this is my first post. I have a Xtr 275 revision C that is in need of repair. It has a blown fen16c rectifier and some issues with a resistor off the back of the power supply caps. I have a photo that shows the resistor i speak of. Thanks for the help. Would love to work through a full repair and add to my collection. HCCA 250, xtr2150, mbr70, xtr 275? If this is not the right section let me know...
thanks for the response Perry.
thanks for the response Perry.
if the fep16ct and fen16ct chips are removed off of the board the resistor does not burn up, however the torroid makes a very high pitched hiss. What job do these to transistors do? Thanks
Also I have replaced the stock 3300mf 35 v caps with 4700mf 50v's out of a rockford. I noticed that only one of the two terminals on both caps have 12 volts. How is this possible.
Also I have replaced the stock 3300mf 35 v caps with 4700mf 50v's out of a rockford. I noticed that only one of the two terminals on both caps have 12 volts. How is this possible.
Amps torn down on the work bench at the shop. doubt ill have time to get back to it till Monday. And yes Perry, i have checked all the fets. Perhaps my technique is wrong. they all show some form of resistance to ground. however when i get them off the amp(ive only down one channel) they check out. I have read the bcae1.com write up for checking leaky/ shorted fets.
You don't check transistors to ground. You check them between the legs of each individual transistor. You can't check for leakage in the circuit (unless it's leaking badly). In-circuit testing is typically only useful to find shorted transistors.
Pull the MPSA06/56 drivers and check them out of the circuit. Don't pull the outputs yet.
Did the amp draw excessive current when it was burning the resistor?
Pull the MPSA06/56 drivers and check them out of the circuit. Don't pull the outputs yet.
Did the amp draw excessive current when it was burning the resistor?
Perry, which mpsa56's shall i remove? There are quite a few. Ps i haven't seen any 45's? And when i do get them out what is the proper way to diagnose them? thanks.
by the way i do show resistance readings on the 6488's and 6491's regardless of position of legs when on the board. but good when off.
by the way i do show resistance readings on the 6488's and 6491's regardless of position of legs when on the board. but good when off.
yes the second from the left is a mpsa06 and is dead short on all legs. the other 06 and 56's check out ok. i have a small amount of 06's for replacemnet. one thing is i did not mark during removal the first two going from right to left. Are the that the positive rail 56's are closer to the outside of the board?
If i reistall them what is next?
BTW i still doen't have a replacement for the fen16c. is there a recommended alternate?
If i reistall them what is next?
BTW i still doen't have a replacement for the fen16c. is there a recommended alternate?
I don't understand the question. Guessing that you're asking about the locations, from left to right, it's A56, A06, A56, A06.
Reinstall them (replace the defective transistor and the resistor that burned), clamp all transistors tightly to the heatsink, install a 15 amp fuse in the B+ line and power it up. Does the resistor burn?
The MUR1620CTR is a good sub for the FEN1620CT.
Reinstall them (replace the defective transistor and the resistor that burned), clamp all transistors tightly to the heatsink, install a 15 amp fuse in the B+ line and power it up. Does the resistor burn?
The MUR1620CTR is a good sub for the FEN1620CT.
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