Products > Test Equipment
HP 1741A oscilloscope - restoration project
bsgd:
--- Quote from: calin on January 24, 2012, 09:22:58 pm ---I just grabbed one of these in a much much better condition of an craigslist ad .. if you can believe it .... for 50$ cash !!! insane !! :) I can't wait to see how is working cause right now is resting in the trunk of my car as I am @ work :( .
--- End quote ---
Can you post some pics? Please please please ;D
mayeri:
Hi all, I has recently been registered in this site because I saw the HP 1741A restoration project. The published images reveal a very impressive professional knowledge about oscilloscopes.
Not long ago I received a similar device from my acquaintance who has not used this about five years.
Let us breathe life into the topic…
mayeri:
The storage mode seems ok…
mayeri:
These two problems with conventional mode. How do I get rid of them? Please, TekFan...
tekfan:
--- Quote from: mayeri on December 09, 2012, 06:17:37 pm ---Hi all, I has recently been registered in this site because I saw the HP 1741A restoration project. The published images reveal a very impressive professional knowledge about oscilloscopes.
Not long ago I received a similar device from my acquaintance who has not used this about five years.
Let us breathe life into the topic…
--- End quote ---
Welcome to the forum! Hope you find some useful stuff on the forum.
So, looking at the storage controls (PERSISTENCE and BRIGHTNESS) they are almost fully counterclockwise. In this case when the scope is in storage mode you should get a screen that is completely green. The trace should fade out very fast since the persistence control is almost at its minimum.
In STORAGE mode the you should get the following displays with the control settings:
PERSISTANCE min., BRIGHTNESS min. ---> CRT looks completely green
PERSISTANCE min., BRIGHTNESS max. ---> CRT looks completely green, slightly brighter trace and screen
PERSISTANCE max., BRIGHTNESS min. ---> CRT no longer green, trace is stored on the screen
PERSISTANCE max., BRIGHTNESS max. ---> CRT no longer green, stored trace is slightly brighter
Pressing the ERASE button causes the screen to flash brightly and erase the stored image
When the scope is in CONVENTIONAL mode, the screen shouldn't be green anymore and the trace should fade out almost instantly. The storage controls should have absolutely no effect in CONV mode.
What may be happening is that one of the logic ICs on the storage board is defective, causing the flood guns and storage functions to be operatied in the CONV mode. This may also be caused by leaky transistors driving the flood gun control grids, collimator plates, collector mesh, and storage mesh.
Check if the storage controls (PERSISTENCE and BRIGHTNESS) have any effect when the scope is in STORAGE and CONV mode.
Those are all the ideas I've got at the moment.
You may want to read the Theory of operation section of the service manual (onward from page 94):
http://cp.literature.agilent.com/litweb/pdf/01741-90911.pdf
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