Anyone got this old Dutch driverboard fully built? Need help.

[MiXiN]

I've got the PCB & component list to build this old 1W Dutch driverboard that RF Head used to sell, but the component layout, particularly some Resistor values don't match what I'm seeing on some fully built boards.

I've only found a "partial" good quality image posted by Gigahertz on here, and also a blurred image on Google search - and many Resistor values don't match.

Has anybody got a good quality image of a fully built board so that I can compare it with the component layout provided?

Here is the component layout, a blurred image of a fully built board, & and a partial good quality image of a fully built board.

ebay6 (1).JPG

s-l1600.jpg

IMG_1814 (3).JPG

[sinus trouble]

Hello Mixin

I have seen so many variations of this exciter over the years! My advice would be to go with the information that NRG gave you, I believe it is accurate and works.

[MiXiN]

Cheers Sinus.

I guess he'll have sold a good few, so if there was an issue someone would've mentioned something.

I just find it odd that a good few Resistors vary from board to board, but maybe they're not critical type of thing.

I'll knock it together & report back by Monday.

[sinus trouble]

No worries Mixin

It really depends on what resistors are in question? Some could be critical? Some could be just 'Pull Up' data lines?
Anyways! I dont think you will have any problems? Just ask if you need to.

Good Luck

[teckniqs]

Yeah if you got it from NRGUK then the piece of paper diagram you received will be 100% accurate.

....built one of the kits he's got on eBay the other day and it worked perfectly first time.

[MiXiN]

Yeah if you got it from NRGUK then the piece of paper diagram you received will be 100% accurate.

....built one of the kits he's got on eBay the other day and it worked perfectly first time.

Alright Teck,

I never received a paper diagram from him, but I did receive this when I bought it -

s-l1600.jpg

Done some more digging & asking around today, & got this -

IMG_20200422_120100.jpg

Most values are the same between these parts layouts, so I'm not sure which to copy.

All resistors match from layout to layout, but some Capacitors are different this time.

Do you know which one you had mate?

[thewisepranker]

Any good?

[MiXiN]

Completely forgot about this thread as I was going through some problems at this time.

Many thanks @Wisepranker - that matches my board exactly.

Just finished building mine, & it's doing 1.5W level all through the band, but doesn't lock at 108.00 Mhz.

Locks fine from 87.5 > 107.9

What's the purpose of the TOKO variable inductor near the pot? Is there a specific way it should be set?

I remember with the old NRG boards that there was an optimum voltage (3.2V?) that should be set by testing the voltage across a Transistor. Is there any similar optimum way to set these up?

20210511_161519.jpg

[Bton-FM]

@MiXiN

The shielded TOKO inductor is there to set the centre frequency of the VCO and therefore changes the error voltage the PLL chip is sending to varicaps.

The best place to set it is in the middle of the voltage range the PLL can produce so that you have the maximum swing in both directions before the VCO goes out of range from temperature.

[MiXiN]

@MiXiN

The shielded TOKO inductor is there to set the centre frequency of the VCO and therefore changes the error voltage the PLL chip is sending to varicaps.

The best place to set it is in the middle of the voltage range the PLL can produce so that you have the maximum swing in both directions before the VCO goes out of range from temperature.

Cheers for this bud, but where do I check the voltage please? A layman's method is best.

I'm running this at 13.8V rather than 15V for what it's worth, as I'm already seeing 1.5W out of it.

Sorry about the basic questions, but I've only just started building PLL stuff apart from the old NRG gear and it's all new to me.

[teckniqs]

If you twist the ferrite one whole turn anticlockwise (upwards) it will probably tune to 108

[MiXiN]

If you twist the ferrite one whole turn anticlockwise (upwards) it will probably tune to 108

Alright Mr T,

Did this & it locked in at 108.00.

Not fed any audio into it yet as it could really do with a taller TO5 heatsink.

Do you know where to check the voltage for setting the screened TOKO coil mate?

[Bton-FM]

@MiXiN

The shielded TOKO inductor is there to set the centre frequency of the VCO and therefore changes the error voltage the PLL chip is sending to varicaps.

The best place to set it is in the middle of the voltage range the PLL can produce so that you have the maximum swing in both directions before the VCO goes out of range from temperature.

Cheers for this bud, but where do I check the voltage please? A layman's method is best.

I'm running this at 13.8V rather than 15V for what it's worth, as I'm already seeing 1.5W out of it.

Sorry about the basic questions, but I've only just started building PLL stuff apart from the old NRG gear and it's all new to me.

One of these diodes is the tuning diode but I don’t know which. If you measure the voltage on both of them then change the frequency, the one where the voltage changes is the tuning diode. The other is for modulation. Measure at the anode (side with the stripe).

305F3531-40A4-40B0-B61A-A5F46370AB0E.jpeg

EDIT: Don’t worry about it though it’s not critical. As long as it’s not really close to ground or supply it will be fine.

[Bton-FM]

My mistake the stripe is the cathode!

[MiXiN]

Nice one, Bton-FM you're a legend.