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Fostex G16 and G24 Audio Card BAD CAPACITORS !!!!


Almost ALL G16's and G24's have many bad caps in the Audio Cards (and elsewhere).
 
If you have a G16 or G 24 you need to TEST your machine to see if your caps have gone bad....

The easy way is to just record and playback a 50 hertz sine wave at 0VU from your console....
If the tone shows up at 0VU on the G24 in Input, and after Recording it, and playing it back it again
shows up at 0VU (or slightly higher or lower) in the Repro mode.... you're OK

If the 50 hertz signal shows up much lower than 0VU....in INPUT or Repro,   odds are you've got bad caps !!
Same if you have wierd VU meter displays.... a leaky cap can cause VU meter problems....
though the LED style VU Meters can often go bad by themselves.

The problem is that the Capacitors are VERY Early Surface Mount designed caps....
no longer manufactured, and no longer available...
 
This means one has to find replacement caps of the same basic size (each value is a different size)
 
Then bend the legs to position the caps close to the circuit board, and match the solder pads on the boards.

Each Audio card takes something like 36 capacitors that are or will go bad.
Plus all the IC's and Transistors and resistors are also SURFACE MOUNT....

Also the Dolby S IC's are no longer available....
so if one goes bad your tech needs to bypass the Dolby S system on that card...

Any surface mount component is far more difficult to replace than the old standard 'through hole' component.
And it is NOT something that normally can be done on location.....
Your tech will have to take the card back to his or her shop, work under a magnifying lamp, with precise
tools, to desolder the bad component, then resolder in a replacement.
Then try and bench test the repair to insure it is working correctly - very difficult to do with tape Recorder
audio cards since there is Bias and Repro, Record and erase heads to contend with.

SO.... consider the cost of replacing all those caps.... there will be about 900 caps in a G 24   (less in the G16 of course)
and that's hundred's of dollars just in parts, and many many tech hours to do the work !!!



a G24 Audio Card with many bad caps.... - and the bad ones look just like the good ones !!

move mouse over pic for larger view !!!

(Pictures coming soon !)


 
 
Plus if you purchase a G16 or G24 audio card from someone, odds are that there will be bad caps in the card...
 
So.... if you have a G16 or a G24 and it is still working ok, buy a few audio cards and have your tech replace
all the electrolytic caps in those cards, and then have them on hand when your cards go bad.

And test your machine each month for loss of low frequencies - the sign of caps going bad   !!!


 

 

 

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