Marconi 2023A Signal generator

[Wendymott]

Hi Peeps. Yes I am going to throw myself on your mercy..... Ok I trusted the vendor to sell a tested working item. Today I received the above item. Was NOT a paltry cost. Plugged it in. Error message with most things I tried...... Err 173. Now I dont have the manual, and I wondered if any member has the info.

I have not contacted the vendor YET..as I would like to keep it IF I can get it to work.
Yours hopefully
Wendy

[Station X]

Try this group:-

https://groups.io/g/Marconi-Test-Instruments/topics

[Station X]

See here:-

http://www.ko4bb.com/getsimple/index...ls&dir=Marconi

[Dickie]

Hi,

Error 173 says "units not valid" according to the handbook, which could mean anything. I have both the operating and servicing manuals, which are way too big to post here. Drop me a pm with your email address.
I would strongly advise not doing anything to this before finding out what the seller is prepared to do in the way of a partial refund.

Edit: Sorry, crossed with Graham.

[Dickie]

Couldn't find the 2023A operating handbook on the Ko4bb site, so I've uploaded my copy. Also here for anyone who needs it:

[Wendymott]

Thanks Graham.. I tried a request to join..but nothing has happened as yet.

[Wendymott]

Hey peeps..Wow. Thanks all that replied. I downloaded the Service Manual... Hmm Dickie.. I was slightly tempted to open it up and see if anything had moved in transit. But as the display shows the identical photo to the one on ebay.. I decided it travelled ok. I have sent the vendor a note, telling them I am not a happy bunny. Lets see where it goes. But I am NOT paying return postage, as it arrived faulty. Re error message 173.. I can find no reference to that number.. unless I have not gone far enough,

[Dickie]

Error 173 is listed on page 4-57 of the operating handbook. No offence intended, but it could be finger trouble?

[G0HZU_JMR]

I'm a long time user of these sig gens at work and I've got the 2024 version here at home.

Error 173 isn't something I've seen before and it isn't obvious how to generate this error by entering incorrect units. However, the button membrane on these sig gens is a bit dodgy so maybe you could try switching it off and then press every button on the front panel several times to see if any of the buttons is a bit sticky and has partially stuck on. It may be that the sig gen thinks one of its front panel buttons is being pressed all the time.

Try wiggling all the buttons and then power it on again and see if things are better.

One other thing, these sig gens are protected by two levels of password security. The default Lev1 and Lev2 passwords are 123 and 123456. However, it is possible to change these to a unique password (probably not wise).

if someone has changed the level 2 password then you won't be able to adjust some aspects of the advanced sig gen settings to do with user calibration etc.

Fortunately, these sig gens also have a factory password that is unique to the serial number and this can override the Lev2 password and allow you to set it back to 123456. George at the Marconi Groups can get the factory password for you if you give him the serial number.

[G0HZU_JMR]

The other thing is that these sig gens have lots of memory storage to allow dozens of favourite user settings.

If someone has tried to store something in memory that has the wrong units then maybe this could cause error 173? There is a document that explains how to clear the user memory slots but you need Lev2 access via the Lev2 password to do this.

See attached. Make sure you don't erase the calibration data though!

There are also at least two versions of the service manual available online.

[Wendymott]

Hi Richard. I must say... well hidden Marconi... or who or whom wrote the manual. Error messages are in section 5...... So I had bypassed section 4.
So I see.. 173 exe Units not valid .
YES you are correct Richard. After a read of the User Manual. I do find the item is now functioning as expected. Although in my defence.. its not intuitive. Thanks for your input.

[Wendymott]

Hi Jeremy. Sorry I missed your inputs. I think the errors are ALL Mine...I will do as you suggest though...The Vendor was VERY Good with me, even offering to replace with a more expensive model.. however I do not want something for nothing... "I do really" but its not what I do. Just got to rejig the RF shelf now.

[G0HZU_JMR]

Maybe you have different firmware to me. I tried all kinds of illegal unit entries on mine and none gave error 173. I got several other error codes but not 173.

