Carlsbro GRX7 mixer amp

[sim]

Carlsbro GRX7 mixer amp schematic would very use full as mine blows fuses and I think it has incorrect transistors fitted
thanks

[oc disorder]

Hi Sim havn't got a schematic but found this info which you probably
have already seen
Diverse Devices, Southampton, England
Repair Briefs 2 , A to M
Carlsbro GRX7, 1996
Sometimes failed to work and sometimes dropped in power
and crackles.
All the 1/4 inch sockets needed attention, front and rear.
The signal pa/preamp interconnect lead needed attention
The subsidiary +rail 156R dropper needed replacing.
Uses 4x MJ15024,
2x SM2177A, 2x SM2178A, CBC182A, BC212
1C03 , 2x TL071
156R, 5x R33, 10R,2x 4R7
Mains primary 6.9 ohms
uses +/-15V regulators on preamp

[oc disorder]

After finding your other post I checked the Peavey cross reference chart
SJ-6343 83180 MJ-15024 70483180 NPN 180V OUTPUT
so perhaps the SJ63438 is a SJ-6343 which is an obsolete TO3 equivalent
to the MJ-15024.
Obviously something major is wrong to blow the 6.3A fuse .
A typical fault is a collector emitter short in the output transistor(s)
- blows the fuse- new fuse put in- driver transistor can't cope driving a shorted output - it and the fuse blow etc etc.
If the blown fuse is dark and splattered it's most likely the output transistors
Disconnect the power amp from the mixer/power supply first make sure you are on the right track and that the power supply and mixer are ok.
The MJ-15024's are found in a lot of high power amps in the past and are one of the few solid replacements for a lot of obsolete NPN TO3 transistors.
The schematics may come to light after the "receivership" is over but that may take a while !

[Enzo]

What am I missing? Where did the SJ numbers come from?

SJ numbers are house numbers printed on parts for the amp maker. it is dangerous to try and assume they are part numbers. SJ6343 is a Peavey number and would not have been assigned to some other OEM as well.

Of course someone could have put a PV part into this thing as part of a previous repair.

[oc disorder]

Hi Enzo
this may help http://music-electronics-forum.com/t17502/
I suspect they were used (the SJ's) in a previous repair.

[ueman]

hi
that uses transformer this amplifier?
thank you...