Need help to repair two phase 400 amps

laatsch55 said:
Larry, I don't want you to worry about the driver board..I want you to do what I ask so we can figure out if there are any problems with the back wall or power supply. I will then send you a complete set of outputs and an assembled White Oak Rev A driver board. You will then follow very explicit step by step instructions to desolder the old board and install the new board. The board is one of 4 boards that were built and sent to me as a gift from Dr. Lucitt when he thinned his herd. They did not cost me anything nor will it cost you anything. I have some band new MJ 21194's which are perfect for the 400. I don't use those in 700's so you can have them too. But to do this you must listen to me and do only what I suggest and when I suggest it. I Don't Believe At your present skill level you can troubleshoot the board and repair it. I do believe you can change one out with help.
These boards are also complete with the Phoenix connectors so no soldering is needed to install them, and a wiring mistake can be spotted abd changed without desoldering and resoldering....
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and a wiring mistake can be spotted abd changed without desoldering

Nice looking boards! And I will not make a mistake placing the wires, promise! I will take it slow and easy and send pic's for you to review. Also I would like to use the old board as a learning tool and replace components if they are not to expensive, but only after this amp is complete. I am getting a little excited about learning the how to trouble shoot and repair in electronics. I have rebuilt plenty of motorcycle engines, Extensive work on small block chevy's along with cam timing , carb jetting and ignition timing and port work. It is a great feeling when the projects are complete and spot on. I know that this is much deeper than any of that but I am up for the task! I think in time, with your help and help from other here I will do ok. I may be a bit slower then others but I will get there! I need to learn to slow down and read everything twice so not to miss anything . And last I want to thank you for sharing you knowledge and kindness and I will my best not to let you down.
 
Hello Lee, I placed a bid on a meter and was wondering if we could limp thru the rest of the testing on the back wall using the craftsman? I also ordered the socket head sheet screws. Can you tell me what else we may need? seal pads? Thanks.
 
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Those will come with the outputs...,Those little glass lookin diodes on the 3 tab terminal strips, and the one to the right of those that look like them are next, give em the diode test...
 
laatsch55 said:
Those will come with the outputs...,Those little glass lookin diodes on the 3 tab terminal strips, and the one to the right of those that look like them are next, give em the diode test...
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Ok, I hope these four are correct. Starting from the bank farthest from the power supply

1 open / 544
2 1.663 / 544
3 open / 557
4 open /529
 
Take a pic of what you think is the power supply. Do you have a soldering iron now? And what solder are you using?
 
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laatsch55 said:
Take a pic of what you think is the power supply. Do you have a soldering iron now? And what solder are you using?
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I have a piece of crap one that may melt solder. I have some small gage silver solder and some larger rosin core.
 
LarryD said:
View attachment 23561


I have a piece of crap one that may melt solder. I have some small gage silver solder and some larger rosin core.
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That is the transformer. The power supply consists of the AC line cord, transformer, bridge rectifier, the big caps and associated fuses and wiring. The DC side of the power supply is the rectifier, caps, and wire and fuses. Please take a pic and post of the components I asked you to test. I gotta do this for a bit until I know we are on the same page.

Solder will have an alloy designation like 60/40, or 63/37. Those numbers indicate the lead/tin ratio. Can you find that designation on the solder you are using?
 
laatsch55 said:
That is the transformer. The power supply consists of the AC line cord, transformer, bridge rectifier, the big caps and associated fuses and wiring. The DC side of the power supply is the rectifier, caps, and wire and fuses. Please take a pic and post of the components I asked you to test. I gotta do this for a bit until I know we are on the same page.

Solder will have an alloy designation like 60/40, or 63/37. Those numbers indicate the lead/tin ratio. Can you find that designation on the solder you are using?
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Lee, first of all I had a feeling I was wrong about the supply. yes I have the 60/40 and the other does not say. It is silver bearing rosin core.
 
Everthing in that amp runs around in a circle. There are exceptions, but a component in circuit is affected by all other components in that circuit. Some components we can test in circuit, because the effect of the other componenets do not have an affect on it, or the affection is to small to to matter.


You were not wrong about the supply. In order to be able to communicate effectively we have to talk apples to apples. No biggie, just terminology. The transformer is a part of the power supply, but not the only component of the supply.....
 
laatsch55 said:
Everthing in that amp runs around in a circle. There are exceptions, but a component in circuit is affected by all other components in that circuit. Some components we can test in circuit, because the effect of the other componenets do not have an affect on it, or the affection is to small to to matter.


You were not wrong about the supply. In order to be able to communicate effectively we have to talk apples to apples. No biggie, just terminology. The transformer is a part of the power supply, but not the only component of the supply.....
Click to expand...

I understand. I am taking notes as we go.
 
Yes, those are the ones we were talking about. Those diodes are affected by components on the backwall and by components on the driver board.

Diodes will have some designation to identify the cathode and anode end. A majority will have a black band on one end. The cathode end is "negative" and the anode is "positive" for testing purposes. You have to desolder one end of these to be sure they are good/bad. So pick the end easiest to desolder and resolder.
 
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