JVC M90 Repair in Bay Area (maybe Telefunken Studio as well)

[Mike]

Does anyone know how I can find a copy of the Telefunken Studio 1M manual. Again, I have to fix the cassette deck and replace the top speakers I think. The top speakers make a hiss noise even when I'm not playing music....just when the unit is on. I think those need to be replaced as well?

The JVC90 manual has a trove of useful information. The deck will be fixed...I will fix it!!

 

[Mike]

So I have an update:

I called many vintage electronics stores and basically all have stopped with boombox work. This is primarily because people don't want to pay money when the problem is not corrected...which I don't think is reasonable at all. Come on this is old equipment....nothing is guaranteed! Anyways, I was referred to a shop in Berkeley CA. The guy's name is Ying and has a shop on 1467 University Drive. He is great so far, and prices are fair, and he is honest and upfront! Today he opened up my M90 and figured out that I have a faulty board (the green board connected to the deck). He said if I could get that, there was an 85% chance the problem would be solved. He also told me that the tape mechanism is in good condition (except for the front plate that was permanently removed). Anyways, I bought that deck / mechanical mechanism on EBAY. The seller had good reviews for the other m90 parts he was selling, plus it can be returned if it doesn't work. The seller took my best offer of $150 (down from a listed price of $270). Once I get this, Ying will install the new board and hopefully she works!!

As I indicated in my first post, I bought a Telefunken Studio 1M at the same time I bought the M90. For some odd reason I got two of my favorites in a 2 week period, and it took me years to find just the M90! Anyways, I am having some trouble with this box, and in my opinion it wasn't described properly on EBAY (or was damaged during transport). The seller seems very honest, but I don't know what to do. I spent a good chunk of my money and it needs lots of work. I'm going to start a post about this, to see if I can get any advice.

Thanks all!

 

[Reli]

It's good you found someone. First rule of talking to these shops is to tell them you're a collector which means you're willing to pay more than he thinks the item is worth.

 

[Superduper]

Is that place called The Sound Well? And usually that green board can be repaired.

 

[Mike]

Thanks Reli. Yes, I made it clear that this box was my baby, and I would be willing to go pretty far to get this thing fixed. This is my Mona Lisa!

Super duper....Yes it is sound well. Well I suppose Ying doesn't know how to repair the sound board. He didn't provide that as an alternative....but I also showed him I was able to get an entire cassette mechanism when I first met him.

I don't think I mentioned it, but he was working on an M70 when I walked into his store.

 

[Superduper]

The sound well has been around for decades but it sounds like they must have new ownership. I bought a kenwood kr-9600 from them probably 20 years ago. Ying sounds asian, and I don't ever recall any asian techs amongst their staff. But if they continue in their tradition of keeping classic gear running, then it's all good.

 

[Mike]

Ying actually does he work inside of sound well. The sound well stopped doing boombox work, but they recommended me to Ying who operates out of their shop.

It still might be the same ownership and Ying is just helping pay rent.

 

[Mike]

Hey SuperDuper, I want to learn about electronics. My background is technical, but from a macro standpoint. From a micro standpoint (car engines, electronics, etc), I'm horrible.

I'm good at absorbing information, and wanted to know if you have any specific recommendations on books? Maybe even a good youtube tutorial or other video? A friend suggested reading before taking any electronic class, which I agree with. I want to at least get a basic understanding first.

Thanks for any feedback!

Mike

 

[Superduper]

Start here:

http://www.allaboutcircuits.com/

Start with the online text books and read away. There are no shortcuts. Study especially about ohms law. This will build the foundation for almost everything else that will come later. I doubt you will find anything useful here from a practical viewpoint regarding tuners on these old boomboxes. If you get far enough to somewhat master the AC/DC sections, as they apply to audio circuits, and want to move towards RF circuits such as tuners, then there are a couple of books that I can recommend there too. But first things first....

This site has decent online text books, and have video tutorials too. FREE. In addition to the learning resources, there is also a forum section for students to ask questions if there's something you don't understand. Keep in mind though that they will not do your homework for you. YOU need to apply yourself and give an honest effort if you are stuck on something. Don't just ask for an answer and waste their time. They aren't there to give you a lesson, that's what classrooms are for.

But just so you know, not everyone can grasp the concept of electronics beyond +, - and what little knowledge is required to work on wiring up, say car connections.

 

[Mike]

Thanks. Exactly what I was looking for.....and of course I wouldn't ask someone to hold my hand through this learning process...

I had to take physics 2 in college and remember Ohms Law, but since it didn't apply to my degree I lost that knowledge soon after. I plan to take a second look. Well thanks again.

 

[Mike]

So an update and fortunately a good one. Ying in Berkeley CA installed that deck that I bought on Ebay (which some thought wouldn't do the trick, including myself). Once the wires were soldered, the motor just made a clicking noise. Ying thought it could be the belt slipping, but could't be positive. I had him replace the belts, which wasn't the easiest of tasks. Ying actually said he typically doesn't like to do this type of work, but was willing as he could see that I wasn't going to take no for an answer . The deck now works perfectly. He charged me $180 for all the work and it was well worth it in my opinion. Much better than spending $180 and it being all for naught. So excited!

I might end up selling the Telefunken Studio, as I've more than depleted my fun money. Since it is so heavy I'm going to sell it locally in the Bay Area.

