Hi,
managed to pick this great amp up for free (with full system) but it
has started to play up.

one and sometimes both channels fuz and cut out itermitantly. It
seems to be worse at low volume settings and will usually cut in
during peaks such as kick drum beats or when the vocals start. my
best bet is perhaps a capacitor in the power amp stage has failed but
which one?

i have checked for dry joints as best i can and there also does not
seem to be any speaker protection relays that may be playing up.

any help?

wrote in message
ups.com...
Hi,
managed to pick this great amp up for free (with full system) but it
has started to play up.

one and sometimes both channels fuz and cut out itermitantly. It
seems to be worse at low volume settings and will usually cut in
during peaks such as kick drum beats or when the vocals start. my
best bet is perhaps a capacitor in the power amp stage has failed but
which one?

i have checked for dry joints as best i can and there also does not
seem to be any speaker protection relays that may be playing up.

any help?


Speaker relay contacts. They might be cleanable or the relay(s) can be
replaced.

Mark Z.

This can be from the protection relay being defective, or from some
components in the output stage, and or driver stages, and or the power
supply section, that have gone slightly off value from age and use.

--

JANA
_____


wrote in message
ups.com...
Hi,
managed to pick this great amp up for free (with full system) but it
has started to play up.

one and sometimes both channels fuz and cut out itermitantly. It
seems to be worse at low volume settings and will usually cut in
during peaks such as kick drum beats or when the vocals start. my
best bet is perhaps a capacitor in the power amp stage has failed but
which one?

i have checked for dry joints as best i can and there also does not
seem to be any speaker protection relays that may be playing up.

any help?

In article . com,
wrote:

i have checked for dry joints as best i can and there also does not
seem to be any speaker protection relays that may be playing up.

Most Marantz amps of the era did use protection relays - often they had
opaque grey or black covers, so they may not be immediately obvious when
looking into the case. It does sound like a classic relay problem. DON'T
put any kind of cleaner or liquid into a relay, you'll wreck it. Same
goes for sandpaper. Just slip a piece of uncoated writing paper between
the contacts and jiggle it up and down to dislodge any dirt. Sometimes
arcing wrecks the contact plating and you have to get a new relay.

Of course standard procedure in rehabilitating a 20 year old amp is to
put a shot of DeOxIt into every pot and switch, and work them a couple
of dozen times each.

Do make sure you check the DC voltage at the speaker terminals before
hooking up any decent speakers - anything above 50mV indicates that the
offset needs to be adjusted, otherwise you end up passing a steady
current through your speakers which can make them liable to burn out
their voice coils. If you see an initial large voltage which drops away
fairly quickly, the outputs are capacitively coupled and you're OK.

Cheers, MK.

--
Posted via a free Usenet account from http://www.teranews.com

On Sep 29, 9:12 am, Matthew Kirkcaldie
wrote:
In article . com,

Cheers guys.
Just wondering where the protection relays would be positioned if they
were there?

Thanks