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Overlay designations & miscellanea

I thought I'd messed up the USB lead of my HP 1020 laserjet , measuring voltages etc, trying to learn about USB function. Turned out I must have strained a USB A to B adaptor and nothing wrong with the printer. Is one rule of thumb (for a suspect USB connection) that a maximum USB insertion force of 250 gram is too low and above 450 gram is generally good ? ( I later went around a number of leads /connectors, adaptors with the kitchen scales). 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 ? 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 D13 AZZ23C8V2 Diode SOT23 dual zener 8.2V 0.3W, 3 pin related?

2 land device marked WU1 found WU BZX284-B4V3 Phi I SOD110 0.4W zener 4.3V E24 ±2%, 2 pin related ?

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

Reply to
N_Cook
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'E' is often used to indicate a connection off the board. They are probably there for automated testing in a 'Bed of Nails' (AKA: Pogo Pins) test fixture during the manufacturing process. More and more manufacturing is moving to this method where boards are handled by machines from the time the blanks are loaded into a pick & place machine, till they are ready to be installed in a product.

No. They match the component's location on the schematics and B.O.M.

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Reply to
Michael A. Terrell

On Fri, 7 May 2010 11:19:24 +0100, "N_Cook" put finger to keyboard and composed:

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?

CM1213 1, 2, 4, 6 and 8-Channel Low Capacitance ESD Protection Arrays

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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.

FWIW, this forum thread ...

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

PESD5V2S2UT Phi A SOT23 Uni-directional ESD Protection 5.2V:

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However it is a 3-pin device.

In the D132 case, it appears to be true.

13 -> 1213 2 -> -02

- Franc Zabkar

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Reply to
Franc Zabkar

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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

Reply to
N_Cook

insertion

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The "E" were not all the same physical size, one was quite large. Did not try a probe on the central material but matt black , ie non metalic. If they were in fact inductors what subclass ?, there were other items marked "L" for inductors on the same board

Reply to
N_Cook

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I wonder how we can pick up this wildcard structure as in the Philips/XNP datasheet

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in a Google search

MARKING

TYPE NUMBER / MARKING CODE PESD3V3S2UT / *U9 PESD5V2S2UT / *U1 PESD12VS2UT / *U2 PESD15VS2UT / *U3 PESD24VS2UT / *U4 Note

  • = p : made in Hong Kong.
  • = t : made in Malaysia.
  • = W : made in China.
Reply to
N_Cook

So my proper Googling for D132 ,in this case, should be of form

"D132" AND "datasheet" "part marking" OR "top code" OR "topcode" OR "top mark" OR "topmark" OR "marking"

in the searchbox

Reply to
N_Cook

On Sat, 8 May 2010 09:15:09 +0100, "N_Cook" put finger to keyboard and composed:

IMHO, adding "filetype:pdf" in place of "datasheet" would be better:

Try this:

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BTW, I have no answer to your question regarding wildcards. It appears that Google parses the asterisk instead of searching for it.

- Franc Zabkar

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

I've previously tried and failed, to find a searchengine that does not discard punctuation characters

Limiting to pdf search would fail to pick up usenet type side references

Reply to
N_Cook

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