers in any cross-reference lists and I have been unable to identify the parts by their markings. Any help on identifying the parts and/or replacements is greatly appreciated.
--
Joe White
KW4YW
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