Sharp MD-MS702 MiniDisc Recorder - fixing TOC ERROR or TOC ERRORa with a new gear

The Sharp MD-MS702 was my first MiniDisc device back in the day, and I was so happy to find an untested one on eBay! Unfortunately, it had the dreaded "TOC ERRORa" and couldn't play discs.
Well, I fixed it with a new gear! I know this is a long video (the work took 90 minutes!), but I wanted to include everything you might need to tackle it since it's a lot of delicate work.
Please refer to my blog post for more details!
Chapter markers
00:00 - beginning
1:15 - Disassembly - bottom
2:45 - examining the ribbon cables
3:34 - Disassembly - top lid
4:07 - start removing ribbon cables
7:30 - removing the mechanism
8:18 - getting to the worm gear
11:34 - looking at the replacement gear
12:43 - Reassembly - making room to put the gear back in
20:02 - Reassembly - putting the mechanism back in
24:18 - Reassembly - screwing down the mechanism
24:39 - fixing the slot-in/eject
27:08 - Reassembly - putting the ribbon cables back in
30:18 - Reassembly - bottom
32:49 - Testing
Blog post:
www.technicalinitiative.com/2...
Get the tools you need here:
www.technicalinitiative.com/p...
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修理

[@chuckritchie5506]

This guide was amazing, and I was able to fix my MS702! THANK YOU!

[@TechnicalInitiative]

Oh man, so happy for you! Glad your classic recorder is back in action!!

[@hugoherreradiaz459]

Muchas gracias El vídeo es de mucha ayuda

[@TechnicalInitiative]

@hugoherreradiaz459 de nada! Glad it was helpful!

[@stevenfox7378]

An lnformative video and thanks for sharing.

[@TechnicalInitiative]

Thank you! Hope it was helpful! I just finished another one for a local 702 user.

[@Swallabat]

I watched this excellent video, thought "bugger that it looks too fiddly", and so applied a carefully calibrated series of (about three) light blows to one corner instead with the handle of a pair of scissors of suitable mass, whilst it tried to read the TOC... Surprisingly it worked, and I am reminded that this is actually a really genuine hi-fi bit of kit that sounds really nice and detailed, even through my P.C. speakers.

[@TechnicalInitiative]

@Swallabat - that's hilarious and quite a bit easier than opening it up! I might have a few units I can attempt your method on...

[@Swallabat]

@@TechnicalInitiative TBF I knew it worked when I put it away, so it was worth a go. FWIW After looking through the slot and identifyng which way the sled moved, I picked the rhs furthest away corner to give the treatment to, and was careful not to hit it hard, just percussively. It does seem to do the job, I've been using the MD player all day with no issues whatsoever.. My twenty year old recorded media works way better than cd's burned at the same time too. BEst of luck with yoru units, it might save you a fair bit of work. I HATE disturbing those tiny ribbon cables..

[@henkloorbach]

Oh man! You are a life saver. I dug mine up yesterday and wanted to see if i could put it to use still. But yeah, TOC error and all. I was about to embark on this 90 minute gear replacement video but read your comment. So i hit it a few times, not 3 times like you but more like 20 hefty blows. All of a sudden I hear the inner gears wake up from a good 15 years of hibernating. Hit it a few more times on all sides and we're back in business. I just realized this thing has plug in power on the mic port, so I gained a digital field recorder!

[@NeonElixir]

Sometimes we managed to get iPods going this way when I worked at an Apple Store.

[@paulrod0711]

I have the Sharp MD-MS702, it only works with a power adapter now as the corrosion due to battery leakage damaged the traces on the board and i can't be bothered to wire-ad the missing traces. Was also my 1st MD Recorder.

[@TechnicalInitiative]

Wow - what are the odds? It's a great classic player and of course, has some great sentimental value!

[@ianz9916]

I have one that only works on the battery. Fortunately I have an external battery charger or I'd never be able to recharge the thing although I do also have an MS701 that has a TOC error but still charges the battery.

[@ongkarl]

If the gear is cracked and loose, but not too big a gap in the split, you can try using a bit of loctite to prevent it spinning freely on the axle.

[@TechnicalInitiative]

I have heard of this and I think one anecdote also mentioned super glue. Have you tried it? I'm curious about how well it would work.

[@ongkarl]

@@TechnicalInitiative So I got a replacement gear, but it was loose and spun around (and therefore won't work), but I put a drop of loctite and it fixed it right up. Works perfectly now.

[@TechnicalInitiative]

Thanks for the reply! That's great to know - currently, those gears aren't cheap and "friction fit" may only last for awhile. I'll look into some Loctite!

[@ongkarl]

I used the nonpermanent Loctite Blue 242.

[@TechnicalInitiative]

Thanks! I have a "graveyard" of old Sharps and not enough gears... I'll test that out!

