F5X -- the EUVL Approach - The Build Thread

[NicMac]

Where/how is the BAW76 mounted on the Mute PCB?

[EUVL]

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

[Horio]

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?

[EUVL]

This is not a problem I am aware of, and it can be to do with the Gerber files.
Can you give me more detail -- photos, location of mismatch, amount of mismatch, etc. ?

We shall then either suggest a work-around to you, or bear the cost of new capacitor brackets.


Sorry for the inconvenience,
Patrick

[Horio]

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.

[Horio]

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.

[EUVL]

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

[JBdV]

I have the same issue, my PCB's are already soldered

[EUVL]

Those in Europe can send the Delrin blocks to me and I shall mill long slot for you to fix the offset.
Will take a while though, as I want to do them all in one go.

If you feel confident try the countersink trick. It should work fine.
Give Horio a day or two to show his trial results.


Patrick

[EUVL]

I just checked my drawing records and can confirm it is a PCB layout error.
It was meant to be 28mm, so the machining was correct.
My own hand-etched PCBs also have 28mm.


Patrick