[sdiy] My frustration as a technician..

[Barry Klein]

It is even worse: the manufacturer does not know how to repair the product
either and they don't go to the trouble of swapping circuit boards - just
trash the whole thing.  The damn schematics are getting impossible to read
due to thin lines and designers trying to put too much on one page.

On the repair: attach the unit to a bench supply that has current limit
capability.  Set the voltage to what it should be but limit the current in
small increments until you find the component that is heating up the most.
That's likely the bad part.  Just did this yesterday on a SMB server
motherboard with a 3.3V bus overload.  An IR camera would have been nice but
my finger worked ok in a pinch.

Maybe just think like most of this stuff started from sand and now is
returning to the Earth where it came from.  With a few exceptions - like
analog synthesizers - most technology products become unwanted - even if
they work - in just a few years.

Barry


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Dan Snazelle
Sent: Friday, May 10, 2013 07:23
To: Jean-Pierre Desrochers
Cc: <synth-diy at dropmix.xs4all.nl>
Subject: Re: [sdiy] My frustration as a technician..

This is a very scary prospect.



On May 10, 2013, at 9:45 AM, Jean-Pierre Desrochers <jpdesroc at oricom.ca>
wrote:

> Let me share with you something I stumbled on yesterday..
> 
> A friend of mine own a TASCAM DR-2d portable digital audio recorder.
> This unit could run out of 2 x AA batteries OR a 5vdc TASCAM original
supply.
> He had the bad idea to use a 'generic' adjustable wall wart power 
> supply that was supposely at 4.5vdc hmmmm...
> Bad idea.. these suplies mostly comes unregulated.
> Too many volts ? bad polarity ? I'll never know.
> The result, the blown unit doesn't power up anymore.
> Ok. That's the start of the story.
> So I opened the unit to find that all the electronics were on 2 PCB's 
> face to face, completely packed with VERY TINY surface mount parts on 
> both sides of each boards.
> First I suspected a shorted protecting diode right next to the supply 
> connector so I started looking around the surrounding parts.. oh man.. 
> microscope job.. then I decided it would be a good idea to order the 
> service manual to get the job done faster.
> TASCAM answered me the service manual was OUT OF PRINT but I could 
> order it and get it by mail after a 2-3 weeks delay.
> They were not very clear about the cost and the way to pay for it. 
> Finaly after around 6 emails TASCAM/TEAC California office gently 
> emailed me a PDF version of the manual for free.
> So I was very anxious to check out the schematic and figure out where 
> the problem could be in the circuitry.
> My reading was very short.. The service manual only contained
> - a brief list of error messages trouble shooting  (worthless because 
> the unit was dead)
> - parts Exploded view
> - parts list
> - small color prints of pcb's
> (both layers on top of each other so not readable) That's it !
> 
> NO SCHEMATICS.
> 
> So the only thing that was left to me was to ask TASCAM the cost of 
> each of the 2 main boards I cool swap for new ones to get the unit 
> working.
> Here is the reply I received:
> Main board#1 $250.00US
> Main board#2 $140.00US
> Plus shipping.
> FYI a brand new unit in its box sells today for around $189.00US !!!
> So here is my frustration explained:
> For short, in the 70's in Canada (were I live) there was 2 types of
electronics courses:
> - 1 year short course aimed for small home and cars appliances repairs
> - 3 years complete course (analog, digital, logic, software, 
> development, etc..)  this course was VERY CLOSE to the engineer's 
> university course  That's the one I chose to pickup.
> In the past 40 years (beside the elect. development I did) I always 
> put my hands on repairable electronics.
> The stuff were made using tubes, transistors, IC's, etc..
> The degree I got out of my course brought me knowledge to analyse and 
> fix blown circuits. I earned experience out of all my findings.
> Now I'm facing a world of BUY, USE THEN THROW AWAY (AFTER AROUND 5-6 YEARS
OF USE).
> We came up to a point where a qualified tech is almost worthless. I 
> talked to a repair store near Quebec City maybe they would have the 
> TASCAM service manual on hand and the repairs man said to me:
> We almost stopped using service manuals on new stuff..
> The techs know what problem comes often on the electronic stuff we 
> sell and they mostly replace complete boards without bothering what 
> the blown part(s) were !!!!!
> Conclusion:
> Now, new stuff can be repaired (when not disposed) by 'REPLACE BOARDs' 
> techs with small knowledge of electronics.
> In the next future, only:
> -repair shops that fix old repairable stuff (radios, music amps, 
> keyboards, etc..) -R&D & electronic design houses will be the only 
> place left for us techs who like to express our WIDE knowledge in our 
> daily jobs.
> 
> Just my 3 cents !!
> J-Pierre
> Quebec City, Canada
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