HP Logic Comparators
John Robertson, on Monday, July 28, 2003 10:41 AM wrote: ...
We do use ours on a fairly regular basis - I have the last model that would even do Tri-state 20 pin devices (buffers! 74LS244s etc.) - and as long as I double check the results it is handy to have.
I use a 16 pin version with mixed results also, but have been looking for a 20 pin BugTrap (TTL) for quite some time now. If any of you have one you'd like to part with, give me a holler. Best, - Mike -
Hi, I have bought one of these as well, and it seemed a cool idea but having read the manual it has a restricted operating frequency that's below video clock in many games. Has anyone tried using a sig-gen to replace a xtal with a slow clock and had better success with comparators as a consequence? Regards, Paul.
Chris Toseland wrote:
Hi All,
This Weekend I've been trying to use my HP Logic Comparator to help fault find some boards and am getting some very hit and miss results.
What I'd like to know is are there certain chips that this equipment won't test correctly? I know that if an output is onto a bus it'll read bad but what about simple stuff like 74ls04 it fails that then works fine with a 74ls08. It definately doesn't like 74ls283's. I have tried 3 or 4 different comparison IC's so it's not down to a bad one of them.
It even fails chips on known working boards that I'm using for signal comparison with the scope.
I'd like to use it so I can some of my backlog out of the way but it seems just to unreliable for serious fault finding.
Do I just put it down to tarnished IC legs or something? Any of you have any input?
thanks
Chris
Hmm... haven't read the manual real close yet. That would likely mean that it wouldn't work for the shift registers that I have as they're used to read playfield RAM. Shoot. JB --James Bright www.QuarterArcade.com Restored Arcade Games for your Home ----- Original Message ----- From: "Paul Swan" <pswan@lsil.com> To: "Chris Toseland" <chris.toseland@raxcosoftware.com> Cc: <techtoolslist@www.flippers.com> Sent: Monday, July 28, 2003 2:10 PM Subject: Re: HP Logic Comparators
Hi,
I have bought one of these as well, and it seemed a cool idea but having read the manual it has a restricted operating frequency that's below video clock in many games.
Has anyone tried using a sig-gen to replace a xtal with a slow clock and had better success with comparators as a consequence?
Regards,
Paul.
Chris Toseland wrote:
Hi All,
This Weekend I've been trying to use my HP Logic Comparator to help fault find some boards and am getting some very hit and miss results.
What I'd like to know is are there certain chips that this equipment won't test correctly? I know that if an output is onto a bus it'll read bad but what about simple stuff like 74ls04 it fails that then works fine with a 74ls08. It definately doesn't like 74ls283's. I have tried 3 or 4 different comparison IC's so it's not down to a bad one of them.
It even fails chips on known working boards that I'm using for signal comparison with the scope.
I'd like to use it so I can some of my backlog out of the way but it seems just to unreliable for serious fault finding.
Do I just put it down to tarnished IC legs or something? Any of you have any input?
thanks
Chris
I have dropped other crystals in to slow boards down, but there are limits to how slow you can go for CPUs and Dynamic RAM... Works fine for TTL only boards though. John :-#)# At 11:10 AM 28/07/2003 -0700, Paul Swan wrote:
Hi,
I have bought one of these as well, and it seemed a cool idea but having read the manual it has a restricted operating frequency that's below video clock in many games.
Has anyone tried using a sig-gen to replace a xtal with a slow clock and had better success with comparators as a consequence?
Regards,
Paul.
Chris Toseland wrote:
Hi All,
This Weekend I've been trying to use my HP Logic Comparator to help fault find some boards and am getting some very hit and miss results.
What I'd like to know is are there certain chips that this equipment won't test correctly? I know that if an output is onto a bus it'll read bad but what about simple stuff like 74ls04 it fails that then works fine with a 74ls08. It definately doesn't like 74ls283's. I have tried 3 or 4 different comparison IC's so it's not down to a bad one of them.
It even fails chips on known working boards that I'm using for signal comparison with the scope.
I'd like to use it so I can some of my backlog out of the way but it seems just to unreliable for serious fault finding.
Do I just put it down to tarnished IC legs or something? Any of you have any input?
thanks
Chris
participants (6)
-
Chris Toseland -
James S. Bright -
John Robertson -
Kev -
Mike Haaland -
Paul Swan