Happy Halloween!

 

Paradigm Atom v2 Speaker Repair

I have owned various speakers over many year, and I guess I still have most of them.

These Paradigm Atom v2 "bookshelf" speakers I once used used in a kitchen. I think Bill Clinton was President when I got these... Good speakers! These sounded great for their compact size. But they sat idle for a few years, after I moved. More recently I started using them in my workshop.

They seemed to be working fine. A year or two went by, then one of them started sounding pretty bad, particularly on the bass end. Turns out I had the dreaded old-foam problem that seems, eventually, to claim all speakers. Needing speakers though, I decided to research fixing the issue.

Pretty much all stereo style speakers are made the same way. There's a metal frame, a cone made of plastic or paper with the coil attached, and a soft foam surround that supports the cone in the frame. 

At some point this foam surround simply decays and literally turns to dust. Time alone does this. When it happens the cone rubs of the frame, particularly on loud sounds and bass and generally sounds terrible.

What I did not know until I looked into it, is that this is actually pretty easy to fix, by replacing the foam surround.

I bought a repair kit online. I want to say it was like $15? It includes two surrounds (because if one is gone you know the other is about to be), a specialized glue, and instructions. The repair kit is specifically for these speakers with the exact parts used originally. You can get these for almost any speaker, turns out.

Here is the inside of the speaker, back removed and a chunk of padding taken out. I guess on some of these speakers that padding is fiberglass insulation that can be a mess to handle. Mine however was a more conventional foam like you might find stuffing a pillow. It was no problem.

The trouble here is with the larger speaker. It comes right out, unplugging the wires (I took this photo to remember which is which) and removing 4 screws.

Just some gentle pulling on the surround causes it to fall completely to pieces. It's easy to see the problem here...

I removed all the old foam, and cleaned the edges of the plastic cone and the metal frame with isopropyl alcohol to remove any residue of the original glue.

First I glued the cone to the new surround, let that sit, then the new foam to the frame.

There's a couple tricks to getting it all even and the cone centered that I saw both online and in the instructions that came with this stuff. But overall, the job was remarkably simple. The glue gives just the right amount of time to get things in place before it starts getting really sticky.

How did I never know how easy this repair is? This speaker is literally as good as new!

It made me want to go out and find some old high end speakers discarded for having this issue. 

Reassembled, the speaker worked great! But now I can definitely hear the beginnings of that rattle in the other one. No surprise there. I'll do my other speaker too. 

Repairing and Recording an Antique Columbia Grafonola

I have a Columbia Grafonola upright record player originally purchased by my great-grandparents. My whole life it was in the basement of my grandparents' home. It worked fine, and occasionally my Grandfather would play something on it.

Eventually it came to me, including a fair assortment of older style (mechanically made) 78 RPM records. I had the idea that I would like to make digital recording of my great-grandparents' record collection and I figured a good way to do this was to mic up and record this Grafonola itself.

When I got this though, that was a not completely straight forward thing to do. It would take a little figuring out. So the Grafonola sat around for a  few years.

Although it had worked relatively recently, when I did go to play it a few years ago, I found the tone arm was close to too stiff to move easily across the record as they played. I thought it must need some lubrication. But it was not immediately obvious how to remove and disassemble the joints in it. This project not being urgent, I figured I'd come back to it.

More years went by. Oddly, I thought, the problem seemed to get worse. It was a shame because everything else seemed to work.

Overall this unit, built as near as I can tell around 1915, is in remarkable condition. There's barely a scratch on the oak cabinet, the motor works fine, there's no corrosion, and even the green felt pad on the turntable is good.

I figured it really should be possible to get this to work. Recently I became determined to figure it out. So I started with Google and did some reading.

A small amount of background... The player is fully mechanical. There is a regulated spring powered motor inside. It winds up using a crank and turns the turntable, not unlike a clock. Vibration of the stylus in the record's groove is amplified from a mica diaphragm, through the hollow tonearm and a horn-like sound box below. The volume is controlled by opening and closing the baffles on the front.

There are three types of needles used on this player; soft, medium and loud. And yes, that refers to how loud they play. The stylus must be replaced after each play of 2 sides of a record. The used stylus is discarded, otherwise the records will be damaged. New packs of the needles are available today, and are very inexpensive.

These players play records made at 78 RPMs. But they are quite different in other ways from modern LPs as well and not at all compatible. They are even a little different from more modern 78s. There are today a couple makers of photo cartridge and stylus combinations designed to play the old format. I never thought I'd be shopping turntables in 2021, but setting this solution up became my plan B if I couldn't get the Grafonola to work.

It did not take much research to find out that my problem with the tonearm is quite common. The tonearm is made of cast "pot metal". This material, over decades, swells up. Eventually the joints will not move. The only way to fix this is to get it apart, somehow, and sand or otherwise reduce the working surfaces.

