Its reading .4 volt ac @ the fuse. Yea its dead.
Now what else can cause that to happen other than a dead trafo ? I guess I am pulling that board off today and checking it.
I do have 120+v going into that from the power cord. I will check for blown up stuff, else I guess I need that little trafo. How to find out what its ratings are ?
Cool.
Srinath.
Now what else can cause that to happen other than a dead trafo ? I guess I am pulling that board off today and checking it.
I do have 120+v going into that from the power cord. I will check for blown up stuff, else I guess I need that little trafo. How to find out what its ratings are ?
Cool.
Srinath.
Hi,
In one of the thread you mentioned that the transformer it was getting hot. Does still get hot? Just in case remove the fuse F453 and read the voltage and see if still read zero. Something it is not right. You post that pin 4 has 5.5 volt. That voltage it is coming from the transformer unless the micro it is feeding it back.
In one of the thread you mentioned that the transformer it was getting hot. Does still get hot? Just in case remove the fuse F453 and read the voltage and see if still read zero. Something it is not right. You post that pin 4 has 5.5 volt. That voltage it is coming from the transformer unless the micro it is feeding it back.
13.3 volts ac without the fuse in. And the trafo dont get warm, of course the fuse being in, makes it warm real quick and ... man you are freaking brilliant. Trafo is fine, I got a bleeding short somewhere ... OK more pouring over the schematic, and no damn powering it up till the short if found and fixed ... I'm a bit slow, but I know better than to power up a known short in the amp.
Cool.
Srinath.
Cool.
Srinath.
OK by process of elimination - I think -
The problem has to be in D453, r453, c465, r454, or d458uz5v1.
Why ?
I got 5.5v in pin 4, fed by the other side of the rectifier diode bridge, and that is regulated by the 7806 to 6v I believe.
The d453 etc is in the line straight off the fuse.
I will yank that out and see what it does to the voltage - or I may pull d458 first since the short is to ground.
Maybe also I need to look for a solder bridge, though the solder was all stock factory in that board.
Anyway your ideas welcome too.
Cool.
Srinath.
The problem has to be in D453, r453, c465, r454, or d458uz5v1.
Why ?
I got 5.5v in pin 4, fed by the other side of the rectifier diode bridge, and that is regulated by the 7806 to 6v I believe.
The d453 etc is in the line straight off the fuse.
I will yank that out and see what it does to the voltage - or I may pull d458 first since the short is to ground.
Maybe also I need to look for a solder bridge, though the solder was all stock factory in that board.
Anyway your ideas welcome too.
Cool.
Srinath.
Hi,
My advice is now to check for a short or a low resistance value to ground using the ohmmeter. I would check the resistance to ground at the point between R455 and C466. The D455 and D457 will isolate the reading from the transformer. Check the resistance and post the reading. D453 it is not the problem because it is follow by R453 4700 ohms resistor in series too high to loaded the PS. At this point you have to be careful because the IC451 feed voltage to the micro.
My advice is now to check for a short or a low resistance value to ground using the ohmmeter. I would check the resistance to ground at the point between R455 and C466. The D455 and D457 will isolate the reading from the transformer. Check the resistance and post the reading. D453 it is not the problem because it is follow by R453 4700 ohms resistor in series too high to loaded the PS. At this point you have to be careful because the IC451 feed voltage to the micro.
No need for replacing the zener. U will damage if u remove and power on the circuit.
If u have voltage at pin 4 (5.5V, maybe 5.8V without load) and pin 2(5.1V), then look for the other circuit where from pin 1 returns. This pin 1 will be high(some + voltage near 5V) only when the power good detection and reset circuit works, and then only the relays will remain on.
Gajanan Phadte
If u have voltage at pin 4 (5.5V, maybe 5.8V without load) and pin 2(5.1V), then look for the other circuit where from pin 1 returns. This pin 1 will be high(some + voltage near 5V) only when the power good detection and reset circuit works, and then only the relays will remain on.
Gajanan Phadte
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Tauro0221: I will get that checked tonight.
Gmphadte: I got these readings @ cp458 - Pin 1 was 0 vdc, 2 was 2.82 vdc, and 4 was like 5.5 vdc. Now I got that reading without anything connected to 458.
Ok If removing zener diode and powering up is bad, then I could replace it with a new one and try powering it up ?
Anyway I'll let you guys - Tauro in particular
, tell me what to do, you have been great. What a learning experience this has been.
Cool.
Srinath.
Gmphadte: I got these readings @ cp458 - Pin 1 was 0 vdc, 2 was 2.82 vdc, and 4 was like 5.5 vdc. Now I got that reading without anything connected to 458.
Ok If removing zener diode and powering up is bad, then I could replace it with a new one and try powering it up ?
Anyway I'll let you guys - Tauro in particular
, tell me what to do, you have been great. What a learning experience this has been.Cool.
Srinath.
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