New AM/FM RF signal Generator

[specmaster]

I have just acquired what appears to be a top end product back in its day, it was priced at £750 in 1982 but as always, there is problem with these old pieces of kit. The first 6 bands, all of them in the AM range are dead, displaying 0000 on the screen where the frequency should be. I have tested it with an external frequency counter and also an oscilloscope and when the LED frequency readout fails, the output also fails.

The generator is a Sharetree Type 450 and the FM appears to be working just fine apart from a maybe a clean up and slight adjust. The AM however has a mind all of its own and will sometimes spring into life. All switches etc have been cleaned and there does not appear to any lose connections to any of the controls.  So I'm looking for any information on this at all, user manual and a service manual is also required please.

I have searched all on-line sources that I know of and drew a blank also has anyone got any experience of this signal generator at all?

[Terry]

Welcome to our forum - I'm sure you'll make lots of new friends here. 
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I can't help you with your problem, I'm afraid, but I'm fascinated by your user name.

Are you a master of specifications
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or does it relate to things you perch on your nose?     (You may have to click on this to see it properly)

[specmaster]

Thank you for the welcome, my username is a hangover from the time I was employed as a Specification Engineer by a major well known manufacturer of electrical wiring accessories. I had to use my engineering skills to help getting consulting engineers and local authorities etc. to design their projects around the companies products and name them in the specification that contractors had to tender against.

Its force of habit I expect, maybe I might think up a new user name, who knows?

[ppppenguin]

Welcome to GVR.

I see you've asked about this generator here: https://www.eevblog.com/forum/testgear/b...of-before/ and not much has turned up. I'd certainly not heard of Sharetree before.

[specmaster]

How do I add some photos of this please? It might interest some and jog memories of others?

[ppppenguin]

To add a photo or other file click "Reply to this topic" Scroll down until you see the Attachments section. Click "Browse" and select the file you wish to attach. Then click "add attachment".

You won't see the attachments section in the Quick reply box. If you've started on a quick reply and want to add a file or do fancy formatting etc then click "Preview Post" and it will switch to the full editor.

It's possible that attachments are disabled for new users. If so, I'm sure a moderator will spot this post and allow you to make attachments.

[specmaster]

As mentioned earlier, here are some photos of this unit. All the cables are numbered in the same fashion as motor control panels are normally numbered with slip on numbers. The pcb looks like it was made by hand and all the cables are run in looms. I have been round all the joints on the PCB with a iron looking for dry joints with no joy, all switches and pots have been doused with switch cleaner and still no sign of the AM side coming back to life any time soon. Unfortunately I don't know enough about these to be able to track the circuit through without a schematic so the hunt continues.

As Danesbury were the sole distributor for these and they appear to have gone out of business but I have discovered that it would appear that there is or was a function generator made by a company called Danesbury as a calibration house lists them as one of the ones that they can calibrate and repair. Could it be the same company I wonder? I'll have to dig a little more I think.

The last four bands are working and although the display would have you believe that they cover 10 to 180Mhz they actually cover 7.66 to 182.22Mhz as each band has a nice overlap.