HP 4957A Protocol Analyser - UK Vintage Radio Repair and Restoration Discussion Forum

rrbmachining · 5th Sep 2014, 9:05 am

I have recently acquired a faulty protocol analyser and am looking for a service manual of some kind. Internet search has not come up with anything so far so would anyone have any information on these ?

Richard Marsh.

ronbryan · 5th Sep 2014, 10:54 am

Has the Schaffner mains input filter/switch unit failed yet? It is well known source of trouble and a terrible smell.

Also the on-board Ni-Cd batteries could be faulty.

Ron

rrbmachining · 5th Sep 2014, 11:26 am

I powered it up, had it going for about 5 mins then burning smell and some muck from the rear. Really bad smell for sure. Had a quick look inside and no real signs of damage. A bit of black gunk around the mains input / switch unit. Powered it up again for a few mins and it seemed ok but have not left it on for any length of time.

dave cox · 5th Sep 2014, 2:42 pm

The answer to Ron's question is an emphatic yes !

I found the Schaffner brand filters rather expensive and found some good quality alternatives less than half the price from Farnell.

dc

mockba.the.borg · 10th Jul 2015, 9:51 pm

Hi Richard,
Did you ever find the service manuals?

I have just purchased one to work on some UART code I am writing for FPGAs, the unit is in marvellous shape, but no diskettes or any manuals.If someone could share either an image copy of the diskettes or schematic I would be very grateful.

Also, maybe I should pre-emptively change the filter just in case? Before it expels the famous black goo? Not sure what part # to look for though.

Thanks a lot and sorry for so many questions.

Thanks,
Marcelo.

woodchips · 11th Jul 2015, 7:23 pm

Manualsplus.com list them, grab quick beore they close.

5th Sep 2014, 9:05 am	#1
rrbmachining Diode Join Date: Sep 2014 Location: Burnham on Crouch, Essex, UK. Posts: 4	HP 4957A Protocol Analyser I have recently acquired a faulty protocol analyser and am looking for a service manual of some kind. Internet search has not come up with anything so far so would anyone have any information on these ? Richard Marsh. Last edited by Station X; 5th Sep 2014 at 10:36 am. Reason: Emaill address removed.

5th Sep 2014, 10:54 am	#2
ronbryan Octode Join Date: Jan 2003 Location: Guildford, Surrey, UK. Posts: 1,959	Re: HP 4957A Protocol Analyser Has the Schaffner mains input filter/switch unit failed yet? It is well known source of trouble and a terrible smell. Also the on-board Ni-Cd batteries could be faulty. Ron

5th Sep 2014, 11:26 am	#3
rrbmachining Diode Join Date: Sep 2014 Location: Burnham on Crouch, Essex, UK. Posts: 4	Re: HP 4957A Protocol Analyser I powered it up, had it going for about 5 mins then burning smell and some muck from the rear. Really bad smell for sure. Had a quick look inside and no real signs of damage. A bit of black gunk around the mains input / switch unit. Powered it up again for a few mins and it seemed ok but have not left it on for any length of time.

5th Sep 2014, 2:42 pm	#4
dave cox Nonode Join Date: Jan 2009 Location: Bristol, UK. Posts: 2,062	Re: HP 4957A Protocol Analyser The answer to Ron's question is an emphatic yes ! I found the Schaffner brand filters rather expensive and found some good quality alternatives less than half the price from Farnell. dc

10th Jul 2015, 9:51 pm	#5
mockba.the.borg Retired Dormant Member Join Date: Jul 2015 Location: Sloatsburg, New York, USA. Posts: 1	Re: HP 4957A Protocol Analyser Hi Richard, Did you ever find the service manuals? I have just purchased one to work on some UART code I am writing for FPGAs, the unit is in marvellous shape, but no diskettes or any manuals.If someone could share either an image copy of the diskettes or schematic I would be very grateful. Also, maybe I should pre-emptively change the filter just in case? Before it expels the famous black goo? Not sure what part # to look for though. Thanks a lot and sorry for so many questions. Thanks, Marcelo.

11th Jul 2015, 7:23 pm	#6
woodchips Octode Join Date: May 2010 Location: Grantham, Lincolnshire, UK. Posts: 1,174	Re: HP 4957A Protocol Analyser Manualsplus.com list them, grab quick beore they close.