Supposed to have only a minor problem for repair but there is obviously
(also) a totally black shapeless lump , presumably remnants of a burnt out
capacitor. Marked C17 between F1 and F2 low power rail AC fuses. Anyone know
its value? probably about 1nF, too low a voltage rating? or because it lies
over a power rail track between D17 and C7, coating burnt off. Loads of
these mustard yellow globular Cs around the board

The output relays seem to present a short to the speakers in powered off
mode, have not got to the solder side of the board yet to explore.
RoHS construction, of course may present other nasties when I get there, not
originally forseen.

"N_Cook" wrote in message
...
Supposed to have only a minor problem for repair but there is obviously
(also) a totally black shapeless lump , presumably remnants of a burnt out
capacitor. Marked C17 between F1 and F2 low power rail AC fuses. Anyone
know
its value? probably about 1nF, too low a voltage rating? or because it
lies
over a power rail track between D17 and C7, coating burnt off. Loads of
these mustard yellow globular Cs around the board

The output relays seem to present a short to the speakers in powered off
mode, have not got to the solder side of the board yet to explore.
RoHS construction, of course may present other nasties when I get there,
not
originally forseen.



According to the schematic, C17 is 0.1uF. If you would like a copy of the
schematics, mail me off-group with a valid address that you accept stuff on,
and I'll send them. The sheet that the cap is on, is 372kB. The whole manual
is 2MB. All in pdf.

Arfa

Arfa Daily wrote in message
...

"N_Cook" wrote in message
...
Supposed to have only a minor problem for repair but there is obviously
(also) a totally black shapeless lump , presumably remnants of a burnt
out
capacitor. Marked C17 between F1 and F2 low power rail AC fuses. Anyone
know
its value? probably about 1nF, too low a voltage rating? or because it
lies
over a power rail track between D17 and C7, coating burnt off. Loads of
these mustard yellow globular Cs around the board

The output relays seem to present a short to the speakers in powered off
mode, have not got to the solder side of the board yet to explore.
RoHS construction, of course may present other nasties when I get there,
not
originally forseen.



According to the schematic, C17 is 0.1uF. If you would like a copy of the
schematics, mail me off-group with a valid address that you accept stuff
on,
and I'll send them. The sheet that the cap is on, is 372kB. The whole
manual
is 2MB. All in pdf.

Arfa



acknowledged

Arfa Daily wrote in message
...

"N_Cook" wrote in message
...
Supposed to have only a minor problem for repair but there is obviously
(also) a totally black shapeless lump , presumably remnants of a burnt
out
capacitor. Marked C17 between F1 and F2 low power rail AC fuses. Anyone
know
its value? probably about 1nF, too low a voltage rating? or because it
lies
over a power rail track between D17 and C7, coating burnt off. Loads of
these mustard yellow globular Cs around the board

The output relays seem to present a short to the speakers in powered off
mode, have not got to the solder side of the board yet to explore.
RoHS construction, of course may present other nasties when I get there,
not
originally forseen.



According to the schematic, C17 is 0.1uF. If you would like a copy of the
schematics, mail me off-group with a valid address that you accept stuff
on,
and I'll send them. The sheet that the cap is on, is 372kB. The whole
manual
is 2MB. All in pdf.

Arfa



all 10 parts received, thanks.
I'll probably have to download the user manual of the .de site, hope its not
all in German. To check whether I'm being stupid and mono operation secretly
selected rather than stereo/2 channel operation. Both channel signals get to
the mixer output jacks and the mixer ribbon is remade with both channel
lines intact but there is a break in one throughput before the ribbon, but
punch-in 1/4 socket bypass contacts are ok.

I was being mislead by L & R on the overlay near the mixer/PA umbilical
ribbon CN1. L is the L ch and R is the quasi ground for the L ch, the R ch
comes in nowhere near it. Full signal L and R gets to the PA but only very
low level gets to the R ch PA pre-driver stage, in for some messy opampish
fault finding or false mute, if the power rails are ok.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

A job for tomorrow, take the PA apart again. The muting TO92 J111 FET is
falsely pulling down the signal line, -18V control V on gate dropper of both
channels but not so the gates.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

--
--
N_Cook wrote in message
...
A job for tomorrow, take the PA apart again. The muting TO92 J111 FET is
falsely pulling down the signal line, -18V control V on gate dropper of
both
channels but not so the gates.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/




Not the FET but the gate to ground cap going ohmic, see more relevant thread
on WEEE/RoHS/PbF


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/