Mr Pudding

I keep waiting for something to go horribly wrong.

Following on from yesterday’s success, I was able to confirm today that the reed switches are all behaving properly. This means that both stop jambs are now functional. I still have to program the BBS-1K modules that they plug into, but that’s a trivial detail (he said, sealing his fate). Today’s activity centred around unscrewing the manuals. I didn’t think I’d have to do that again, but there you go.

When I first wired up the manuals, I connected the 0V wire of the LED to the common ground of the thumb pistons. Now I come to actually wire them up, I realise that this is incorrect. The LEDs will be driven by another MIDECO module, via a MIBO-LITE board. This requires the 12V connection to be “always on”, and the 0V connection is made or broken by the MIBO-LITE. This necessitated a quick soldering job on the underside of each keyboard, to break the connection to the common ground and attach a long lead for connection to the module. What larks!

While the keyboards were disconnected, I took the opportunity to screw down the boards which will turn LEDs on and off. Apart from the three on the manuals, there will be another 32 behind the rocker tabs. “Rocker tabs, you say?” (I hear you cry.) More about them at a later date.

David has promised to return the toe pistons Real Soon Now™ and then I should be in a position to make the organ playable again. I miss it.

Early testing suggests that the reed switches are all behaving. More substantial testing tomorrow.

Everything on the left-hand stop jamb is wired up, at least in theory. I have connected the solenoids to the MIDECO modules and tested them. After a bit of reprogramming of all four modules (two for each jamb), I now have programmatic control of every drawstop. After exercising all the stops, I have noticed that 18 of them are a bit sticky. This is caused by cracking of the moulded plastic sleeve around the shank of the drawstop. The trick is to unscrew the shank, shave the sleeve slightly to account for the expansion diameter caused by the cracking, and re-insert. I’ll do that at some point over the weekend, when the conservatory isn’t quite so oppressively hot. Still, at least it isn’t as bad as last week.

Once I have the drawstops all moving nicely again, I must return to the painful subject of the reed switches. Getting the switches on the right-hand jamb working properly was an exercise in pain. I fervently hope that the lessons learned from that experience will make the left-hand jamb easier. If not, I may have to resort to gin and tantrums. I may resort to gin and tantrums anyway.

I have made a start on the left-hand stop jamb. This one has 34 drawstops, and no added extras. Hopefully it won’t take too long to wire everything up, having learned from my previous mistakes, but there will then be a pause until the last order of components arrives from Midi Hardware. Given the ongoing component shortage, this could take until August. Oh well, there are several other things going on at the moment, and I’m not going to be bored.

Finally, after five painful months of soldering, unsoldering, resoldering, replacement pots, replacement wires, replacement reed switches and more, the right-hand jamb is finished. All 35 drawstops send the correct signal when drawn on, and again when put off. Each of the stops can be activated or deactivated by MIDI messages, which are converted into solenoid pulses. There are two 3-way rotary switches, and four pots, all of which send the correct messages when fiddled with. There are no stray messages being sent anywhere. It all works.

I need to shorten and/or tack up a few wires, but the work is essentially complete.

I have already prepped the left-hand jamb, to which I now need to solder 138 wires, but first I need to extend the 12V, 18V and GND lines across to the other side of the console.

Time to order more wire. By the end of the project, I will have used more wire than ITER.

I hate pots. I hate RFI. I hate lifting the jamb in and out of the console like a demented hokey-cokey.

I am pleased to report that the SAMs all work exactly as they are intended to work. Everything is now wired up on the right-hand jamb, and all MIDI messages are generated and received correctly.

There is a little bit of noise from one of the pots, which only appears when both MIDECO boards are wired up. There is no connection between the MIDECO and the POT12 controllers, so RFI must be the culprit again. Moving the POT12 board removes most of the noise, and reducing the bit field of the pot removes the rest. This means that there is one pot with range of 0-31 (compared to 0-63), but that won’t be a problem. David is going to, ahem, ferrite out some ferrite beads to see if they help.

There are two sticky pistons. From the names on the stops (Great Enclosed, and Trompette En Chamade 8), I suspect that they were rarely used in the Lady Chapel of Buckfast Abbey – this may explain it. As per David’s instruction, I’m going to dismantle them both and see what is wrong.

So I get to dismantle the jamb again. Yea, verily, my cup runneth over.