Motorola service monitor R2670

[Frmn85]

Hello fellow Motorola experts.

We have 2 unused 2670 in the shop that i recently turned on to check status of.

Can anyone explain why the tracking generator option on 10 Mhz and 25 Mhz span produce a jagged outline when visualizing a filter/duplexer? I checked this against another Motorola 2670 service monitor and the results are the same.

Is there any thing I can do to reduce the jaggedness?

Thanks and much appreciated for any information.

 

[petnrdx]

My 2600 is the same.
Just go to the 5 mhz span.
I don't think these things had the ability to handle the wider spans
Other 2600's I have used were the same.

 

[ElroyJetson]

Components age and drift off spec. Capacitors are most likely to be the off spec components that cause the bad trace.

The TG assembly will need to be fully rebuilt.

The component degradation actually takes place more slowly when the equipment is powered up and used frequently.

Stored test equipment is soon bad test equipment. Anybody who's ever managed a shop's test gear inventory eventually learns this.

 

[Frmn85]

Thanks I will take a look at the caps but will stay at 5 Mhz in the mean time.

 

[merlin]

When caps drift for aged sitting, that effects the alignment. Everything in the 2670 is softpots you adjust from a deep menue function.
Some things you will need to realign the monitor is a detailed service manual for the 2670.
That will detail the procedure, equipment needed, and setups for re alignment.
Too many years since I touched a 2670 to recall any details.
Might be best off having Motorola re align this or find someone refurbing these that has the $100 K equipment needed.

 

[petnrdx]

BTW, my 2600 did not do decent traces on 10 mhz and 25 mhz span FROM WHEN IT WAS BRAND NEW.
The displayed traces would have "blank" spots that would "jump" from sweep to sweep.
Every one of them I ever saw did this.
So, I am not sure its a component issue.
There is a well known and trusted service person on the boards that could likely tell you exactly whether or not this
is a known "defect" or an indication of aging problems.
30 years or so (give or take) I was told that is just how the instrument works.

 

[Frmn85]

FROM WHEN IT WAS BRAND NEW.
The displayed traces would have "blank" spots that would "jump" from

Petnrdx, Thank you for this important information. seems like it is a normal issue because both service monitors have the same issue and now you are saying it comes out the box like that when it was brand new.

The 2 current 2600s were also calibrated 2017 and 2018 respectively so it was not too long ago since it was last checked.

maybe the 10 and 25 mhz span were meant for a different $$$ option or there is something more to it that is not described in the manual because i see no reason to include a 10 and 25 span that barely works.

 

[xmo]

Post a picture so we can see the extent of your issue.

The R2600 series, unlike competitive models from HP or IFR, had a local oscillator (L.O). that could only sweep over a limited range (span), so to enable spectrum analyzer spans of up to 100 MHz, the instrument sweeps a series of shorter spans and the firmware 'stitches' them together to provide the displayed wider span.

Since there is no normalization function for tracking generator measurements, response anomalies can cause irregularities at the 'stitching' sweep segment boundaries.

 

[Frmn85]

Ill get you a picture when I get in work sometime this week.

But to describe it; when Im seeing the performance of a filter such as a duplexer, the peaks and valleys show up as intermittent and repeating jagged breaks. This only happens on 10 and 25 Mhz bandwidths

Thanks!!

 

[ElroyJetson]

That says that the affected parts are probably within the 10 and 25 MHz bandwidth filter circuits. That narrows it down quite a bit.