Marconi Aeroflex 3413 Unlevel Error 509

[CJay]

I've bought an Aeroflex IFR 3413 250KHz to 3GHz signal generator which was sold as faulty with error 509 Unlevel.

A service manual would be most welcome if anyone has a copy, I've tried Cobham/Aeroflex/IFR and while they respond to requests, so far they've been unable to supply the manual (which I believe was supplied on CD originally?)

I'm having some problems identifying the final amplifier devices, they seem to be short circuit, symptoms are that the two LT1086 regulators are dissipating *way* too much power, the output of the regulators being dragged down to ground via an almost short circuit.

Lifting the feed choke to the output devices allows the regulator output to rise to approx 11V which seems to confirm the issue.

The attached pictures (poor quality I'm afraid) shows the devices, they're marked H 1681, and the feed chokes in red.

I *think* they may be MMICs of some description but can anyone confirm that and suggest a source or alternative before I start playing with 'generic' DC to GHz MMIC devices?

[rickells]

hi,

I just acquired an Aeroflex IFR 3416 6GHz Signal Generator with an ERROR #522 and No RF output !
I believe that my unit is of the same IFR 3410 series (3410 - 3416) as your Aeroflex IFR 3414  (not 3413 ??) ?

Just started examining the unit: PS voltages and could use some help:
-- Don't know how to disassemble to get to the RF PCB board (sandwich) , any ideas ??
-- Can't find the Service Manual online and sure can't afford the $400 price that Cobham wants for it.
The Operating manual with a block diagram is on-line, but not much use.

If you are willing to email me the Service manual for this unit it would be much appreciated.

My #522 ERROR says "power supply problem; hint: RF board."
The Operating manual gives no clue.
All 9 Power LED's are Green, all 9 PCB fuses are good, and the one large in-line fuse is good.
My Supply voltages are a little low (0.2 to 0.5 V) in some instances: Not sure of the significance.
+11.81 V
+  3.35
- 11.51
+  6.49
+11.28
+11.26
+ 4.93
+ 6.48
+26.86

I can see ~ 8 Red Led's that are On, (steady On) in the RF PCB (sandwiched between the top cpu/PS/GPIB boards on Top, & the large metal sealed RF unit on the bottom.  The 8 Red Led's seem to be grouped Front: (4), (3), (1) : Back.
I have no idea what the proper disassembly sequence is to get to the RF PCB, nor how to open the Sealed RF unit correctly (many screws).

There is also a Red Blinking "Led D7+"  "Boot 0" on one of the top (CPU ?) boards (PCB barcode#  44830/367 01043 09) near IC 34, which seems to be a regulator IC of some kind. It is blinking in some sort of lengthy Morse code blinks (Short-Long-Short-Short, etc.) I have not easily been able to determine its complete sequence yet, but will soon.   

The large RF metal package on the bottom is quite hot to the touch in several places:
Possibly some short or issue inside?

Bottom Temperature position location:
Back
1   2   3   
4   5   6 
7   8   9
Front

Positions #2,3, 5,6 are very hot to the touch.

Any hints for next steps would help.
Thank you