2032 RF levels drop from 22MHz to 1.3GHz

[Dmoff]

ive got a 2032 signal generator that works just fine till 22Mhz and then drops about 40db till 1.3Ghz. Anything before or after that range works perfect. Any ideas? thinking RF amplifier in the output stage at this point. any ideas or suggestions are much appreciated thank you

[George Edmonds]

Hi

Do you mean that you have a Marconi/IFR 2032 signal generator, without the makers name 2032 is meaningless.

There are two versions of the Marconi/IFR 2032, need the firmware version, displayed at start up, to determine which one you have.

A common problem with all Marconi/IFR instruments of the age of a 2032 is leaking/failed SMD electrolytic capacitors.

Do the standard unlock codes of 1234 and 123456 for level one and level two work, if not need both the serial number from the rear panel and the serial number displayed on start up to generate the required unlock codes.

There is a dedicated support group at Marconi-Test-Instruments@groups.io which I am the joint owner of.

G Edmonds

[Dmoff]

It is a IFR 2032, software version 9.17
Thank you for the help

[George Edmonds]

Hi

You have the later version of the main PCB,  The last version that the early PCB can use is 7.27

Do the standard unlock codes work?

Does the instrument have pulse modulation,  you can tell by if there is a blank BNC location on the top right left side of the front panel

Do you have a service manual?

G Edmonds

[Dmoff]

i have full functionality of the unit besides the rf level dropping in that range. Cal codes work, modulation is all in tolerance. Every once in awhile i can get it to not drop and it will read rf output correctly in that range but thats once every 20 tries. I do have the manual, i did put a known good attenuator in the unit and still came across the problems which led me to that amplifier possibility as ive seen that on the 2030. i plan on opening it up and inspecting the inside when i can find the time to do so.

[George Edmonds]

Hi

First the attenuator cannot be the cause of your problems.  The main problems with the attenuator are a lack of the power supply to it or the RPP (RF on/off) contacts go intermittent.

Your friend here is the block diagram (fig 4-2-1). If you look at it you will see that there is a separate  21mHz to 1.3gHz signal path on the AB3/x boards which is switched by relays.

I suspect that you have a faulty relay or a relay coil driving circuit.  At present I do not have an instrument with the RF deck cover off (many screws) but the manual drawings suggest that the relays are miniature Teledyne ones.  Expensive and getting hard to find.

G Edmonds

[Dmoff]

just wanna say thanks. looks like its going to end up being one of the relays. luckily we stock a few in the shop. Thanks for your help, we dont see alot of these signal generators so knowledge is scarce. Appreciate it