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Hi im from the u.k. england i bought this rcf 312a mk1 think! And would love to try to repair it, it did have lim protect light on and the fuse marked for +high voltage connected to mos3 had blown.
I opened it up removed the pair of sap16n p's and two irf940 9140s all tested ok with meter diode check,
So I refitted put a new fuse in and also the speaker and tweeter wires to amp board i cut back and resoldered in as they where very weak flimsy about to snap feeling ! possibly stressed with vibration there good and solid now, so i,turned amp on with light bulb limiter and limit protect has gone out.
The main woofer 12" speaker itself is ok, but has no output!
The tweeter horn works has output but sounds a bit quiet, i was using a light bulb limiter but still didn't want to push volume up more than just over half way waiting on a dummy load i ve ordered,
Also i noticed the idle current 8mv test point checked it and it's off the scale on meter reading around 220mv. I didn't alter the idle current pot in case of a fault elsewhere and there was very little dc on the speaker outputs. 3.5mv woofer terminals
1.2mv on tweeter
I checked the supply rails but I'm not sure what they should be
and checked bridge rectifiers out of circuit tested ok.
-HV AND +HV 164V / to gnd -82hv +82hv
-LV AND +LV 75.2 / to gnd -38LV +38LV
12v rail measures +c68 +11.47v
-c69 -11.56v
Also measured 11.8v on pin 5 of the first op amp 4560 from pin2 xls input
P.s one half the underneath of the pcb has no component markings I'll post schematic I have but again not sure which version I have did a lot of googling and looks like the mk1 the power supply section looks same mine component wise
I opened it up removed the pair of sap16n p's and two irf940 9140s all tested ok with meter diode check,
So I refitted put a new fuse in and also the speaker and tweeter wires to amp board i cut back and resoldered in as they where very weak flimsy about to snap feeling ! possibly stressed with vibration there good and solid now, so i,turned amp on with light bulb limiter and limit protect has gone out.
The main woofer 12" speaker itself is ok, but has no output!
The tweeter horn works has output but sounds a bit quiet, i was using a light bulb limiter but still didn't want to push volume up more than just over half way waiting on a dummy load i ve ordered,
Also i noticed the idle current 8mv test point checked it and it's off the scale on meter reading around 220mv. I didn't alter the idle current pot in case of a fault elsewhere and there was very little dc on the speaker outputs. 3.5mv woofer terminals
1.2mv on tweeter
I checked the supply rails but I'm not sure what they should be
and checked bridge rectifiers out of circuit tested ok. -HV AND +HV 164V / to gnd -82hv +82hv
-LV AND +LV 75.2 / to gnd -38LV +38LV
12v rail measures +c68 +11.47v
-c69 -11.56v
Also measured 11.8v on pin 5 of the first op amp 4560 from pin2 xls input
P.s one half the underneath of the pcb has no component markings
I'll post schematic I have but again not sure which version I have did a lot of googling and looks like the mk1 the power supply section looks same mine component wise