HP spectrum analyser 8559A with 853A plugin - UK Vintage Radio Repair and Restoration Discussion Forum

MATTIUS · 23rd Apr 2018, 6:17 pm

Hello
I bought an HP 8559A plugin and 853A main frame on the 1st November 2017. It has been working fine up until 1 hour ago Sunday 5 pm. I have got a telescopic antenna plugged in the 50 ohm input on the front. I switched it on as normal, just wanted to check my friends mobile radio with duck antenna. I keyed the radio up on 140 MHz got a signal was OK at 40 dB on screen. Left the spectrum analyser to run for 20 mins as I had not put it on for a week was OK left it on 88 to 108 MHz broadcast band. Glanced over 30 mins later signals had gone. Scanned the band NO signals just trace line. Went down to zero 000. NO calibration line. Looped cal output 35mhz NO cal output. Gone through all the frequency ranges, there is nothing just the green line at bottom of screen, the trace line on free run. Time division on auto as usual. Frequency span 1 MHz set attention zero set ( NOTHING ). Is there anything anyone in the group forum that can suggest, anything. I would really look forward to hearing from anyone for some help, many thanks, MATTIUS .

Radio Wrangler · 23rd Apr 2018, 8:19 pm

Set the reference value down to very low levels, with wide resolution bandwidth.

Does the line lift up off the bottom and show any noise?

This gives a few clues as to whether you're chasing something in the front end or something later in the signal path.

Is there a "zero hertz" response at all?

I'v never used an 8559 at all, just an 8556 from that series, so i'm not too familiar with it.

Check the power supplies is a good starting point.

David

David

23rd Apr 2018, 6:17 pm	#1
MATTIUS Retired Dormant Member Join Date: Apr 2018 Location: Wolverhampton, West Midlands, UK. Posts: 1	HP spectrum analyser 8559A with 853A plugin Hello I bought an HP 8559A plugin and 853A main frame on the 1st November 2017. It has been working fine up until 1 hour ago Sunday 5 pm. I have got a telescopic antenna plugged in the 50 ohm input on the front. I switched it on as normal, just wanted to check my friends mobile radio with duck antenna. I keyed the radio up on 140 MHz got a signal was OK at 40 dB on screen. Left the spectrum analyser to run for 20 mins as I had not put it on for a week was OK left it on 88 to 108 MHz broadcast band. Glanced over 30 mins later signals had gone. Scanned the band NO signals just trace line. Went down to zero 000. NO calibration line. Looped cal output 35mhz NO cal output. Gone through all the frequency ranges, there is nothing just the green line at bottom of screen, the trace line on free run. Time division on auto as usual. Frequency span 1 MHz set attention zero set ( NOTHING ). Is there anything anyone in the group forum that can suggest, anything. I would really look forward to hearing from anyone for some help, many thanks, MATTIUS .

23rd Apr 2018, 8:19 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,867	Re: HP spectrum analyser 8559A with 853A pulgin Set the reference value down to very low levels, with wide resolution bandwidth. Does the line lift up off the bottom and show any noise? This gives a few clues as to whether you're chasing something in the front end or something later in the signal path. Is there a "zero hertz" response at all? I'v never used an 8559 at all, just an 8556 from that series, so i'm not too familiar with it. Check the power supplies is a good starting point. David David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done