Hi All! I am trying to fix this power amp. It is the hybrid model put out by Fender in the early 1990's. The amp will not power up. Here is what I've checked so far.Transformer secondary readings in circuit (to ground). Both red + 2.43 vac/ Yellow =0.003vac/ Both blue+ 1.2vac. Also the amp really lights up my current limiter. Out of circuit the readings are: R to R = 136.8vac/ Bl to Bl= 68.6vac.
Disconnecting both red wires from the circuit board causes the panel lights to come on. With all the transformer secondaries disconnected from the circuit board the resistance reading from the board connectins to ground are: Both reds= 30k ohms ( resistance was rising like an electrolytic cap does) / Yellow = 0.5 ohms / One blue (CP3) = 8.23k ohms the other blue (CP1) = 43.4 K ohms.
Both rectifiers read good, as do the filter caps. I detected smoke coming from a small power supply board near the transformer circuit board connections at full power (brought up to full with a variac) with the current limiter in line. This board has had parts replaced before. Using a transistor checker Q86 and Q 89 read bad while Q 82 read good. None of the outpuit transistors read good in circuit, but that seems to be typical. They are soldered in so I haven't checkled one out of circuit.
On the preamp side, there is no heater or plate voltage to speak of. Thanks in advance dv