I was pleased to learn that, again, this example is in much better shape than most. My up/down joint was fine. The left/right joint was only very stiff. Most tonearms get completely frozen up solid.

Pot metal is very brittle. It is said to literally shatter under too much force. I read about many people having these things crumble in their hands while trying to pull them apart. So I didn't pull very hard... The trick that worked was putting the whole thing in the freezer for a couple hours. After that, the arm came out of its base with no trouble at all! 

A fine sand paper was all that was needed to make the left/right motion work again. I took the extra step though of mirror-polishing the reduced surface because, why not?

   A "dry" (non-paraffin based) lubricant is recommended for the pot metal tonearms. Apparently common oils can make the problem worse. I used a lubricant made for bike chains.

The tonearm worked perfectly. I ordered up some medium needles and the Grafonola is ready to go!

I did a little research on digital recording these days, and found a unit that I had already seem multiple times in other people's write-ups on doing just what I wanted to do with old recording formats. The Zoom H2n is an inexpensive recorder that supports a number of modes and formats. So I ordered one.

I can't say enough good about this little thing. The quality is great. It's the perfect tools for the job.

One thing to note about it though is that it is said to work without a memory card. This is true, but the functionality without memory is very limited. You'll need a card, 2 GB or less (a larger one I already had didn't work).

Now on with the project...

Agora Models Shelby Cobra in 1/8th Scale, Completed!

My 1965 Shelby Cobra, in 1:8 scale, from Agora Models, a COVID project, is finally complete!

This is what's commonly called a subscription kit. Each month, a pack of parts arrive. The resulting model is built up over time. The kit consists of 12 monthly deliveries. But for this one I took advantage of the company's jump start offer of 6 issues all at the beginning, so I completed this car in six  months.

When I started this project, global shipping was at the beginnings of the chaos we still find today. But the shipments none the less arrived. A few ran late, but communication from Agora Models and the status was excellent. Shipments arrived well packaged, complete and in good condition. 

The model itself is a 1965 Shelby Cobra, also known as an AC Cobra, specifically a Cobra Mk III S/C for semi-competition (the street version). Very few of these cars were originally made. This model kit was expensive, but significantly less than the $1.5 million or so a real example costs.

A car much like this was prominently driven by Matt Damon in the 2019 film "Ford vs. Ferrari".

So about 1:8 scale car kits...

There's apparently a cultural style to large scale car kits. They all appear to be similar in some ways, going all the way back to Pocher classic models of the 1970s.

These kits are designed to get a good result by assembly only, without paint or extra fabrication. They are sometimes called a step beyond Legos, and there is a grain of truth to this. Molded plastic parts for this Cobra arrive "ready to use". Only 2 or 3 small parts arrived on sprues. Plastic parts are all colored plastic, or prepainted. Many parts are metal, rubber or other material. Frankly I kind of wanting something that would yield a nice result without a lot of stress.

But a downside to this, to me, is that basically, almost all of the parts are either black molded plastic, black painted metal, silver painted plastic, or silver painted metal. There are a few details in gold or red. The trouble is that all the blacks and silvers are the same, completely monochrome shades over the entire model. To avoid this, I repainted almost everything, aside from the body and other large painted parts that I felt I could not do justice to. So, no, I couldn't just put it together and leave it at that.

These kits are unlike typical scale model kits in many other ways. For one, everything is held together with screws. I used glue only a handful of times. In theory, one could completely disassembly the car again and start over.

The level of detail in kits like this is a mixed bag. On the one hand, pretty much every element of the real car is included. On the other hand, the level of detail on parts is not exactly Wingnut Wings. Parts are a little simple and sometimes crude representations. That's a shame because at 1:8 scale, there's isn't much on a car model that too small to represent. 

Of course on the other, other hand, at 1:8 scale it is pretty easy to greatly improve the look with even a small amount of effort, such as with painting of details. I don't know why 1:8 scale kit makers are so shy about glue, paint and more detailed polystyrene molding. I added several bolt head, some metal straps, fittings, and a handful of other parts. Someone so inclined could turn a kit like this into a masterpiece.

These kits tend to use ABS plastic, I think it is? I guess it works well on large parts. There was no warping at all, anyplace. The plastic is hard and strong, and it paints easily. Parts molded in black look painted. The color is highly saturated with no "transparent" appearance. In some cases, looking to get a variety of shades, I just sprayed the black plastic with a matte, semi-gloss or gloss clear. The plastic can be hard to glue. I did not use much glue, but when I did I ended up working for multiple types. CA glue was not always a good choice.

Features of this kits specifically...

The model includes working steering and suspension, LED headlights and taillights, break lights light when the break petal is pressed, and the car makes a V8 engine sound when the accelerator is pressed. 

I particularly like the suspension. It it will matched to the significant weight of the car. When you pick it up or put it down you can feel the springs giving just the right, realistic amount of support.

