Replacing the dashboard plastic PCB

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CovKid
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Re: Replacing the dashboard plastic PCB

Post by CovKid »

Pic on this page Chris - fairly sure thats a petrol rev counter as it has three connectors on end of membrane - think diesel has two?

http://www.vanagonauts.com/Warning-Light-Fix241.htm" onclick="window.open(this.href);return false;

I have a feeling this is going to be a cul-de-sac all of its own though. :shock: I had to solder directly to a cut-off piece of membrane to get mine to work. :(
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Re: Replacing the dashboard plastic PCB

Post by CJH »

Thanks Ralph

The relevant pic from that page I think:
Image

Are they pins under that part of the ribbon cable, with a socket fixed to the underside of the ribbon? I wonder if they are at the same ~4mm pitch as the DOPS connector discussed earlier in this thread.

Image

If so, then maybe the same 'Dupont' sockets would work.
Image

The assignment and order of the pins on the petrol and diesel versions would be useful. If those Dupont pins turn out to be suitable it wouldn't be too difficult to add an option for the factory tacho(s) to the next iteration - even the current iteration could be made to work quite easily I think.
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Re: Replacing the dashboard plastic PCB

Post by CovKid »

Have posted that we're in need of pics. I'd have to strip clocks out to get a proper pic & measurements of petrol tacho - next week?
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Re: Replacing the dashboard plastic PCB

Post by CJH »

Thanks, yes I saw that post.

I've been experimenting with the PCB-mounted LED for the symbols illumination, now that there's a spot on the PCB for it. And my spare binnacle has the blue cap in the main beam location, so I thought I'd try a white 3mm LED behind it. As this is my test board for trying various resistors, LED heights etc (it's a bit of a mess now - there's only so many times you can unsolder components) I didn't want to use up my limited stock of LED spacers, so I've mounted these without spacers. The 3mm white LED would need a shorter spacer anyway since it sits behind the blue cap, and the big white LED will need a 3-4mm spacer to ensure that it ends up where the filament bulb would do in the conventional setup.

Image

I've found that this particular white LED needs about a 20k resistor to dim it down enough to not dazzle - less than the blue LED needed, but that's because the blue cap dims it a bit.
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Re: Replacing the dashboard plastic PCB

Post by CJH »

Just right, I reckon. The kit won't come with dust - you'll have to add that yourself.

Image

The new bright white bulb holders have quite an impact on the light colour. So I've also got some 10mm 'warm white' LEDs on their way - I'm hoping they'll give a more retro look, more like the filament bulb illumination in my oil pressure and temperature gauges next to the dash.

Image
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Re: Replacing the dashboard plastic PCB

Post by CovKid »

Illumination is a subjective thing although I found light that includes too much blue became harsh on the eyes after a while at night. Green seemed the least harsh and is the colour I still use now (day or night) but warm white would be the most universally acceptable. As a general rule, bright white is good for illuminating your way (ie work lights and torches) but anything you plan to sit under for extended periods should be warm white or at least further from the blue range of the spectrum. I recently replaced every domestic bulb in my parents house and made a point of using warm white in living areas and bright white for common work surfaces.

The other thing you have to watch out for is stray light from the edges of the dash cover with bright white. In my case I dispensed with the dimmer as I was able to settle on a level of illumination via the resistors and the dimmer space is now occupied by a discreet chicken switch but some still may like the ability to dim dash lights.
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Re: Replacing the dashboard plastic PCB

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I configured the jumpers to use the standard dimmer supply, and I went with 470 ohm resistors to suit 12.7V. The range of brightness of these 10mm LEDs on the dimmer isn't as great as the 12V LEDs I had before (no idea how it compares to the original filament bulbs), but its enough. I suspect that bypassing the dimmer would make them brighter, so a bigger resistor might be needed, although I haven't checked the dimmer voltage on 'full' brightness.

I made a device for locating the LEDs at the correct height above the board. I think this might be better than supplying spacers in the kit, as it allows the LEDs to be held in the right place for soldering, whereas the spacers really require three hands.

Image

Image

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Re: Replacing the dashboard plastic PCB

Post by CJH »

A couple of iterations later and the LED fitting device now helps with all three types of LED (5mm at 16mm height, 3mm at 15mm height, and 10mm at 3.5mm height).

Image

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Re: Replacing the dashboard plastic PCB

Post by CovKid »

Well thought out! :D I think I had to solder mine by trial and error - far from ideal. Agree, spacers not needed if you provide a guide.
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Re: Replacing the dashboard plastic PCB

Post by CJH »

CJH wrote:...and I suspect that what I thought could be a one-size-fits-all solution isn't quite suitable for every variant yet.

I found this diagram in a previous thread on this forum:

Image

Combined with the information on this thread, it looks as though the current PCB can serve the tacho/LCD clock variants as well after all.

The tachometer seems to need just the tacho signal on the multiplug plus an ignition live and GND. The PCB supports a connection for the tacho signal, and there are various options for IGN and GND. It would be straightforward to add an extra wire into the main IGN and GND terminals for instance. And hopefully the pins in the back of the tachometer will work well with the dupont sockets pictured earlier.

The LCD clock seems to need a permanent live and a GND (already specifically provided on the PCB for the analogue clock), plus a dashlights live and earth for the backlight. Assuming the 10mm white LED is used for the central symbols illumination, then the board already has a spare dashlights terminal that can be used for the LCD clock.

