Yes, now that you have ruled out the power supply, that is where to look
next. I have heard about some Elites that had terrible problems with
noise being induced into the buss wiring, but I have never worked on one
that had that problem.
Two questions:
1) Where are the power supplies in relation to the console? If they are
close to it, try moving them away. It may be their big transformers
inducing the hum into the console. This also goes for any other
transformers in power amps. Also had a problem once, albeit with an AMEK
console, with a the transformer in a quartz desk lamp that was sitting
on the meter bridge inducing hum into the busses.
2) When you say the power supplies are paralleled across the whole
console, you mean that they are being summed together through diodes, right?
best,
Ike
On 1/26/2010 3:37 PM, Matt Syson wrote:
Hi
If it is 50 Hz then it is probably induction from external wiring. PSU
related 'hums' are usually double (100) or triple the mains frequency.
Matt S
BARAK KOREN wrote:
ike hi,
Back to the elite 40 channels 1986 humming issue.
i recapped and refurbished both psu,i changed connectors to NL8 and i
measured 17v on motherboard, so thats fine.
the two psu are connected parallel for the whole console(not like
some modes made ,one psu for each side of the master section).
The mixer is quite when all channels muted.
The hum (about 50hz) appears when channels are ON (faders down) and
is present on all channels.
reading this:
If / when you re-do the PS connection at the board end, it's a good
idea to put in some de-coupling caps on the supply voltages where
they come into the console. About 4700-5600uf at 35-50 volts is good
for the +/-18v rails (two caps total), 1,000uf / 50v for the -25v
rail, 100uf / 100v for the +48v rail. The 36 volt rail is kind of
optional but use at least a 50v cap, preferably 63v if you put
something across it.
Best,
ike
Hi Barak,
Two power supplies makes it WAY more complicated than that.
You might want to check with Mike at Sytek and see if he will trade
your power supplies for an upgraded one that will run the whole
console. Otherwise, we have some talking to do...
I will send the NL-8 pin-out when I get a chance to look for it.
best,
Ike
i still didn't try option one (caps mode on the board side)...
thought you can advice...
Thanx
Barak Koren
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