Sansui 8080 lamp problem
Ron G.
the lamps started flickering when I turned the volume knob and seemed
to continue flickering at random. Now they are completely out, all of
them except the power meter lights, and the aux and phono lights.
Everything pertaining to FM is out, ie, dial lamps, tuning lamps, and
FM indicator lights. The tuner dial lamps previously only worked when
FM was selected. If I switched to aux. the lights went out and stayed
out until returning to FM. But they are out on FM now, too. All other
receiver functions work properly. I have checked all fuses and they
appear OK. All pots and switches have been cleaned. I measured the
terminals at the FM tuning indicator lamps and got no voltage reading.
Does anyone have any idea on what may be causing this. Suggestions ?
Any help would be appreciated.
Ron G.
John Richmond
was that the mode select switch turned the dial lights on and off depending
on whether the tuner was selected or not. The mode switch wasn't designed
to carry the current that the lamps require so the contacts would burn out.
This problem was corrected in the 8080DB in that the dial lights stay on all
the time.
The repair for the 9090 is to find where the power for the dial lights feeds in
and out of the mode switch. You then bypass the switch so the lights stay
on all the time. I no longer have my 8080 manual but if I remember the
wafer on the mode switch that controlled the lights was towards the back
of the switch. If you look real close at the switch you can probably tell
which contacts are burned.
JohnR
Jerry Greenberg
--
You have either a cold solder, a loose lamp in one of the sockets, a
loose connector (if exists in your set), or a lamp was going bad and
its filament was making a bad contact in the lamp.
In some recievers the lamps are all in series. Check the lamps with
an ohm meter to see which ones are bad, if this is the case. If they
are in series, and one goes bad, the rest will not light up.
I would change all the lamps at the same time. This way they would be
from the same batch, and not be a mix of some with a lot of hours and
others with no hours on them. Being all new from the same batch, they
would also have even illumination.
Jerry Greenberg
http://www.zoom-one.com
--
Ron G.
I suspect that this may be the case. In regards to bypassing the lamp
power around the mode switch. Would this result in all the lights
staying on, ie., FM, AUX, PHONO and dial lamps simultaneously, or
would these lamps have separate power leads ? I am hoping that the
dial lamps for the tuner scale would have a separate power lead.
As far as the switch not being designed to carry the lamp current,
would this be why Sansui opted to have the tuner scale lamps turn off
when another source is selected. The fuse type lamps presently in the
unit are 12V 300ma but I'm not sure if these are original or not. It
seems I recall reading somewhere that Sansui used 8V 250ma lamps. I've
got a service manual on order so at least that may identify the lamp
values.
Thanks for the info.
Ron G.
jric...@satx.rr.com (John Richmond) wrote in message news:<3bc64a8a...@news-server.satx.rr.com>...
Ron G.
Thanks for the info Jerry. I did check all the lamps with an ohm meter
and they all check out fine. I did a visual inspection of all the
solder connections and they look fine also. I will do a double check
though before concluding that the mode switch contacts are at fault (
which I strongly suspect at this point ).
Ron G.
John Richmond
the indicator lights run off opposite halves of the same wafer. For
example the indicators are connected to top half and the dial lights
to the bottom half. I trashed all my manuals when I moved or I would
look it up for you. You should be able to bypass just the dial lights
and then clean the switch well enough to get the indicators to work
like they're supposed to.
Yes, it seems like the Sansui's did use 8V bulbs. The only one I
remember using 12V was JVC.
JohnR