[sdiy] My frustration as a technician..

[Terry Shultz]

Hi All ,

Our value of getting Service manuals is manyfold.

It allows us to repair our products is some situations, and it allows many of us to improve upon a circuit or even have a good laugh in some cases.

Having worked at Oberheim, E-Mu, PPG Germany, I can tell you the value of good documentation and schematics.

When I started at PPG, there were no real schematics and revision control was a bit of a problem. No ECO system or real solid owners manuals in some cases. I spent a good deal of time putting those into place and still I am found wanting on how the PAL programs function in the circuit or timing  docs. 

Dependance on SSM or CES chips really are impacting some repairs on availability and cost. Unfortunately these things happen and it really is like trying to keep an old sports car alive and running. (Cars are easier in my opinion).

Many customers of Freescale DSP were wailing on the lack of continued DSP56xxx roadmap. We built the first DSP56001 in 1986 and it has had a good run I think and versions are still being produced.

The real problem is Stand alone DSP's getting fewer in number and are being pulled into SOC devices. Tools for SOC support are even in a more expensive category.

As I get older and my vision no better, I long for through hole devices again. SMT and BGA are needing traces to be so small that I now have to measure length for DDR design on ARM based products.

I think ARM based products will be a good departure from DSP's in functionality but it will be some time before they can perform DSP functions as nicely. 

I started as a tech for Tom Oberheim right after I finished Graduate school at UCLA, much of what I learned working there , I have carried forwards.

I quickly learned that using the tip of your nose was not a good idea for finding warm parts. The fellow next to me got a nice blister that day a part heated up on the SEM he was working on.

The methods of troubleshooting are being lost to board swapping and many shops will not do component level repair anymore for the same reasons listed in this thread.

The projects we all produce , need more documentation and software produced in an open forum teaches others how to do embedded software programming. We all start somewhere.

Just my 2 cents.

Terry Shultz
thx1138 at earthlink.net



On May 10, 2013, at 10:10 AM, Paul Anderson <wackyvorlon at me.com> wrote:

> This is why I like analog synthesizers. They are one of the few things where component level repair is not only possible, but economically worthwhile. 
> 
> Sent from my iPhone
> 
> On 2013-05-10, 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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