BeebMaster Econet Clock Issue 2

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BeebMaster
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BeebMaster Econet Clock Issue 2

Post by BeebMaster »

Continued from here.

BMEconetClock2021-3.jpg
BMEconetClock2021-4.jpg
Took me about an hour to do the first (and currently only) one:
BMEconetClock2021-5.jpg
I didn't cut the legs on the LED in case it needs re-positioning to fit through the eventual hole in the box:
BMEconetClock2021-6.jpg
Probably a good job as I think I have put it on the wrong way wround (long lead to square pad) so when I powered it up nothing happened.

But then:
BMEconetClock2021-9.png
BMEconetClock2021-10.png
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

Very good! I am in Somerset this weekend but when I get home I will have a go at making a prototype case for that.
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Re: BeebMaster Econet Clock Issue 2

Post by IanS »

BeebMaster wrote:
Fri Jun 11, 2021 11:32 pm
Probably a good job as I think I have put it on the wrong way wround (long lead to square pad) so when I powered it up nothing happened.
You didn't fit a switch for the PwrLED, put a wire link across the pins below the "mark" switch.

edit: or has it got JP1 linked on the back?
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

Nice one, BeebMaster. Did the capacitors fit OK, or did any clash with the ICs? Some look quite close.
IanS wrote:
Fri Jun 11, 2021 11:53 pm
BeebMaster wrote:
Fri Jun 11, 2021 11:32 pm
Probably a good job as I think I have put it on the wrong way wround (long lead to square pad) so when I powered it up nothing happened.
You didn't fit a switch for the PwrLED, put a wire link across the pins below the "mark" switch.

edit: or has it got JP1 linked on the back?
JP1 should be linked by default, so no need to put in a wire link. JP1 should be cut if you want to control the LED with the DIP switch.

I'd be disappointed if I got the polarity the wrong way round. I spent a bit of time trying to get the anode and cathode the right way round - particularly with the edge mounted LED, where it was meant to accept a pre fabricated 90 deg LED with holder.
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

Do I pass my soldering exams now?

Tried another LED, the short lead goes to the square pad on the board and then it works. Is that how it's supposed to be?
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

The pitch for everything was correct. The trickiest part was the voltage regulator and having to bend the pins to fit the triangular holes for them, I think that will take a bit of practice. Also the two ceramic caps. Although they were the correct lead spacing, they ones I've got have kinks near the component end of the leads so they need a little bit of work to fit them.

My solder station seems to have gone on the blink as well. Part way through I noticed the temperature dropping, but it seems the control dial is slipping so I might have to look at that.
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

And then there was light...
BMEconetClock2021-11.jpg
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

BeebMaster wrote:
Sat Jun 12, 2021 10:13 am
Tried another LED, the short lead goes to the square pad on the board and then it works. Is that how it's supposed to be?
The square pad on the LED footprint (pad 1) is the cathode (-ve, short lead) and the circular pad (pad 2) is the anode (+ve, long lead). So, yes. That's how it's supposed to be. The flat edge at the base of the LED should be towards the south of the board. It's perhaps not particularly obvious, but this is also shown on the silkscreen.
BeebMaster wrote:
Sat Jun 12, 2021 1:11 pm
And then there was light...
Looking good, Ian. Is that one of the PSUs we spec'd up earlier, and does it fit the socket snuggly? And with that PSU, does the voltage regulator run hot, or is it fairly cool?
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

Currently it's running off the original prototype PSU, which is 10.5VAC 200mA. I haven't ordered the PSUs (12VDC) yet. The heatsink is warm, not noticeably hot, but what is getting pretty hot is the 75159. It's one from my general stock, although only arrived a few weeks back, said to be "new old stock" but I don't think they are. 24 of the 25 I bought worked when tested in Station 128, but I decided they weren't good enough to risk in Econet kits or clocks.

So brand new ones are on the way from TI from Singapore.

