Modulus-86 build thread

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Hi Bill,
Have you tried some anti-seize compound?

You may just have to take the bike apart every couple years to avoid this.

-Chris
Yeah its the 'every couple of years' that is the problem. Right now spare time is precious and the bike only gets attention when something breaks. Poor old thing is 30 years old now, but I like the ride (753 old skool steel).It does need re-painting though. Might be a job before the winter.

Or yearly... I went to college in Copenhagen. 6 km each way in all sorts of weather, including horizontal rain and salty snow. Thankfully, it was a straight and level road (not uphill both ways... :)) I'd totally trash the chain and cables through the winter and just replace sprockets, chain, cables, and a few other sundry items once spring rolled around.
Yeah that's about how mine goes. New chain and rear cogs each sping. The failure that caused the problem was the left crank snapped off. I hadn't seen the crack under the mud but was wondering where the creak was coming from! Either I need to get an electric impact wrench or next set of pedals are spannerable! (oh and luckily no hills at the moment as front mech has seized).
+1 for Lindström Tools. I've been drooling over their RX series of ESD-safe tools for years. Ergonomics matter - especially if you use tools more than just a few times a year.

Tom

Turns out my loved and trashed end cutters are £70 to replace. phooey.

Anyway, back on topic. Tapping heatsinks. Since I realised I can't use the existing holes and need new ones as I realised trying to fill in the machined slots with copper shims was a silly idea and my nearest mate with a mill is a 90 minute drive each way. Any reason why I shouldn't hand tap? I don't have a tower drill just one of those cheapy stands you put a domestic drill in so very uncomfortable about using power assistance.
 
I have bought two of your modulus86 boards plus the power86 board. Mouser wants me to wait until July for some of the components. A couple of resistor values, the 180pf capacitors, the 1N4007-T diodes, the rectifier bridge and the heat sink and the Amphenol 3 Pole terminals.

Please toss me an email with a list of the parts you can't find substitutes for. I'll be happy to help. You can reach me by responding to any of the emails from my website, by filling out the Contact Us form on my website, or by adding @neurochrome.com to my username here.

I'll get you hooked up. Most of the components have substitutes available. The heat sink for the diode bridge will be a bit tougher.

Tom
 
Tapping heatsinks. Since I realised I can't use the existing holes and need new ones as I realised trying to fill in the machined slots with copper shims was a silly idea and my nearest mate with a mill is a 90 minute drive each way. Any reason why I shouldn't hand tap? I don't have a tower drill just one of those cheapy stands you put a domestic drill in so very uncomfortable about using power assistance.

I hand tap all the time. The slowest speed on my drill press is about 500 RPM which is way too fast for tapping. I suppose I could get a tapping head, but that seems rather overkill.

I'd drill the holes using the drill stand to make sure they're square to the heat sink. Then hand tap. Remember to use some kind of cutting fluid. I also recommend using a tapping block. You can make such a tapping block pretty easily by drilling some holes into a block of aluminum (or other metal). The hole needs to be just large enough to fit the tap. The block is used to keep the tap perpendicular to the workpiece.

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


Tom
 
For those wanting more supply capacitance, higher current handling capability, and fancier snubbers...

Tom
 

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McMaster offers two versions:

One for metric threads: P/N: 9550T13
One for SAE threads: P/N: 9550T12

They're a bit pricy and, as I mentioned earlier, you can make your own by drilling a few holes in a block of metal. That said, they do make tapping go a lot easier.

Tapping block + cutting fluid = no broken taps.

Another search term: "Tap Guide". Amazon has a couple of them.

Tom
 
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Hi Tom,
Gee, I went from not knowing they existed to seeing options to buy. Many thanks! I wouldn't have even known to search for them (or where).

It was expensive for metric and SAE, but they are on the way. It was less expensive to go direct to the supplier instead of using Amazon. Shipping was the killer there.

Thank you Tom

-Chris
 
One could do the same with a small piece of wood; no need for it to be metal for casual use.

Probably true, though wood may be a bit messy with the cutting fluid. That said, for casual use a chunk of hardwood is probably fine as long as it's square and likely to stay that way.

Gee, I went from not knowing they existed to seeing options to buy. Many thanks! I wouldn't have even known to search for them (or where).

You're quite welcome.

Tom
 
Chassis received and more or less assembled. Now for the layout/wiring... would anyone see any problems if it would be more or less like in this picture (I know, there are some wirres issing but it's about the run for the cabling now) ? Mainly EMC stuff etc I'm concerned about. Or shouldn't I ?

wiringtcu25.jpg


From power input to transformer can be run high along the side/top or low, underneath the perforated base.

volumepot and selector will be placed on aluminium brackets and shafts extended to the front. Orange thingies are couplers and I will have very small bearing block on the frond plate inner to support the shafts. (good to have a 3d-printer :) )


Any comments would be welcome.

Thanks !
 
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...Any comments would be welcome.

Thanks !

In general looks great to me except maybe the quality of that selector switch, in past myself used one that looks exactly the same and mine wasn't very good quality to let active music signal stream pass through it in the long run, it would be much better to use it for electric steering of some quality relays, hope its a alright comment and taken for good : )
 
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Hi Reddo,
I would move the power supply board closer to the transformer to reduce the length of wire carrying high current pulses.

I agree with BYRTT on your input selector switch. Even the older open ones are better for contact performance in the long run. I used one to control a relay and had to pull it after three years. I went with something more reliable.

-Chris
 
I'm surprised to hear that the Lorlin/C&K switches wear out that quickly. I guess you do get something when you buy those Elma switches. :)

Regarding relay switching: That can be a crapshoot as far as reliability goes as well. Don't skimp on the relays if you go that route.

Overall, the arrangement above looks reasonable. I would mount both MOD86 boards top side up. You aren't gaining anything by flipping the one on the right upside down. Yes, the output cabling gets a little longer, but it's in series with your speaker cable, which presumably is longer than the wiring inside the chassis.
Nice touch with the primary wiring running to the heat sink and then to the mains connector. I was about to suggest that when I noticed the white lines in the drawing.

Tom
 
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Hi Tom,
I'm surprised to hear that the Lorlin/C&K switches wear out that quickly.
Like I said Tom, I avoid that brand of switch these days. They work well for a while, then they get so bad you can't get a reasonable amount of time even after cleaning them. I've even tried to take them apart for cleaning and it didn't help that much.

Avoid.

-Chris