Franc Zabkar wrote in message
...
On Fri, 7 May 2010 11:19:24 +0100, "N_Cook" put
finger to keyboard and composed:

Anyway inside the printer there were 6 unmarked 2 land SMD lumps marked
on
the overlay as E1 to E6 , is E a designation for fuse?, all were 0 ohms
across.

There were 2 unmarked green 2 land lumps on the USB lines marked VR
on the overlay, bidirectional transient suppressors ?

USB ports have short circuit current protection. I believe some may
implement this via polyswitches, or some similar device, eg PTC
resistor (?). Are these devices in series with the supply pins?

and 2 SMD contacting the USB lines marked CR, presumably rectifiers, but
can
anyone identify with more certainty

4 land device marked topmark D132
found on topcode listings

CM1213 1, 2, 4, 6 and 8-Channel Low Capacitance ESD Protection Arrays
http://www.datasheetarchive.com/pdf-...DSA-127548.pdf

Yours would be the CM1213-02Sx 2-channel array (D132 marking code). I
suspect that it would be providing ESD protection on each of the D+
and D- pins.

2 land device marked WU1

FWIW, this forum thread ...


http://www.monitorlab.ru/forum/viewt...0466ab2db337cd
6b8d9e43e15d4

... suggests that, in a HP 1020, the WU1 part may be a ...

PESD5V2S2UT Phi A SOT23 Uni-directional ESD Protection 5.2V:
http://www.nxp.com/documents/data_sh...2UT_SERIES.pdf

However it is a 3-pin device.

Generally do truncated 3 and 4 character topcodes have any relation to
the
full code ?

In the D132 case, it appears to be true.

13 - 1213
2 - -02


- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.


Thanks for that and more generally I've added
"part marking"
to "top code" "topcode" "top mark" "topmark" as synonym adjunct keywords
for SMD device coding via Google,
are there any other suggestions for more synonyms that appear in datasheets?

My sloppy typing , the WU1 is in fact 3 land