I will try an existing Clock though for a few hours and see how hot the 75159 gets.

I made the second board today, took about 45 minutes, but I already had the parts measured out from yesterday. I assembled it in a better order, roughly going from "shallowest" to "deepest" components which makes the job a lot easier. Yesterday I put the crystal on far too early which made it more difficult to keep the IC sockets and other components in place when soldering.
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Re: BeebMaster Econet Clock Issue 2

Post by gslug »

BeebMaster wrote:
Sat Jun 12, 2021 12:09 pm
The pitch for everything was correct. The trickiest part was the voltage regulator and having to bend the pins to fit the triangular holes for them, I think that will take a bit of practice.
Do you have a 3D printer? If not I can print you a lead bending jig. PM me the footprint dimensions and your address and I'll do it ASAP.
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

L7805 footprint dimensions
L7805 footprint dimensions
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

Thank you. I'm not sure it will be worth the trouble. With the second one I bent all three pins at a right-angle where they start to taper, and then bent the middle pin back out a bit probably to 135 degrees to fit the middle hole which is further away. Seemed to work out OK.

I just noticed I haven't clipped the pins on the 7805s but I don't think it will do any harm, when the mounting pillars are added.
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

BeebMaster wrote:
Sun Jun 13, 2021 10:53 am
Thank you. I'm not sure it will be worth the trouble. With the second one I bent all three pins at a right-angle where they start to taper, and then bent the middle pin back out a bit probably to 135 degrees to fit the middle hole which is further away. Seemed to work out OK.

I just noticed I haven't clipped the pins on the 7805s but I don't think it will do any harm, when the mounting pillars are added.
I think the trick would be to bend the outer two legs at the taper (according to the dimensions on the datasheet, the bend might actually need to be about 1mm after the taper) as you've already done, and then place the 7805 (without the heatsink) on the PCB, which should then let you see where the bend in the middle leg needs to go.
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Re: BeebMaster Econet Clock Issue 2

Post by gslug »

BeebMaster wrote:
Sun Jun 13, 2021 10:53 am
Thank you. I'm not sure it will be worth the trouble. With the second one I bent all three pins at a right-angle where they start to taper, and then bent the middle pin back out a bit probably to 135 degrees to fit the middle hole which is further away. Seemed to work out OK.
I've got to go to work now, but can do the design when I get home. Should only take 10 minutes or so.
KenLowe wrote:
Sun Jun 13, 2021 11:42 am
I think the trick would be to bend the outer two legs at the taper (according to the dimensions on the datasheet, the bend might actually need to be about 1mm after the taper) as you've already done, and then place the 7805 (without the heatsink) on the PCB, which should then let you see where the bend in the middle leg needs to go.
That's far too logical for me! Why take the easy option when you can make something?
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Re: BeebMaster Econet Clock Issue 2

Post by 1024MAK »

"shallowest" to "deepest" is almost always the order I do it as well :D

Good work Ken and Ian :D =D>

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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

I'm using a silicon soldering mat - although it's not as non-slip as it claims. If using a clamp to hold things together I suppose it could be done in any order. I've got it off to a pretty fine art now, I did 4 today in all. I measured out all the components first (although a diode disappeared between the 3rd and 4th ones!) which took about 15 minutes, then after that it was about 35 mins per board with long breaks in between.
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

Very good. I'm back from Cheddar Gorge, only slightly sunburned, and I now have a blank Verobox. Depending on how my Monday pans out I would hope to be able to do a bit of punchin' and drillin'.
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Re: BeebMaster Econet Clock Issue 2

Post by gslug »

BeebMaster wrote:
Sun Jun 13, 2021 10:14 pm
I'm using a silicon soldering mat - although it's not as non-slip as it claims. If using a clamp to hold things together I suppose it could be done in any order. I've got it off to a pretty fine art now, I did 4 today in all. I measured out all the components first (although a diode disappeared between the 3rd and 4th ones!) which took about 15 minutes, then after that it was about 35 mins per board with long breaks in between.
Sounds like you are fine without a jig! I'll make a few anyway in case anyone wants one, and I'm sure I've come across a few other PCB layouts using that footprint.
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

It looks like the last info I had from Ian on the desired punching was:

One short side - two round holes of approx 17.5mm diameter with the centre at 16.35mm above the internal bottom of the case and each hole with the centre 13mm from the centre line of the short side of the box.

