I made my own preamp...

[paddyponchero]

I gave this thread up for dead but it seems to have sustained life. Interesting stuff about reworking surface mount. It is still more of a bother to work with than DIP stuff which preceeded it. It does take some practice and if components are too close it can be really tough. This stuff is designed for reduced real estate and repair of it is an after thought.
Surface mount and DSP related parts are not designed to be repaired for the long term. When it breaks its dead. The world of digital components changes too fast and older parts cannot always be found for repair and compatible parts may not exist. If the manufacturer does not want to service it any longer you'll be out of luck depending on the nature of the problem. The rule of thumb for repairs of todays gear is seven years, after that its up the manufacturer.
These days, the newer, digital based, plastic cased stuff with surface mount won't be the vintage gear of tomorrow. When it dies, you won't be able to reverse engineer it to make it work again. Manufacturers want this stuff out of the pipeline and want you to consider new gear. Vintage is vintage. If you can see the components without glasses and its analog, then you can probably fix it for a long time.
We live in a world of throw away electronics now.

I worked in manufacturing repair for a couple of years and even with all the parts and schematics available it's still extremely hard to repair any kind of digital problems. We were working with Sony DSP parts which were extremely sensitive to sync problems even a bit of flux on a cap could throw the whole thing out.

I'm pretty disheartened everytime I have to throw something out, I can fix almost anything but when it's a problem with a programmable part it's straight into the bin. I have a lot of older electronics stuff that the eproms have started to lose their programming.

Spent the last week cleaning up an ancient philips valve stereo amp which I know I'll have for the rest of my days. Hurray for discretes

 

[Kiauma]

Yes, I still work in the computer repair industry - and I love my old bi-amped Magnavox console!


Bob, do you have a link to the referenced pdf at John Hardy's web site?

 

[crazydoc]

These are the only two places I've seen him discuss caps:
http://www.prorec.com/prorec/articles.nsf/files/656897186E8BD823862568D700669DD0
http://www.prosoundweb.com/recording/tapeop/hardy/hardy_15_2.shtml

Here's the pdf on the 990
http://www.johnhardyco.com/pdf/990.pdf

There's a discussion of caps on the last page.

 

[DJL]

The problem with repairing a lot of the newer stuff today is most of it takes special tools like a microscope and etc... so if you don't have a little home lab your kind of screwed.

 

[Bob's Mods]

Thats why I say the gear of today will NOT be the vintage of tomorrow. Esp if it's digital. Anolog with only descrete transistors is a thing of the past.
The digital products offer increased functionality for the price. The downside is if your digital section breaks down after that point when the factory will no longer service the device, you're out of luck as far as getting it fixed.
Everybody seems to using these cheap plastic switches and jacks too.
Cheap pots, switches and jacks, plastic cases, surface mount but yeah, it's such a sexy little box in that EXPENSIVE, colorful package sitting there on GC's shelf --- to catch your eye. Probably made in China too. I think these companies invest more in the packaging of the unit than in the unit its self.

It's been my experience that programmable devices do not loose their memory with time, at least I've not seen this but I'm not perfect. Your problem may be elsewhere.

 

[Flatpicker]

Oktava Mk-319 and some of those MXL mics, but these xformers are of a cheap variety and should not be confused with Lundhal or Jensen.

Actually, Scott Dorsey told me that he ran some test on the MK319 transformer and found it to not be bad at all. Of course, it's no Jensen or Lundahl, but he said it was way better then the ones MXL and others were using. The fact that the MK319 is Russian and the others are Chinese might have something to do with it.

The problem with the Chinese transformers is that they use the cheapest metal they can find for the laminations. You can really soup them up by replacing the lams with Super Qs.

 

[DJL]

I think these companies invest more in the packaging of the unit than in the unit its self.

I too think sometimes the package is worth more than the product itself... sometimes you can't even return a product without the box... what does that tell us... lol.

 

[crazydoc]

This is a little off topic - sorry, but CAD schematics came up earlier in the thread.

Anyone know where I can get the schematic for the M179? It's not in the manual like many other of the CAD mics are.

Thanks.

 

[kiira]

This is a little off topic - sorry, but CAD schematics came up earlier in the thread.

Anyone know where I can get the schematic for the M179? It's not in the manual like many other of the CAD mics are.

Thanks.

I got the schematic for my E200 by writing to CAD... they were very nice and sent me one in the mail.

 

[crazydoc]

I got the schematic for my E200 by writing to CAD...

Egad, do you mean graphite and papyrus? Or email?

Anyway, the schematic for the E200 in in the manual.
http://www.cadmics.com/pdf_files/e200_manual.pdf

How and to whom did you write there?

Thanks