The engine sound is fun, but in my opinion, if you can't make it really roar, as this car should, effort might have been put on something else instead. The lights are good, but I should have substituted brighter headlights. You can get LEDs now that are the sort used in flashlights, really bright.

The car also has a working horn sound though. That's a nice touch.

The seats came in a form I have not seen before. They are a leather-like material over a foam layer that stretches over a plastic frame. It has a realistic look, and is "plush" to the touch. I feel it's a little out of scale though, and it is hard to get the right shape to the seat overall. My favorite way to do seats is still covering the plastic with leather as I did on my Eaglemoss DB5 model.

There is flocking-like material on the interior floor. It works well. I added black doll-house scale carpet to the truck interior.

The doors open, with authentic operating latches. The windscreens are all hinged.

The engine looks pretty good, but I wish I had substituted some real rubber hoses for the shiny ones the kit includes. They're not a realistic color, and they are all exactly the same color, being the same material. I added hose clamps where the kit did not, but I saw them in reference photos. I left the kit's molded hose clamps, painted as needed.

The kit used the same hose material for the ignition wires. I substituted some read wire for that. My wire may be too small, but the kit wires were definitely too large and looked exactly like all the hoses (since it was).

A lot of stuff under the hood could benefit from a PE set, or just some simple fabrication that I didn't do.

Overall impressions...

The kit went together almost entirely easily. There were a handful, like 2 or 3, parts that did not fit well and had to be adjusted. The molding quality was good, but molded parts did have seam lines and showed where they were cut off a sprue. These artifacts were generally well hidden. But they were not a factor for me, I fixed them all and repainted the parts. There were a couple instances where the hole provided was simply not large enough for the needed screw, but I got through it, not a big problem. More importantly, all the holes lined up and all the pins were in the right places. Even after almost all the work, no errors compounded enough to prevent the entire body (all on piece) from fitting into place.

Some parts include printed details, such as text, like the gear layout on the knob of the gearshift. These details are completely crisp and add a lot to the model.

I think I counted two minor errors in the instruction, which are provided online as PDF files. In a couple places, the wrong screw was called for. It was easy to spot the error and see what to do instead.

Designers of kits like this like to play a few tricks on builders. There are parts they send at very early stages that you don't use until much later. Usually this is no problem, but for example, at a very early stage I added a bracing frame to the firewall on one side. On nearly the last stage, a corresponding brace gets added to the other side. This part was trivial to put in place at the early stage but adding the other one after the body was on the chassis and most of the hoses were in place in the engine bay was a road to near madness. Somewhere someone's having a laugh.

For some reason the steering does not work well on my model. I'm not sure what's going on there, but it seems the U-joints kink up or something and bind against the frame. I'm not going to worry about it.

The paint on the main body is outstanding and it's why I really like large scale kits like this. There's no way I could create a finish like the model has. When the body arrived and I opened the box, I got a little worried. You really don't want to mess it up. It was handled with extreme care. And again, for all the wishing there were more tiny details, at this scale, one tends to stand back a bit and take the whole thing in. And the body work just steals the show. It's flawless.

It's hard to take photos of this model that capture the size. Now to find a good place to put it...

To look over the history of this build start here with part 1.

Find all of this project's posts here.

The whole photo album for this build is here.

Agora Models Shelby Cobra, Part 7

The electrical setup in the car is a bit messy. But for one thing there's too many connectors. Of the "extension cables" in the kit, 4 are completely unnecessary and I didn't use them. Fewer connectors, fewer things to go wrong. There wouldn't need to be any extension cables if the wires where long enough in the first place.

If I did this again, I'd redo all the wires with things soldered together, and find a better way to route them. As it is they show under the transmission under the car.

Just the same, the body went on OK and it looks great! Also, all the electronics work!

The steering is a problem though. For some reason the steering shaft seems to kink up (it has 2 u-joints) and wedge against the frame. I'm not sure what';s going on there. I will probably just not worry about it.

There's still quite a lot to do including several details under the hood and the iconic exhausts on the sides. The exhaust pipes were in the very first shipment as I recall, but I didn't put them together as I knew they couldn't possibly be needed for a long time. It turns out that they are the very last step.

Part 8, the completed scale Shelby Corba from Agora Models!

Read all the posts on this project here.

Number 12!

It's here at last, the finally pack of parts for the 1/8th scale Shelby Cobra. Completion is eminent.

Read all the posts on this project here.

 

Have a Seat

 

Shopping

 

Agora Models Shelby Cobra, Part 6

 

I haven't posted the details of several sub-assemblies on this project, just because they weren't eventful. They just went together fine, and I didn't do anything unusual with them. I did "dull" some of the chrome, but that's it as far as I can remember.

Here's the hood, trunk lid, doors, other parts... It's coming down to the wire on this project. I may be completed by next month.

Part 7

Read all the posts on this project here.

Lilly Tomlin

 We're The Phone Company

Lines

 

Welches