Other short side - two round holes 12.9mm from the internal bottom of the case, first hole diameter 7mm, second hold diameter 3mm, exact horizontal location to be confirmed.

Ken, can you confirm what the horizontal location of the power LED ought to be?
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

philb wrote:
Mon Jun 14, 2021 11:00 am
One short side - two round holes of approx 17.5mm diameter with the centre at 16.35mm above the internal bottom of the case and each hole with the centre 13mm from the centre line of the short side of the box.
That sounds right.
philb wrote:
Mon Jun 14, 2021 11:00 am
Other short side - two round holes 12.9mm from the internal bottom of the case, first hole diameter 7mm, second hold diameter 3mm, exact horizontal location to be confirmed.
That also sound right based on the info I originally provided to Beebmaster. However, I believe the barrel jack we eventually landed on is different to the one used to calculate the 12.9mm height. Let me check into that a bit further. Edit: confirming that the 12.9mm height is correct for the newer barrel jack.
philb wrote:
Mon Jun 14, 2021 11:00 am
Ken, can you confirm what the horizontal location of the power LED ought to be?
Please see dimensional drawing below...
Dimensional drawing
Dimensional drawing
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

Great, thanks.
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Re: BeebMaster Econet Clock Issue 2

Post by arg »

As a further note on hole-drilling in veroboxes, I found I had in my toolbox a 16mm end-mill (bought originally to make holes for Econet sockets in standard electrical faceplates).

This would be great if I had a milling machine, but I don't; however I thought it worth giving it a spin in a pillar drill at relatively low speed.

It did manage to cut clean holes in the ABS (I was drilling the lids of the smaller size verobox), but only with the workpiece really well clamped down - I completely messed up a lid with my first two attempts, casually held with a clamp, then really well clamped down with two clamps, then finally success with the box lid screwed via its mounting holes to a block of wood and that clamped to the table of the drill. The milling tool is very sharp and tends to 'dig in' to the ABS and then eject the workpiece from the machine!

I was still pondering whether to build jigs to use the end-mill accurately (positioning it by eye is also tricky), or give up on it and revert to my original plan of using the cone-cut, when I ran out of time.

Happy to lend you the tool if you want it.
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

I may be away off the mark here, but could we not just use a 17mm hole saw with arbor, something like this:

https://www.screwfix.com/p/starrett-fch ... 17mm/827hy
https://www.screwfix.com/p/starrett-hex ... 75mm/129hy

To get a straight clean cut in the ABS, I've seen piece of pre drilled wood be used as a guide, having already drilled a pilot hole in the ABS.
Last edited by KenLowe on Tue Jun 15, 2021 9:47 am, edited 1 time in total.
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

KenLowe wrote:
Mon Jun 14, 2021 9:46 pm
I may be away off the mark here, but could we not just use a 17mm hole saw with arbor, something like this:
Whenever I've tried those in ABS they've made a terrible mess of the cut and you end up with quite a lot of burring on the edges which is very difficult to remove neatly without damaging the surface finish. It's possible that I haven't quite ever managed to find the right speed to run them at though, I guess I could experiment. I imagine I have some scraps of ABS lying around that I could use to practise on.

