AnsweredAssumed Answered

54600B triggering problem - would need the CLIP

Question asked by Jacko on Dec 22, 2008
Latest reply on Mar 2, 2009 by ko2054

Like • Show 0 Likes0
Comment • 7

Hello

My 54600B oscilloscope stopped triggering. The problem seems to be that for some reason U73 (SPT9687 video comparator) LE-input (pin 4) keeps the comparator in latched mode (Pin 4 voltage ~ -88mV and TRHYS ~ +0.36V) disabling triggering. However - I do not know why this happens. Does anybody have the circuit diagram for the trigger circuitry and/or component placement picture. All help is greatly appreciated.

BR, Jacko (oh8nj).

No one else has this question

Outcomes

7 Replies

tonykara001 Dec 22, 2008 3:25 PM
Mark Correct
Correct Answer
Search this forum for "HP 54600A Display Image Squished"

There is a CLIP link there, and the sch is probably close enough for you to figure it out.
Like • Show 0 Likes0
Actions
Jacko Dec 22, 2008 11:18 PM
Mark Correct
Correct Answer
Hi Tony

Thanks for your reply - I have checked 54600A Clip and there are similarities, but unfortunately also a lot of differences. Would especially need info on the ckt-diagram and parts layout related to U73 and it's LE/pin 4 input signal.

BR, Jacko
Like • Show 0 Likes0
Actions
ko2054 Jan 8, 2009 1:41 PM
Mark Correct
Correct Answer
Hello Jacko
First thing I would try is a two key power up. This would be the two soft keys of the six, closest to the power switch. Hold these two down and then power up. This loads the defaults for all kinds of things, including triggering. Hopefully, the trigger will come back. If not, then it is back to the schematics. Let us know if this helps or not. This is a long shot suggestion but it would be the simplest fix if it works.
Like • Show 0 Likes0
Actions
Jacko Jan 9, 2009 8:17 AM
Mark Correct
Correct Answer
Thanks for your help - unfortunately it did not help. In Auto and Auto-level triggering mode the scope does not trig and in when going to Normal-trig mode the sweep is frozen (input signal still visible) and if I push stop and run (triggering) the screen is left empty.

If I force U73 pin 4 to +5V (pin 11) via a 4.7k resistor scope trigs at once in all modes without a problem. Do you know what is the purpose of driving U73 pin 4 from a DAC with 'TRHYS' signal - to give hysteresis? In which case is it used/needed?

BR, Jacko -oh8nj
Like • Show 0 Likes0
Actions
ko2054 Jan 9, 2009 10:41 AM
Mark Correct
Correct Answer
Hello Jacko,

U73 was probably bad. When you applied 5V to the IC, you would have damaged it for sure. I think it is limited to 1.9V. Anyway, please send an email to support_col@agilent.com and address it to me and mention this is a forum question we are working on. It would help if you copied part of the message track to the email. I will need your FedEx shipping details in the email with a contact phone number. Thanks.
Like • Show 0 Likes0
Actions
kyndbo@gmail.com Mar 1, 2009 3:29 AM
Mark Correct
Correct Answer
Hi,
My HP54600B does not trig on any channel or any mode,
where can I get a clip, for the trigger circuit ?
I like the scope, its a very good tool, so I would like to spend hours to get it running,
best regard Helge
Like • Show 0 Likes0
Actions
ko2054 Mar 2, 2009 7:26 AM
Mark Correct
Correct Answer
Hello Kyndbo, you can find the CLIP for the 54600A and 54601A at http://www.home.agilent.com/agilent/edi ... id=1517718. Or, go to Agilent.com and search for 54600A and you will see a link to the 54600A CLIP. That takes you to the above link. These are scans of hardcopy material so you have to paste the pages together. I hope this helps you out.
Like • Show 0 Likes0
Actions

54600B triggering problem - would need the CLIP

Outcomes

Related Content

Recommended Content