CopyrightSome Our repair service capabilitiesCopyright

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REPAIRS AND MODIFICATIONS TO VARIOUS ELECTRONIC EQUIPMENT performed "in-house"
By Unitech Electronics Pty. Ltd.

Phone: +61 2 9820 - 3555

sales@unitechelectronics.com

Updated March 10th 2018
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CIRCUIT BOARD REPAIRS____Another of our fine list of services.


repair pic 2a

Above is a video box with 50 outputs, seen here monitoring signals on the CRO
( CRO = Cathode Ray Oscilloscope )

repair pic 1a____repair pic 3a

Signals and wave forms being monitored on the CRO ( Cathode Ray Oscilloscope )


repair pic 4a


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Please read this portion now before sending anything.

  As of today, March 15th 2017, unless you provide us with an acccurate circuit diagram of  the goods you 
  wish us to repair, we will not be able to service your goods. This decision was made due to the high amount 
  of customers who have just left their "goods" here, unpaid for and said it is now our problem, without 
  a circuit diagram as they did not wish to pay for work done, nor pay for their present up-to-date service bill 
  and our company time spent on their behalf and any further works to continue tracing out the faults and 
  effecting a great result ie: A good repair.  Not any more. We are out of pocket for these little gems of deceit.

 We will from now on, be requesting for your credit card details first of all to cover the costs. 
 Simple remedy : No card - No work. This decision is final.

  This decision has been implemented by the given rise in losses in company time and of course, loss of 
  income due to failure by customers to pay us.  If your product's circuit board is less than 3 ~ 5 yrs of age, 
  possibly or maybe, if it is over SIX years, up to TEN years, it may be remotely repairable, 
  depending on the  brand, the accurate age, parts availability and how bad it is damaged. If it is over 10 
  to 15 years, then perhaps it is high time buy a new item and get a 12 or 24 or more month warranty.
  
  REWINDING TRANSFORMERS :
  Regarding re-winding of small transformers. We will no longer perform this task, based on the time to very
  carefully disassemble them to carefully study and note the number of windings and what direction they are 
  wound and more importantly, what or why the windings became burned-out. 
  Often the question is asked " why did it burn out in the first place ?" Best guess is it had no thermal fuse.

  These financial losses are costs we cannot and will not absorb. Time spent in carrying out a repair on your
  behalf has to be covered under our company time. Time is money as they say. We are not a charity, nor a
  benelevent society. If you cannot afford to have the item or goods repaired, please choose somewhere else. 
  No " free-bees " here.
  We have expenses and overheads to cover on a daily basis.  We don't want your dead products left here 
  unpaid for as these are re-cycle binned and trashed. 
  We simply do not have the facility to store your dead "junk" per se.

  We do like being paid for the sweat and time searching various resources to locate what a particular part is, 
  in consideration there are literally many millions of electronic parts made since 1970 by many manufacturers  
  of their own devices, some still in business, some are gone or absorbed into newer companies by mergers 
  and aquisitions (aka M & A). 
  Eg: Phillips, then NXP, then EXPERIA and possibly it will alter within the next few  months. who knows ?
  
  The search for electronic component data sheets takes company time, circuit diagrams can sometimes 
  assist in most most cases, a with good and positive result for the items you brought for us to repair are 
  working.  
  That is our everyday goal. 

  There's no-one called Nostradamus working here to make predictions or no-one with Superman's X-ray 
  vision to diagnose your problems by just  looking or glancing at a PCB.  The age old question, how much is 
  it going to cost me ?  
  Hold on,...... where's my crystal ball ?.....  '   It is not a broken cup, it is not a bent table leg, nor is it a
  cracked engine piston.   We only deal in and work in absolutes. It is black or white, no shades of grey.
  In electronics, THERE IS NO ROOM FOR ERROR !  It is an exacting science learned over many, 
  many years.  Try 48 years.

Click here for WHO IS NOSTRADAMUS
So, in re-capping, No accurate circuit diagram, No service work will be done.
____________________ Resolution meeting 7:00 pm 15/03/2017 ____________________



   Above is a " reverse engineered " rough layout of a circuit board by which we had to "trace out" and 
   derive a working electronic circuit layout to effectively service and repair a 30 output  video amplifier
   / distribution box for our client to use and work from.
 
   Someone had attempted (though very poorly) some 10 + years ago, to build a video duplication box with 
   30 outputs with using a now obsolete hex transistor array, which normally under digital or logic switching   
   would function as per the data sheet, however it was very much a different output when deployed as a 
   video amplifier, with odd stray parasitics due to the use of the same chip "die" within the LM3086N. 
   A bad choice of video amplification components by the previous designer of his version of a 30 way video 
   distribution amplifier.
 
   Despite these problems, the owner "struggled-on" for years with a poor resolution output for his Tape 
   Duplication business. As there was no circuit available, we contacted the owner and explained that in 
   order to repair the unit, we would need to devise some form of workable schematic diagram, this was 
   before we discovered the stray "parasitics" and other inherent "noises" within each LM3086N chip. 
   The LM3086N is basically a six NPN transistor array in a 14 pin DIL package. It was good for other 
   types of switching such as controlling relays etc., however, in this application, absolutely not for good 
   video work.
   Six T-05 "metal can" transistors would have been a far better choice and the tin can could be grounded.

