Help with Veronica 12w rig....

[radium98]

schematic only for troubleshooting.

[Polecat]

Thanks @radium98. My understanding of what goes on inside this box is close to zero so please bear with me.

I can tune the VCO and make the lock/unlock LED go on and off. What you suggested after that is, I'm afraid, beyond my comprehension. And the diagramme? Errrrr...

I was hoping someone would say I'd missed an important step in the setup. But as that's not the case, I'm going to need someone who knows what they're doing to look at it.

If I don't hear back from Sinus in a week or so, I'll probably send it back to AERFF to repair.

Thanks for your interest anyway. I'll update this thread when it's sorted out.



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[Shedbuilt]

If you're able to make it show "locked", and "out of lock", by tuning the VCO, the symptoms seem slightly strange. How close is your radio, to the driver board ?

[teckniqs]

How close is your radio, to the driver board ?

Exactly what I was wondering

[Polecat]

Thanks both.

The transmitter and antenna were in one room and the radio was in another, about 20 feet away and the other side of two internal walls. That should be okay for testing purposes?

I agree it's all a bit odd. It's like all the lights are on but there's no-one at home. And yes, I'm talking about the rig...

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[Polecat]

Update!

I put an old CB radio SWR meter on the rig to test if anything is coming out of the box and yes, there is something.

A did a bit more testing and now I can define the problem much more specifically - I'm transmitting music on 88.2 but the signal is silent on 105.5.

These may be clues that point to the source of the problem, or maybe not.

Any further thoughts would be much appreciated.

Thanks!

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[shorty]

Put your radio right next to the transmitter as close to the oscillator as you can to see if you get a carrier on your selected frequency, if the output transistors on the driver and amp have blown the signal will be weak, as close the oscillator as possible without touching.

[radium98]

Shorty is right .does the rf led on the pll board lit ?
If yes i suspect to check the voltage on the predriver buffer 2n3553 or c1947 i think the later from the case looking gold.if voltage correct i suspect the transistor buffer is blown.could be wrong .

[Polecat]

You guys are very helpful, thank you.

I tried putting the radio next to the oscillator but the LCD display went crazy and I wasn't sure what frequency I was on. The antenna is in the same room so guess that's causing a problem.

I don't have any testing equipment so I think I've come to a dead end. But at least I have a starting point to pass on to someone who knows what they're doing.

Sinus Trouble said he'd take a look and when he returns to the forum I'm hoping he gets in touch.

I'll update as and when.

Thanks again!




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[radium98]

what is youre problem ?
power or harmonics ,if it is harmonics ,it is hard without spectrum to troubleshoot the filter , or any defected capacitor.
regards

[Polecat]

Yes I get that Radium. I need to find a local engineer. SE London recommendations anyone?

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[teckniqs]

The transmitter and antenna were in one room and the radio was in another, about 20 feet away and the other side of two internal walls. That should be okay for testing purposes?

Too far away.

...I see you since say it was overloaded when close by, if you are using a telescopic receive antenna fold it all the way down and if you have a piece of wire you can remove then take it out, you should still pick it up next to it and it should only be detected on the fundamental frequency.

[Polecat]

Shame but thanks for the thought.

I've put everything away now and will pass all this info on to whoever I find to look at it.

There's clearly some curiosity around this so I will share the outcome when it's sorted.

Appreciate the support.

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[Polecat]

Looks like I left this thread hanging so I came back to let you necks know there was a happy ending

There was nothing wrong with the rig. Seems I went gangbusters on the fine-tuning screw and went way past the point where it had locked. Thing is, the lock light stayed on so I had no idea I'd over-egged it.

It was a dumb thing to do. But for the benefit of anyone else setting up a dip switch-based tx, let me just say one thing: read the fuckin instructions!

When it says turn the fine-tuning screw slowly until the unlocked light starts to flicker it really means turn it SLOWLY. And when it says to stop once the locked indicator lights up, it means STOP AS SOON AS IT LIGHTS UP.

Huge thanks to Sinus Trouble who patiently explained all this to me whilst somehow resisting the urge to take the piss. Thanks on both counts mate!

[Rfdiva]

Happy ending mate .good to listen to that.

[Polecat]

Happy ending mate .good to listen to that.

Yep. Hooked up to the matching compressor-limiter (I managed to set that up properly lol) it sounds sweet.

[sinus trouble]

How Dare you suggest id take the piss Mr Polecat!

Im glad its working as it should, Plus a pleasure to work on such a magnificent piece of engineering history!

[Polecat]

How Dare you suggest id take the piss Mr Polecat!

Im glad its working as it should, Plus a pleasure to work on such a magnificent piece of engineering history!

You're a star Sinus!

[radium98]

for sure Sinus