Marconi TF2370 noise problem

[Dave Bullock]

Hi everyone,
Does anyone have any experience in troubleshooting the Marconi TF2370
spectrum analyser.
My unit seems to be nearly working once warmed up, but is suffering with
continuous bursts of noise 'splatter' that come and go.
If I connect the standard 10MHz output to the analyser's input and turn the
unit on, there is just a reasonably quiet noise floor. After a minute or so
the noise floor begins to increase and large bursts of 'splatter' begin to
pass through the display. After a further few minutes the 10MHz peak appears
(as it should) but is almost buried in a lower half display full of noise.
Again large bursts of noise abound almost filling the screen. If I put the
display on 'PEAK' then it fills up completely within seconds.
Just occasionally this 'elephant grass' dissappears and the unit looks to be
working normally, but never long enough to evaluate.
I have just aquired the machine and so have no experience of it working
normally.
I realise there are many mixers etc in there but could do with some pointers
like non destructive points where to disconnect the chain to isolate the
noisy module.
Thanks in anticipation.....
Dave

 

[N Cook]

Hi everyone,
Does anyone have any experience in troubleshooting the Marconi TF2370
spectrum analyser.
My unit seems to be nearly working once warmed up, but is suffering with
continuous bursts of noise 'splatter' that come and go.
If I connect the standard 10MHz output to the analyser's input and turn the
unit on, there is just a reasonably quiet noise floor. After a minute or so
the noise floor begins to increase and large bursts of 'splatter' begin to
pass through the display. After a further few minutes the 10MHz peak appears
(as it should) but is almost buried in a lower half display full of noise.
Again large bursts of noise abound almost filling the screen. If I put the
display on 'PEAK' then it fills up completely within seconds.
Just occasionally this 'elephant grass' dissappears and the unit looks to be
working normally, but never long enough to evaluate.
I have just aquired the machine and so have no experience of it working
normally.
I realise there are many mixers etc in there but could do with some pointers
like non destructive points where to disconnect the chain to isolate the
noisy module.
Thanks in anticipation.....
Dave

I repaired one once , details on my file
http://www.divdev.fsnet.co.uk/repair4.htm
I seem to remember you need to make up a board extender to work on it
it is a large repair manual probably about 300 pages
email addy on URL below

Check/re-solder/bridge all vias would be my suggestion