[@chamni63]

😂take it apart-yes,put it together- not in a thousand years😮it's like working on a mechanical watch, very professional

[@TechnicalInitiative]

Haha I felt the same way for awhile - I guess enough experience working on broken ones helped! BTW my friend who works on mechanical watches thinks the stuff I work on is too big!

[@mohindersembi7647]

Wow you are very professional engineer and master 👏 well done can you please kindly help me where did you got the gear from as I need 3 off them and you mentioned the metal gear from RC car do that gear works ? Please waiting for your kind reply Thankyou 😊

[@TechnicalInitiative]

Hello and thank you! Right now, I think the one selling the specific one for this model is Gerry on Instagram (@mdgadgetry) you can message him on IG or find him on the MiniDisc subreddit (www.reddit.com/r/minidisc/) . I haven't had a chance to properly try the RC car gear because the hole diameter was much larger than the shaft so I need to test some bonding methods first

[@NeonElixir]

The 702 was my first as well. It was the one big purchase I made with my bar mitzvah money 😂. I finally decided to give in and sell it because it’s been sitting in the box for at least ten years and I just know I’ll never use it again… of course I got the TOC error. Got someone to print a gear for me and I cracked it during installation. Ugh. I heated it but I guess it wasn’t enough or the material it’s made from isn’t good for this application. I don’t think you’re supposed to use Loctite on plastic, but I’m gonna try it with my old gear and cross my fingers. Great video by the way; it’s super helpful.

[@TechnicalInitiative]

What a great device! Glad to hear about how it was another person's intro into MDs, too! Let me know how that goes. I just bought some Loctite to try on some other broken gears, too.

[@NeonElixir]

Finally got back to working on this again. Threadlock didn’t help but super glue seems to be holding the gear in place nicely. Unfortunately, it still won’t work. I can hear a couple small clicks, but it seems to me like the motor doesn’t spin up at all. Do you have any suggestions or should I throw in the towel?

[@TechnicalInitiative]

@@NeonElixir Ah sorry to hear that - check to see if the motor can move at all w/out any of the gears in place (the flat gear). If the motor is having issues, I've seen some ppl take the cover off and clean/lube that as well, but otherwise it might be time to try something else...

[@NeonElixir]

@@TechnicalInitiative Do you mean check whether I can move it manually or whether it moves when power is applied after pulling the gear?

[@TechnicalInitiative]

@@NeonElixir When power is applied w/out the other gear attached to its spindle. Like at 9:34 in the video - there's no flat gear in place that would transfer the motor's torque to the gearshaft. Make sure the motor can spin by itself when powered on. You may have to do some "yoga" to connect the flex cables enough to allow it to power on and see what's going on (upside down? I forget, but there's a way to operate it while open). I had one that was a gear/TOC issue, but turns out the motor was dying also

[@darkseiddoom]

OMG! I cant wait to try this on my MD-MT15. I never would've guessed it was that tiny gear. Where can I get some of those?

[@TechnicalInitiative]

Hi! Gerry (@mdgadgetry on Instagram) has some but since I haven't opened up an MD-MT15 I can't say for sure it's the same one. I think it's probably the same, though! If you ask Gerry he may have opened one. If you check my website, you can see there are a lot of different types of Sharp gears!

[@darkseiddoom]

@@TechnicalInitiativeWow. Okay thanks for the heads up and information! I'll check out the website. Thanks again! Great video!

[@ongkarl]

Yes try Gerry in Hong Kong. However if you don’t want to spend the $30 for a tiny gear, try some blue loctite 242 thread locker to make the gear not spin loosely on the axle. Remove the gear, put a drop of loctite on the axle and then carefully put the gear back on, taking care not to gum up the teeth of the gear.

[@darkseiddoom]

@@ongkarl what if the gear is split? I already hit him up about the gear and I was definitely looking for an alternative. 12 bucks shipping on that tiny bit, ouch.

[@ongkarl]

@@darkseiddoom Depends on the size of the split. Maybe SOL and need a new gear. Maybe a bit of superglue + loctite will work.

[@IsraelHeldt]

would you have more information on where I can find this gear? What is your size, among other details.

[@TechnicalInitiative]

Sure! You can get one from MD Gadgetry on Instagram. Sometimes you can find a spare from a "dead" device, but most of these old ones are broken/cracked. MD Gadgetry on IG - instagram.com/mdgadgetry/

[@matiasarttin6530]

@@TechnicalInitiative yes,. Gerry Li from Hong Kong! , I also have that gear but made in bronze.

[@TechnicalInitiative]

Hello Matiassarttin6530! I'd love to know more about your bronze replacement if you're willing to discuss! I've experimented a bit but it's difficult to get the right sizing and they are mostly straight gears, not helical

[@luisbargen]

Hola. como consigo esa pieza? Gracias Algún link para encontrarla? Gracias

[@TechnicalInitiative]

Hola! Gerry Li on Instagram and Facebook sells the gear replacements - instagram.com/mdgadgetry/

[@luisbargen]

Gracias por la respuesta! Saludos!