Anritsu ML524C Measuring Receiver, performance test, tear down, fault finding and repair Part 1

This is part 1 of my Anritsu ML 524C repair journey. If you not really into electronics, this video might be boring as there is a lot of tech talk and circuit analysis, essentially more to listen than to watch.
The ML524 comes in different variants with various options and is a nice little measurement receiver which covers 25MHz to 1GHz, has a built in AM/FM demodulator and a few other handy features which makes it very capable for EMC measurements.
It is 12V powered and a built in battery option was also available.
This unit is believed to be manufactured in the 90's, so it's at least 20 to 25 years old but still rather expensive if one can be found in full working order.
This receiver was quite cheap and sold to me as faulty. It came with original Operations manual and an original Service manual which do cost more than i paid for the lot. Anritsu manuals are extremely hard to find and if one turns up, they never go cheap.
I have an Anritsu ML83A Power Meter sitting on the junk pile for years but cannot find any manual, what a shame ....
The first action was checking performance of the working range (25-299MHz) which turned out to be fairly within spec.
As reported by the seller, the high range (300-1000MHz) was not working at all. It turned out that someone with rather questionable soldering skills tried to repair it, apparently that added a few more variables to the original problem.
This part shows how we narrowed the fault down to the PLL unit,
next part will show the (rather extensive) repair.
Calibration will most likely be another part as it appers to be a rather complex procedure and i'd like to have it back to full specifications wherever possible.
(c) 2017
www.dynoguy.co.uk

[@nowayjerk8064]

im noticing the lack of a testing hammer i dident even see any safety hammers ? hope you can save the receiver thanks for sharing

[@dynoguy]

lol,...thanks for watching, .. i know it's not your field but it's cold in the workshop so i'd rather stay indoors and spend some time in the radio cave.

[@nowayjerk8064]

i see the wife is opposed to hammers