Advantest R3361B Spectrum Analyzer CRT module removal and recapping.

 

DISCLAIMER: the following instructions are provided only as a report of my hobby experience. In NO way they can be interpreted as a replacement of the Advantest service  manual instructions. In no way I am responsible of any damage you or your device can suffer by following this procedure. Lethal voltages are present in the device!! Qualified personnel only! You know what you are doing and you are proceeding at your own risk!

 

 

To get to the CRT module I have followed this procedure:

1. Place the rig in normal position.
   Remove the four plastic feet on the back: the top and bottom metal covers will now slide off. You have to remove both.
2. Disconnect the black connector located in the backplane board very close to the PSU cage right front edge. It is the power and video signals BUS going to the CRT module.
3. Remove the left side rib - the one with the handle (4 big screws 4 small screws); pay attention to the plastic termination at the back side of it: slide it off BEFORE attempting to remove the rib..
   You do not need to remove the card reader board (if that option is installed).
4. Remove the plastic bar present on the upper crosspiece of the front panel and remove the 3 small screws that retain the front panel.
5. Place the rig upside-down (from now on the left and right references are referred to this new position).
6. Look at the front panel bottom crosspiece and remove the 3 small screws that retain the front panel.
   You can now pull the front panel off but to completely remove it you need disconnect the ribbon cable from the controller board and the power wires from the power switch (take note of actual connections there..).
7. The CRT module is fixed to the main frame by mean of 4 screws located at the bottom side of the box (but you see them from the top as the rig is now upside-down).
   Two are visible and reachable directly through two holes in the front panel lower crosspiece and the third is visible behind a group of wires close to back left side of the TG. Remove them all.
8. Unfortunately to reach the fourth screw you need to unlock the tracking generator. It can seems scary but it is not so difficult then...
1. Remove the bottom front crosspiece completely removing 8 big screws; note that two of them are actually fastening the TG unit front part (just under the TG output connector..).
2. Disconnect the flat cable from the back of the TG. 2 bigger and longer screws remain to be removed: they are located at the back left and right sides of the TG unit.
   At this point the TG unit can be flipped over to top of the rig (..actually the bottom ...as it is upside-down) revealing that damned fourth screw. Remove it.
9. The CRT module should now be free to come off. Take care of all the wires while removing it.
10. Once you have the CRT module in your hands, unscrew all the 8 small screws (4 on one side, 4 the on other side) but do not touch the 2 bigger screws you see on the lower back of the unit.
11. At this point you can remove the entire CRT chassis out off the metal frame.
12. Should you want to separate the board from the chassis, disconnect the two wires bundles coming from the outside; disconnect the ground lead from the circuit at the CRT neck, unscrew the 4 nuts at the bottom side of the board.
    

You are now ready for recapping and redo solder joints.
Please note that C319  (10uF/25V)is a NON-polarized electrolytic.
Here is the cap list I used for recapping:

 I've left the snubbers C319, C207, C205 and all other high voltage caps alone as I was not able to find them at local suppliers and I didn't want to wait for an online dealer..

Some useful pics:

Step 2: Video connector

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Step 8.2: damn screw

 

 

Step 8.2: flipped TG unit

 

Final test before reassembling..

 

 

Advantest R3361B Spectrum Analyzer shows two side bands 10KHz apart from 0Hz (aka: PSU recapping)

I was having fun performing some modulation measurements on my sig-gen (HP8640B) by using my R3361B as a modulation analyzer ...when started to note a tedious 10KHz AM modulation on all signals, even in CW (I mean with all 8640's modulations settings turned OFF). Using a different S.A. I verified that there is no modulation whatsoever in the 8640's CW signals. The sig-gen is not the culprit.

So I went trough section 4.3.1 of the R3361B's service manual to check the side bands around 0Hz of my S.A. Pictures show what to expect and the actual I've got. It seems like my L.O. is AM modulated @10KHz making precise measurements (low SPAN and low RBW) difficult if not impossible..

   

The problem has been fixed with a full PSU recapping. Here is the result:

 

Instructions to reach the Advantest R3361B PSU:
It is not so hard as it can seems at a first look..
You do not need to remove any board (learned the hard way...).

DISCLAIMER: the following instructions are provided only as a report of my hobby experience. In NO way they can be interpreted as a replacement of the Advantest service  manual instructions. In no way I am responsible of any damage you or your device can suffer by following this procedure. Lethal voltages are present in the device!! Qualified personnel only! You know what you are doing and you are proceeding at your own risk!

1. Leave the rig in its normal use position;
2. Remove the four plastic feet on the back: the top and bottom metal covers will now slide off. You have to remove them both;
3. Remove the left side rib - the one with the handle (4 big screws, 4 small screws); pay attention to the plastic termination at the back side of it: slide it off BEFORE attempting to remove the rib..
   Now you see the PSU cage;
4. Remove 4 screws on top of the PSU cage. Beware not leaving washers and/or screws to fall down inside the rig (they ARE NOT magnetic).
   At this point the cage top cover seems to be still fastened in some way but it is not. What is preventing you from pulling it off is some thermal conductive sticky grey material placed between the cover it self and the underlying PSU board heat sink. You can force it to come off making leverage by a large flat screwdriver.
5. Take note of wires routing and remove all 3 connectors: MAINs input, secondary outputs and FAN. Leave the yellow/black pair alone!
6. Unscrew the 4 hexagonal turrets by mean of a hexagonal socket wrench.
   The entire cage should now come off. 
7. Unscrew 2 more small screws at the bottom side of the cage and you are done: the PSU board is now free to come out in your hands.
   

I strongly recommend you to recap it all.
Here is my recapping list including what I have found inside and what I have replaced it with:

 

 

 

 

Some useful Pictures:

   

Enjoy your S.A.

Emanuele.

An Italian VOM: Chinaglia "Cortina Major"

I own one of those superb VOMs.

It features 40kOhm/Volt both in CC and AC, not a so common feature.

Googling around I realized that the schematic diagram is not available on the net.

Here it is:

Please note the galvanometer specs: 17.5uA FS!!

Enjoy.

Emanuele.