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Dynacord Powermate 600 mixer amp , 2006

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.

Reply to
N_Cook
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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

Reply to
Arfa Daily

out

on,

manual

acknowledged

Reply to
N_Cook

out

on,

manual

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.

Reply to
N_Cook

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

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Reply to
N_Cook

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

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Reply to
N_Cook

--

both

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

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Reply to
N_Cook

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