Plastic ring gear failure

I have no repair sugestions. This same crappy plastic gear molded onto sheet metal was a problem with the sony professional walkman lines.

I finally trashed my last one after replacement parts were not accessible. Even if some are in a warehouse somehwhere, in yellowed plastic bags they're certainly cracked as well.

The other problem is they used some sort of that bright white and very slippery plastic. Nothing seems to adhere to it, which is why I gave up.

I really liked the WM-DC2 otherwise.

this m/c has been stored in the studio over the years, so no extreme hot or cold. So as no sign of rust , either the plastic shrinks with age or there is stress set into the plastic when formed around the steel and then the plastic weakens with age

Probably both. As you're seen the crack starts at the bottom of the teeth where the stress is highest and it seems impossible to squeeze the gear back into shape, so it's not just a plain old crack, plus there's just not enough power on portable tape deck to split gears apart in the first place.

On one forum I came across there is talk that the gear in the walkmen may have been polyethylene, matching the issue where you can't glue it. another person says delrin, which explains shrinkage over time.

I even considered drilling holes into the area around the cracks and wiring them together to bridge the gap, but there just wasn't enough space, material and give to work with.

Too bad "3d printers" can't make truly useful parts yet.

They can, and you can get entire working setups for less than $500 these days. They are the bare printer, no fancy looking box or case that looks like an HP inkjet.

They work so well that someone in Texas, where it is legal, made the lower receiver of an AR-15 assault rifle with one. His first attempts shattered from the forces of firing one round, he has YouTube videos of making one that lasted over 100 rounds.

Sounds pretty "useful" to me.

What somebody needs to build now is a 3d scanner, which will take an object, such as a cracked gear, and produce a file of commands to the 3d printer to get it to make a new one. It would need some fairly sophisticated software, so you could make multiple scans (such as one lying on the top and one lying on the the bottom) and combine and correct them.

Geoff.

Something like this:

At work we have a 3D-scanner that can use reference dots that are placed on the object for combining multiple scans of the same object into one

Shaving back the steel allowed resetting the ends, a ring of heatshrink around and carefully heated the heatshrink , only, with soldering iron and glued around whole disc/plastic join. Looks a goood , non-jamming and non-oval repair, will see tomorrow, get it back in the deck

I thought of one use for a 3D printer. Making false teeth. Taking dental cast, multi-scan and stitch to get a 3D computer model, patch in via copying sections for missing teeth, take negative mathematical casts wherever necessary. Break such a set of false teeth then easy to generate a replacement from the mathematecal model. Unfortunately a 3D printer cannot do what is so easy with a 2D printer, colour up the resulting false teeth to colour match.

As a 3D printer is about the cost of a set of false teeth, I can see walk-in High Street agencies producing false teeth almost while you wait, perhaps in the next 5 years. Perhaps a secondary melt-mixing stage to add pc controlled dyestuffs to the melt to colour up the teeth/plate at the generation stage

Back to the original problem. Laces and unlaces and plays , FF and REW ok. Looks as though the gear broke over time in storage. The PCM legend flickers randomly and no sound out, no 6ch VU bargraph display , the original problem. Not tried playing a video tape but I expect no picture either. Other than cleaning all tape running surfaces , anything to check for? does not like PLAY+REW drops out. Reminds me of Beta video failure mode, usually slip clutch problems ISTR

I decided to inspect under the deck, easier than first seemed. Now with a better viewing angle for the heads, one of the 3 is broken.

You've obviously never seen these machines in person. The outputted parts are pretty horrible by an measure.

No $500 piece of junk can make the usable gears for the OP's problem or a walkman.

this stuff exists, they had some at the MD&M show in Chicago last week. Still, no printer anybody could afford will produce usable intricate parts, and they won't be of the type that dribbles a plastic ribbon on a crooked warped table.

I don't want to send you on a wild goose chase but have you double checked the power supply voltages as the deck is running and under load?

I have one of those Pioneer D70's I mentioned in the earlier post, never really used the deck for video as much as that 6 channel PCM function, that allowed you to record up to 24 hours of continuous audio, in the LP mode. Was handy for talk show marathons and other crap worth recording back when the 10 foot satellite dishes were considered home entertainment.

A few years ago being those decks are as rare as hens teeth with that function (there was some RIAA legal threat, later models kept the PCM but dropped the 6 track feature), I decided to dump the 50 or so cassettes to digital and make mp3's out of them.

Since it wasn't used in years, it sort of worked but died after a few days with similar symptoms, some of the display wasn't lit, other parts were and trying the either forward or reverse scan kicked it out of the play mode.

For some reason I started to look at the STK module, which I think was bolted to the back of the unit and discovered it was working but "sagged" under load. Almost like a capacitor problem, would put out the +12v until you hit play, then it sort of dropped to 9v and somewhat came back up to the

I was able to cobble together some discrete parts that replaced the bad functions of the STK (not available from what I remember) and was able to finish up the tapes, but it did include a lot of finger crossing every time a new tape was put in.

I'm just recommending to monitor the voltages before tossing in the towel, it's easy enough because I think that whole power supply module can pop out and rotate around and the output voltages are clearly marked on the board.

-bruce snipped-for-privacy@ripco.com

I like it!

I watched a utube of them making false teeth the traditional way, no wonder with so many intermediary stages , they are so expensive. With such a mark-up I can see 3D printing come in there with a wallop, like the 2 bucks reading glasses that started coming in 10 or 15 years ago, wheras previously there was only expensive opticians scripped reading glasses

the utube