[G0HZU_JMR]

If you do go on the Marconi Groups for general advice about this sig gen they may advise you to replace the PSU caps. There are a few 100uF 250V caps in the switching supply that can go pop. I think in some cases if the PSU isn't turned off quickly when the caps fail then the PSU then gets confused and it can damage itself further in its attempts to provide the correct regulation.

It happened to mine but luckily I was sat next to it when it happened so I turned it off straight away. It seems to be a common failure mode.

[Dickie]

I'd vote for changing the PSU caps as well. They lead a hard, hot life in that PSU and you want to avoid any failures if you can. Being a bought-in part there are no drop-in replacements available, no servicing information or schematics, and running around changing rectifier diodes and switching devices is no fun.
Glad it's working OK.

[G0HZU_JMR]

One minor niggle is that this sig gen isn't as easy to drive as others when setting up AM modulation.

From a power up I think it requires a lot of button bashing.

eg
[CARR FREQ] 693 [kHz]
[RF LEVEL] 20 [uV] (you can also pre-configure the sig gen to either volts PD or volts EMF elsewhere in the menus but this may require the password)
[MENU]
[NEXT] (such that modulation gets highlighted)
[SELECT] (use PREV or NEXT buttons such that modulation mode normal is highlighted)
[SELECT] (use PREV or NEXT buttons such that AM INT modulation is highlighted)
[MOD] 30 [%]
[MOD ON/OFF] to ON. This on/off toggle button is hiding over near the RF output N connector
[SOURCE ON/OFF] to ON. This on/off toggle button for the modulation source is also hiding over near the RF output N connector
[CARR ON/OFF] to ON.

That should do it for 30% AM with 1kHz internal modulation with a sinewave. It is possible to save this in memory to allow faster recall. It can otherwise be a pain if you want to swap between AM and FM fairly frequently.

[Wendymott]

Hi Jeremy... Thats great.. many thanks.... I found AM Mod but it is / was off... I have placed the 2023 on the shelf, ready for a RF out coax lead to the bench. AS you say... its not an easy thing to drive... Not like my Anritsu. Ok about the 100 uf x 250V caps... Now I am keeping it.. I can open it up....

[G0HZU_JMR]

One thing to note about the PSU is that I think some of the inner metalwork of the PSU is live with high voltage. Normally this is covered up with a metal cover but if you take this off to inspect the PSU then be aware that the heatsink and some other metal parts may actually be live rather than at chassis potential. I've never powered mine up with the PSU cover off. I don't like messing with stuff like this when it is powered. In my case, it was obvious which cap had failed as the top had popped open and it had burped out some brown oily stuff against the underside of the cover. See the image below.

I replaced all of the 100uF caps in the PSU after this happened. You can see the one on the left had failed. This capacitor also has a large red warning sticker on it to warn of the live metal parts in the PSU. I'm not sure but this might include the metal heatsink.

[joebog1]

I am always amazed at how well members here respond to questions. A very good show chaps, indeed.
I am glad wendymott "fixed " the problems, has a manual, and advice on common failures.

Joe

[G0HZU_JMR]

You've probably found this already with google but Dave Jones did a teardown of a Marconi 2023 several years ago. It is quite well made inside.

https://www.youtube.com/watch?v=Gmryy5KWm_g

One other thing to be wary of is that the little square side handles at the front corners of the instrument can be quite brittle. Don't be tempted to pick up the sig gen using these, especially using just one of them. At work I've seen several of our 2023/4 sig gens after they have been dropped because these brittle plastic handles can fail and snap off with age.

They are a weak point. Normally what happens is the LCD display fails or it develops lost sections within the display if the sig gen gets dropped on the floor.

The front panel buttons can also become deaf or intermittent with age/use which can be annoying. I'm not sure what the fix is for this. It might be as simple as cleaning something but the best place to ask about this stuff is the Marconi Groups website. You may have to be a bit patient with respect to getting a reply on there though.