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HP 50g & SD Cards: Performance, Format, Notes
09-03-2016, 08:53 PM (This post was last modified: 09-03-2016 09:11 PM by Vtile.)
Post: #88
RE: HP 50g & SD Cards: Performance, Format, Notes
I have interesting evening probing the 50g and using my toys.

Here is the connections between testpoints between R66, R67 and R68. Since this forum doesn't allow tables to be used in BBCode I post it as CSV to open in spreadsheet program. The measurement should be valid and my unit is working properly.

R67 is connected directly to ground and I did measure it as 17k resistor, but incircuit with normal ohms range so it might not be accurate. The continuity should be accurate, since that old measuring device is using only 25mV test voltage, so it doesn't turn silicon nor germanium devices to conducting state.

Quote:HP50g SD Card CD/WP;;;;;;
No Card;False;F;F;F;F;F
;TPG to R66;TPG to R67;TPG to R68;R66&R67;R67-R68;R66-R68
;False = NO connection;;;;;
;True = Connection;;;;;
TPG = TPGND found near battery wiring point
Measurement done without batteries (button cell included);;;;;;
Measuring device Meratronic Meratester/Conway model 639, FET Multitester ;;;;;;
;Continuity / Ohms range, test voltage 25mV / 30uW;;;;;

There is also really interesting text in that PCB seen also in your video at 17:50..

Hope this get you further.
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RE: HP 50g & SD Cards: Performance, Format, Notes - Vtile - 09-03-2016 08:53 PM

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