   This all takes time to carefully check for 100% accuracy and correct component orientation as well as
   the correct data sheets and identification of each part. The circuit above took 2 hours to trace out and 
   a further 2.5 hours to carefully draw the relevant 100% accurate working electronic circuit. 
   Thus adding further costs to the client/customer's account.

   While this method works fine for a single sided printed circuit board with parts on one side and copper 
   foil on the other, it becomes rather complex when there are two sides to the circuit board and parts 
   cover the track work. Impossible ?  No,...Not always, however, with multilayer circuit boards, there 
   can be as few as three layers, top, bottom and middle. The middle could be a useful "RF" shield also.

   Now comes a new entry into the mix. A multi-layer PCB with four, five and up to 32 layers in a single 
   manufactured PCB.  That is virtually impossible to trace out using conventional methods. 
   A full schematic will help, however, unless you posses the schematics in full, complete with 
   all revision notes, you are wasting your time, and effectively our time also. Costly exercise. It's not on.
   
   Note: The circuit  (above) was "reasonable", however the "LM3086N chip transistor array" exhibited 
   thermally induced parasitics and a basic lack of performance, inherent picture instability, features 
   not conducive to a  client's projected long  term usage in a business where quality matters, in fact it 
   is an absolute requirement.

   This more than likely resulted from aging stock and manufactured in circa 1994 and no longer made 
   by NS (National Semiconductor),  So, after an in depth consultation with our client, it was resolved that
   the unstable circuit boards were to be removed from the Video Duplication Box and returned 
   to our client, we set to and designed a  fresh "new circuit" approach that was to adopted better outputs
   thus providing our client with 50 good solid video outputs from one video input source. Our client was 
   highly delighted with our efforts and paid us accordingly. Times have changed since this was written.
   VHS Video tapes have beed replaced by CDs then DVDs and BlueRay (all three names copyrighted).

   The scrapped circuitry was fully removed and using the fresh new idea and approach, a viable circuit 
   design was skillfully produced, prototyped and tested by us at Unitech Electronics Pty. Ltd. and field 
   tested at the clients premises with all benefits measured in terms of reproduced picture quality on a 
   series of video tapes and the final test of a copy from a copy, this is the "acid test " on how well a copy 
   is being duplicated or made, the results were delightful, however, more importantly, our client was very 
   happy with our efforts and especially with the results.  As a bonus from prototype testing, we were able 
   to include such benefits as 10 stage video signal attenuation to cater for various video input strengths. 
   Not all video tape signals are weak and not all are strong either. This attenuation worked very well.

   Research and development on a project such as this takes time and money, more time and more 
   money usually, however,  the end result is what counts, a very satisfied client, delighted with the 
   extra efforts and attention to detail we took to make sure each video output was fully stabilised and 
   that all 50 video outputs functioned correctly,  thus providing an excellent amplified video signal Video 
   to all 50 outputs simultaneously to each and every VCR (VTR), with no distortion or color 
   fade or drop out, even with the extremely annoying Macrovision copy protection.


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OUR REPAIR SERVICE AND VARIOUS " OTHER SERVICES " LABOUR RATES


P R O T O T Y P I N G


    Labour rates design work  Prototyping ......... AUD $ 150.00 per hour ( AUD$2.50 / Min )..... Plus GST.     

   ( time taken is calculated in months, weeks, days, hours and / or minutes depending on complexity )   


    Please Note : Labour rates do not include any materials or components nor do they include GST. 

    All parts and materials used are in addition to time spent on the client's behalf to get a project to fruition.   



N O T I C E     -     R E P A I R S    -     B E    V E R Y    A W A R E    -     S E R V I C E    -    N O T I C E



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      Please be aware, we are not a " results only company ", that is to state as in " only "
      being paid "only" if the result is goods or equipment works.  We accept  "your goods" for 
      repair or service in good faith, however if it is found at some stage during the repair(s) that 
      the said item(s) for repair or service are not going result in a  positive working outcome, 
      either due to the age of item(s) or component(s) that are " still now " available in stock, we 
      will advise you of the costs so far in arriving at this conclusion. There are no "Free lunches".
 
     All company time is accountable for. This is only fair as where you work, you would not like  
     be NOT PAID as a result of a project or job not working out right and your boss telling you, 
     "tough luck mate...it did not work so no pay for the hours wasted on trying to get it going".


  We require payment for company time spent on your behalf working on your goods or equipment  
  irrespective of the final results that the item(s) in question are working. We strive for perfection  
  in servicing and repairs, however there are times where component tolerances change over the   
  years, thus often resulting in undesirable "hard to diagnose" faults along with stray capacitances   
  and weird parasitics etcetera, plating "growths and spurs" that creep into circuits boards over time.  


This rule ( above ) does not apply to goods or products manufactured by us, here at 
Unitech Electronics Pty. Ltd.  We support all our manufactured goods and equipment 
with quality original backup service components for up to 5 years. (Labour excluded)

There are Circuit Rules



Below is a simple representation of what is involved in taking a simple idea or design,
and building upon that idea or concept, right through to fruition as a completed prototype.


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Flow chart on Ciruits

Above is what is involved in a simple idea or design, taking that
idea or concept through to fruition as a fully completed prototype.



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