Dx Precision, finally released... now debugged and better than HRII

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Being local South African I already receaved my 2 sets PCB's from Nordic. Cool blue boards with solder mask and component numbers. Holes drilled perfect for different size component legs and board measures roughly 105mm by 202mm. Component outlays done. I would attach a photo but that would spoil the syrprise! The photo doesn't show the quality.

Chris
 
Yes Jetro.... you are a new forum friend and a little bit lost in this place

In this thread some friends will read your message, but opening a thread asking for your manual and schematic, you gonna have much more readers to help you.

No problems...welcome to our group too.... i am just saying that here, in this thread, you will have less chance to obtain the help you need, because only a small part of forum folks come here to read.

regards,

Carlos
 
and another

IMG_0651.jpg
 
Ahhh,

Sweet sweet polystyrenes, perfect cap in this place Nico and just as good as Silvermica, only minus is its easier too screw up with a solder iron due to its fragile dielectric, audiowise near ideal with onlydouble the dielectric absorbtion of air, unfortunately going the way of the dodo and only available NOS,:). How is the P1 sounding Nordic?, I trust well?.


All the best
Colin
 
Yep they are real NOS.... bought them when I was still a teenager...thousands of moons ago....

Got a bit lazy last night... still have to drill the angle stock to attach to the heatsink...so I don't know yet...

The only thing I did not like about the boards is that it seemed I chose too small drills for the pads of some of the wire links...luckily those pads are large enough to drill out a little... and most of them only carries small currents or over short distances so even thin wire should work fine.

Appart from that, it is one of the easier assembly jobs I did... and I am quite happy with how it came out.
 
Hi Carlos,

Some comments on that SMPS (switchmode power supply).
First, 78XX regulators always need 100nF disc ceramic capacitor between input and ground. Then 1uF...100uF (I prefer 10uF) electrolityc (tantalum is better) is needed between the regulators output and ground.
Same for the PWM-IC (pulse width modulator IC): between supply (pin 13, 15) and ground bypass capacitor is needed. I found that 1uF-50V polyester capacitor is the best here. Without these capacitors the regulator circuit would oscillating.
Supply bypassing is very, I say very important in switch-mode power supplies!
Anyway nice simple circuit, I like it. On the margin I'd choose some better MOS-FET driving circuit, and some overcurrent/short-circuit sensing circuit would be a good idea. Don't forget to use a serial mains fuse!
Maybe you will need some snubber circuit over the transformer, it clears up after posting some o'scope measurement pictures.
 
Hi Max,


When buying in small quantities about 40-60 cents for a 100pf SM is normal price, have a look at Ebay for some multivalue grab bags of Silver Micas, values from 2-600pf, ten of each will run you about 20 bucks for 200 caps @100v rating which which will be perfect for most any project, im still digging into the bag i bought over a year ago!..


Best Wishes
Colin
 
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