So this isn't to say that there won't be a further iteration to put dedicated terminals on the PCB somewhere, but the current version can already support the tachometer and LCD clock.

It would be good to know about the petrol tacho pinouts, and it would also be good to know about the LCD live and earth connections, and the bulb type for the backlight.
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Re: Replacing the dashboard plastic PCB

Post by CJH »

My bulb holders arrived. I love how they get a sealed box printed around them.

Image

...and there isn't room for the parts to move around, so they're still in the positions that I arranged them in in AutoCAD.

Image

They've come out ok. They have the texture of an extra strong mint - slightly powdery look - which will probably help to diffuse the light if anything. The 10mm LEDs fit nice and tight.
Image

Image

A couple of issues:
- The arms came out a fraction fatter than they did on my printer, so they're a bit tight in the binnacle - will adjust them if I do another order
- The binnacle in my van has a slight difference in this area compared to my spare binnacle - there are some wedge-shaped end stops, so the ends of the arms need to be shaped to fit over them - easily done with some sandpaper. If I do another order I'll slice a bit off the arms to match the end stops.

Image
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CJH wrote: One tiny little thing to note. At idle I'm now getting the very faintest glimmer from the battery light, which I don't ever remember seeing before....

I've bought some different LEDs for the warning lights - they're more diffuse, so they look better, but their brightness ratings are different, so I've had to experiment with different resistor values. The first red LEDs that I had were a touch too bright with 470 ohm resistors, and the new ones are even brighter so I went to 3k9 resistors and they're closer to the brightness of the original dash, and more to the point, I no longer get the battery light glimmering at idle. Since the different colours all have different brightness levels, I've had to test different resistors with each colour. I think I now have a setup that works well. The photo doesn't capture the colours very well, but it does show that the blue LED is dimmed down quite a bit, deliberately, since it's mostly used at night.

Image

So now I think I have a finished kit ready to go. Just need to tot up the cost of the parts so that I can set a price, and finish the documentation.

Standard kit:
Image

The bulb holders came out a bit more expensive than I'd hoped, after adding VAT and shipping, so I'll make them an optional extra. With optional bulb holders and 10mm LEDs:
Image

Here's the standard set of LEDs - three options for the high beam:
Image

and here's the selection of resistors that I think will work well:
Image
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Re: Replacing the dashboard plastic PCB

Post by CovKid »

I'm really impressed at the speed you've moved on this. It had always been my intention to make up a multi-use board but as the hardwire worked, I suppose I shoved it on the back burner Chris. That said, its much harder to trace a fault compared to a custom board. Interesting that you were getting a dimly lit ignition light. Mine suffers from that so no doubt down to the LED/resistor combination.

Much of my time since has been spent on setting up a self-contained power system in my camper without the need for hookup - ever. I still love the chains of LED lights you get in pound shops as they're cheap, and the draw is so low. They're impossible to beat. Bought in a load of 12v>3v droppers and love the lighting at night. At one time I had the LED strip stuff but you soon get cheesed off with the disco effect and the draw is way too much to be a viable lighting system long term. I once flattened a leisure battery on those strip ones, so in the bin they went!

Once I'm through this years MOT, I want to finish my engine bay fire detector (it stops the fuel pump and gives an alarm if it sees a flame). Seems to test out great on the bench but needs road testing to some extent. Fitting a fire extinguisher in the engine bay is a good thing, but I'd rather stop the potential of a big fire way before it gets to that stage. :shock:
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Re: Replacing the dashboard plastic PCB

Post by CJH »

I've done my sums, and I reckon I can sell the full kit, excluding the replacement bulb holders and bulbs, for £27.50 (plus postage). At that price I should cover my costs and have a bit left over for a beer. It's not quite as cheap as I'd originally envisaged, and that's mostly down to the extra costs of the oversize board (one dimension went over 100mm), the gold finish on the adapter board, and the duty that becomes payable once the order value goes over a certain threshold - it's a vicious cycle! But it's still not a bad price I think, given that it contains all the parts needed, including a bespoke 3D-printed LED soldering gauge and a bespoke 3D-printed terminal insulating clip.

Image

I can add a pair of replacement bulb holders, plus the 10mm LEDs and wiring to suit, for an extra £12.50. Again, more expensive than I'd hoped, because the bulb holders take up quite a lot of space in the 3D printer, but if you don't want to permanently alter your original bulb holders they give an option. I have a few pairs available that will suit binnacles that don't have the wedge-shaped end stops (see earlier post), and if there's any interest I'll have some more made that will suit both binnacle types. So everything in this photo would come to £40 (plus postage).

Image

Untested at the moment with clusters that have the tacho and/or DOPS options, but I'm reasonably confident that the Dupont connectors will suit the pins in those two connections. And I haven't been able to check how to connect up to the LCD clock (more Dupont pins I think) and the LCD clock backlight (another bayonet-type bulb I suspect), so it might be worth steering clear until those details are sorted out if you have that type of dash.
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Re: Replacing the dashboard plastic PCB

Post by garyd »

Hi,
I have been following this thread for some time since, like many people, my binnacle foil is less than perfect. Like Covkid, I have been impressed with the speed and openness with which you have developed and shared the process.

I have a 1990 ex-TD syncro with the tacho and digital clock style binnacle. Is there anything I can help with regarding the final uncertainties you mention?
Garyd

1990 Transporter syncro camper
2 litre AGG 'GTi' engine

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Re: Replacing the dashboard plastic PCB

Post by CJH »

Thanks Gary - PM sent.
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