I have a 16.5mm punch which I'm going to try to begin with. If that doesn't work out well for any reason then I might take Andrew up on his offer of the end-mill.
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Re: BeebMaster Econet Clock Issue 2

Post by arg »

I've had similar experience. I think the key point is that you need to slice it rather than abrade it - so the sharp edge of a punch slices through it, or the cutting edge of the cone-cut or milling tool cuts off long slices, while the saw (and other similar tools) is trying to create sawdust and this doesn't work with plastics - it ends up tearing off lots of small pieces and leaving little tails where the material stretched into failure, where a harder material will break away.

Certainly the original SJ products we are trying to reproduce were punched (and I recall at one point we had to tell the subcontractor to buy a new punch tool as the tool was getting worn and the quality falling off).
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

I've made 6 so far, and tested the first 4 with no problems. I will try to have a blitz this weekend and do another 10.

I'm annoyed with CPC, they have made me break my New Year's Resolution not to complain about anything any more, but they did send me a Survey this morning, and for the first time in my life, I participated. Gave them 0 out of 10 for everything and suggested what they could do to improve:
Disgusted of BM Towers wrote:Sending the right items
Packaging the items correctly so that the box did not get damaged in transit allowing items to become lost
Responding to e-mails quicker than 7 days
Sorting out all the problems instead of making me wait weeks for a collection which has still not happened, and then when it does, forcing me to re-order parts and pay for them again even though it was entirely CPC's fault that the wrong parts were dispatched
Overall it feels like CPC believe the customer is always wrong and is made to clear up CPC's mess at the customer's own effort and inconvenience.
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

BeebMaster wrote:
Sat Jun 19, 2021 12:14 pm
I've made 6 so far, and tested the first 4 with no problems. I will try to have a blitz this weekend and do another 10.
Good work. I'm back at home now and I'm going to try to punch a first case sample for you this weekend.
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Re: BeebMaster Econet Clock Issue 2

Post by BeebMaster »

37 of the 50 Veroboxes arrived today, I am yet to check them.

Also all 50 of the 12VDC PSU arrived, first one up looks good, jack fits the socket and the Clock works. New (well, 2015 stock even though just bought direct) Texas 75159 is still getting pretty warm, much warmer than the heatsink/voltage regulator. It gets up to temperature after a few minutes but then seems to stay at that temperature for as long as the Clock is powered on (a couple of hours so far).

Could do with taking a temperature reading of the 75159, but I think the only temperature taking equipment I can lay my hands on is a daffodil...
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Re: BeebMaster Econet Clock Issue 2

Post by KenLowe »

BeebMaster wrote:
Tue Jun 22, 2021 2:54 pm
37 of the 50 Veroboxes arrived today, I am yet to check them.

Also all 50 of the 12VDC PSU arrived, first one up looks good, jack fits the socket and the Clock works. New (well, 2015 stock even though just bought direct) Texas 75159 is still getting pretty warm, much warmer than the heatsink/voltage regulator. It gets up to temperature after a few minutes but then seems to stay at that temperature for as long as the Clock is powered on (a couple of hours so far).

Could do with taking a temperature reading of the 75159, but I think the only temperature taking equipment I can lay my hands on is a daffodil...
Does the 75159 run hotter in these new boards than in your original clock?

Also, will we need cut a slightly bigger hole in the case to take into account the plastic overmould on the PSU plug, or does the outer diameter of the jack extend out far enough so that the plug overmould will not interfere with the case? The datasheets suggest that there is enough length in the plug to avoid having to drill out a bigger hole, but it's worth checking. Perhaps you could post up a photo showing the PSU plugged into the socket?
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Re: BeebMaster Econet Clock Issue 2

Post by philb »

Apologies for the lack of progress with the case punching so far. I realised that I needed my pillar drill to make a decent job of the holes but I had forgotten it was in pieces. And when I went to put it back together I was struck by the bad condition that the base was in, having been neglected in the cellar for a while:
IMG_20210620_120825.jpg
Now looking a bit better so I'm going to put the drill back together this weekend and then I should be in business:
IMG_20210625_183621.jpg
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