 

[jimmyjimmy19702010]

So an update and fortunately a good one. Ying in Berkeley CA installed that deck that I bought on Ebay (which some thought wouldn't do the trick, including myself). Once the wires were soldered, the motor just made a clicking noise. Ying thought it could be the belt slipping, but could't be positive. I had him replace the belts, which wasn't the easiest of tasks. Ying actually said he typically doesn't like to do this type of work, but was willing as he could see that I wasn't going to take no for an answer . The deck now works perfectly. He charged me $180 for all the work and it was well worth it in my opinion. Much better than spending $180 and it being all for naught. So excited!

I might end up selling the Telefunken Studio, as I've more than depleted my fun money. Since it is so heavy I'm going to sell it locally in the Bay Area.

Well done! $180 is pretty cheap IMHO for all the work done - I know he wasn't too keen on taking on the job but giving him another complete deck for parts would definitely make it easier for him.

Enjoy,

James....

 

[Reli]

What type of work doesn't he like? Belts, or just boomboxes in general?

 

[Superduper]

That M90 deck is nowhere near the most challenging one, and if he doesn't like that one (complete drop in replacement deck and all), forget bringing him some of the more challenging ones. Your next bill might be $500!

To be honest, he should have rebelted the replacement deck BEFORE even attempting to stuff and wire in it. It's 30 years old and even if it still worked, the likelihood of a future belt issue is very high, almost guaranteed, if not rebelted at the time of service, especially if it was an $180 service. This is definitely a case where the labor far exceeds the cost of those belts.

When I was wrenching in my young years, I recall one stupid toyota van that required pulling the engine (dropping it from below) in order to change spark plugs. If you came across a job that required pulling the engine, and that car had 125,000 miles on it with the still orig plugs, would you just do whatever service you were doing, and stuff that engine it back in without also changing the plugs when they are staring you in the face outside the car? That's definitely penny wise, pound foolish.

 

[Mike]

Reli, he will do any work and is up front on the probability of a fix. He fixed the motor on my Toshiba RT-8290s deck. So he's 2 for 2. I'm going to keep going to him in future if needed. I definitely recommend him.

I don't know SuperDuper. I'm not going to question his workflow as I don't know how difficult it is to solder 9 wires. He wanted to make sure the motor worked before changing the belt (which he felt was much more difficult). I had the ability to return the deck I bough on Ebay and he knew that.

 

[Superduper]

as I don't know how difficult it is to solder 9 wires.

For an experienced tech with a workbench already setup with tools and soldering iron at the ready.... about 2 to 5 minutes.

 

[Mike]

Got you. So I suppose he did that to make sure the motor worked before fixing the belts. Either way....I'm happy and that's what matters.

I have a couple questions about this box, and can't find answers on the forum:

1.) I want to paint some spotting that occurred in a few isolated locations. I saw blu_fuzz say in another post that I want the products listed below. Is this a good idea?

Grey: 1993 Mazda Code: Z4 (For the front and sides of the box that are gray)
Silent Silver - effect 603899 IE (For the chrome trim only?)

https://boomboxery.com/forum/index.php/topic/18273-jvc-rc-m90-paint-codes/

2.) How are the VU meters supposed to work? Mine changed how they operate as I indicate below. I think mine aren't working 100%.
-When I have the tuner/cassette playing the LEFT meter goes to 100% (since it is plugged in).
-When I have the tuner playing the RIGHT meter goes close to 100%, and bounces around very lightly. Sometimes when I go to different radio stations, the better goes to 0%. Yesterday this Right meter would move significantly with the music power.
-When I have the cassette playing the RIGHT meter is at 0%.

FYI, I haven't used the box with batteries yet.

Mike

 

[blu_fuz]

The paint code I use is really if you are planning to repaint most of the boombox. If you are just using it to touchup a few scrapes then I probably wouldn't because the gloss and metallic are slightly different than the original color.


I would suggest watching the youtube videos for M90s. That will give you a good idea what yours should be doing.

 

[Mike]

Thanks Blu_Fuz. I had a feeling the "spot" painting wouldn't be ideal. I've found some information on youtube. I'll post before and after pictures when I get around to it. Right now just really enjoying the sound. Amazing quality....my new KRK studio monitors don't sound a hole lot better. The KRK's have a better low end. I do think it wouldn't have hurt for move bass on the JVC.

That Telefunken REALLY brings it with the low frequency. I play it low volume with the bass all the way up, and I can feel the vibration significantly.

 

[Mike]

So I went in and spotted painted a few select areas of the M90. There were four areas that were eye-sores for me, and after some relaxation, I said screw it! It took that Mazda Paint Pent that I ordered and applied it to four locations (I didn't take before photos of the best of the 4 "fixes"). I let the paint run a bit and I spotted it down with a paint brush. I didn't use any primers or final coating...just the paint. I bought from an automotive website (0.5oz pen), which I believe I sent out a link for.

Overall, I'm happy. You can tell it was painted over, but its not as obvious. You really need to look at it from angles to really see the paint spot. If you look at the box straight on, I think it looks great. It looks better then it looked before without question...how much?? That's in the eye of the beholder.

What do you think?!?!

I have some spots on the top I would like to paint, but that paint is too faded (presumably from being outdoors) so I don't think it will match and I don't recommend. If I get real faded one night...who knows...I may try