F5X -- the EUVL Approach - The Build Thread

Yes, R9 should be 47R gate stopper.
R4 should be 390R for current limiting circuit.

The BAW76 is a clamping diode across the relay coil.
The cathode is connected to positive side of the relay, anode to negative.
When the relay is switched off its inductance creates a reversed voltage spike which is clamped to 0.6V by the diode.

Dave will update when he has a few minutes to breath.


Patrick
 
I was doing a little work on the F5X over the weekend, and I noticed the VE Filter boards not quite align with the teflon support brackets. I soldered up one of the VE filters and noticed that the holes for the terminal blocks pins do not align very well. This prevents the board from sitting flush on the teflon block. Not a major issue, as it can be fixed with a small spacer.

Anyone else run into this issue?
 
It looks like the holes for the pins of the terminal blocks are a bit too far apart. Measuring the +VE Filter board, the distance between the center of pin #1 of J10 and pin #4 of J11 is 25mm. Measuring the distance between center of holes in teflon block, I am getting 28mm. So it appears that each group of holes in the teflon blocks are 1.5mm too far out from center.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
The easiest solution might be a 3mm tall spacer at each one of the 3 mounting holes, and slightly longer mounting screws. Seems like that would be less costly and time consuming than fabricating new brackets. The mounting holes are properly aligned.
 
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Could be misreading 28 as 25 in the layout.
But too long now for me to remember where it came from.
Anyway, mistake is mistake. No excuses.

Do you have a countersinking tool ?
If so, try countersinking each hole of the Delrin block by 1.5mm deep.
The countersink will overlap but that does not matter at all. It is just for clearance.
That should allow the PCB to seat properly even after soldering.

Please give it a try.
If you ruin your block and it does not work we'll replace it at our cost.

The other solution is new cap boards.
Our mistake, so we'll fix it one way or another.
But countersinking is a easy and practical solution. So please try that first.


Our apologies,
Patrick
 
I don't have a countersink tool, but I can use a slightly larger drill bit to chamfer the hole. I'll try it tonight and see how it works. The hole locations are only slightly off, so it should only require a little modification to get the boards to fit. Like you said, the holes will be completely concealed by the boards anyway.
 
Greg, get yourself a countersink tool.
They are not expensive, and will do a much better job than a larger drill size.


Batch 2 PCBs

We have no real need to order them now, as the matching will be done by April.
But they will be done by us, as opposed to your which are a GB made in the USA.
So they will not look the same in appearance (e.g. blue solder mask as opposed to black ?).
If you want perfection then you need to have a completely new set.
Faster we can arrange those would be say some time January.


Patrick
 
I tried the larger drill bit technique, and as you predicted it didn't do a very good job. Like you said, a countersink tool would do a much better job. Trying out the drill bit did make me realize that the required countersink is going need to be very large. A very large countersink is going to be required to provide a cavity deep enough and far enough out to allow for the pints to fit. In fact the outside edge of the countersink may reach the edge of the teflon bracket. I'm starting to think that the best solution is to either mill a single long slot for the pins, or use a spacer to raise the boards off the teflon block by a few millimeters.

I can still try the countersink method with the proper tool, but I won't have the time to pick up the tool until this weekend.
 
Long slot 3mm deep from both ends or through is probably the best solution, but requires a milling machine.
As said, those in Europe can send to me. The rest would have to send t Mark. Or Greg has access ?
Needle files or dremel is another. Not as perfect but fully functional.
Forget the countersunk for now.

New PCB is the easiest, but also most expensive. Also Jan already soldered, so no option for him.
Since the PCBs are from a GB I can only accept partial responsibility (that I did not spot the mistake in the Gerber).
But spotting the difference between 25mm & 28mm by naked eye is a bit beyond the average visual capability.
So we'll have to charge say 50% cost (cap boards only) plus postage if you want new PCBs, unfortunately.

:(


Patrick
 
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