"The Real Andy" .pearson@wayit_dot_com_dot_au_remove_the_obvious_ to_reply
wrote in message ...
On Fri, 11 Jun 2004 10:54:03 +1000, "Peter"
wrote:
"The Real Andy"
.pearson@wayit_dot_com_dot_au_remove_the_obvious_ to_reply
wrote in message ...
On Thu, 10 Jun 2004 06:07:09 -0400, "Art" wrote:
Foprward / Reverse resistance is normally a reliable rectifier check.
However it will not indicate failure under load, if in question it
would
probably be best to replace the device in question and the filter caps
in
the same circuit. However don't attempt this after a couple "Fosters"
Eh,
cheers gov.
Despite commom belief, Fosters is rarely consumed here in Australia.
In fact, it is the worst tasting beer I have ever consumed, aside from
a few of my experimental homebrewed beers!
PS, I have replaced many a rectifer under the influence of a fine
beer. As suggested though, the test may not prove anything as the
rectifier is not under load on a multimeter. But in my professional
beer swilling opnion I believe that 99% of dud rectifiers can be
checked on a multimeter! 
I am having real difficulties sourcing a replacement rectifier.
Not to mention that if 99% of them can be tested out of the circuit and
this
one checks OK it probably isn't faulty?
It is S4VB20, manufactured by Shindengen in Japan
(http://www.shindengen.com/content.cf...archresults&pr
o
ductCode=s4vb20)
I have tried Jaycar, WES and Farnell, but no one seems to stock it.
I was wondering, if I replaced it with a similarly speced rectifier, how
likely is it to affect the circuit?
Thats just a standard 4A rectifier. Take it to dick smith or jaycar
and find a 4a unit that will fit. IF jaycar's ZR1314 will fit, then
use it.
A long link, but it might work. You may have to cut and paste the
lines as the link may spread itself over multiple lines depending on
your newsreader.
http://www1.jaycar.com.au/productVie...words=rectifie
r&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Ke yword2=&pageNumber=&priceM
in=&priceMax=&SUBCATID=
BTW. As you may be aware, the problem may not be the rectifier, but
with out replacing it, you cant rule it out.
Thank you for the info. Yes, that looks like it will fit in and if the new
rectifier can be a substitute than it is definitely worth trying.
Assuming that the rectifier is not the problem, which probably is the case,
how would one proceed further?
What I mean is that the board is not very complicated but has a fair number
of caps on it. I can replace all of them, but that would be an overkill
with uncertain result IMO.
I followed links around the rectifier (and the cap) and noticed that other
than several ceramic caps there is not much else immediately near by.
There is something that looks like a triac (I don't think it is one though)
and has 1D2Z1 written on it. I am currently researching what it might be.
Other than the caps I can see a number or triacs attached to a huge heat
sink. They have these numbers on them: 7805A and M3101G.
I don't have enough experience, but something is telling me that since these
are under constant heat stress they are likely to fail at some point.
I am not sure how they would affect the circuit though. I thought that is
one failed the whole circuit would stop working altogether.
The way I see it, something is definitely affecting the cap that I replaced.
And I think triacs either work or they don't so the effect of a failed one
would be constant. Is that a wrong assumption?
I must say that this detective work is really quite interesting, plus I am
learning quite a bit along the way. :-)