PL400 Build help
- Thread starter BrickbyBrick
- Start date
BrickbyBrick
I would stop now and Wait for the expert Joe.
Joe do you think he should flip the RT back plain board and inspect the back of the board?
it appears it the RT Board and RT Q3 had a bent pin and shorted to ground
the bad news is he was sparks in the RT board, Lower left corner.
he found 1-bad one and w this test you can only test for bad ones. (does not mean the other ones are good)
thanks
Steve
I would stop now and Wait for the expert Joe.
Joe do you think he should flip the RT back plain board and inspect the back of the board?
it appears it the RT Board and RT Q3 had a bent pin and shorted to ground
the bad news is he was sparks in the RT board, Lower left corner.
he found 1-bad one and w this test you can only test for bad ones. (does not mean the other ones are good)
thanks
Steve
At this point, you need to know what transistors are good and which are not good.
Find a friend with a meter capable of doing accurate diode checks and test all the transistors. Sort good from bad After that you will be able to proceed with back wall transistor addition.
You can check out the control board to ensure that no damage was done to that in the mean time. You do not need any transistors in the back wall to perform those tests.
Find a friend with a meter capable of doing accurate diode checks and test all the transistors. Sort good from bad After that you will be able to proceed with back wall transistor addition.
You can check out the control board to ensure that no damage was done to that in the mean time. You do not need any transistors in the back wall to perform those tests.
Recommend you also stop and build a DBT before proceeding further. With the DBT in series, you cannot wound the output transistors as you can when you blow rail fuses.
All the builders invest in them to ensure successful bring ups. There are many pictures on the web when you search for DBT on what they are and how to quickly build one.
All the builders invest in them to ensure successful bring ups. There are many pictures on the web when you search for DBT on what they are and how to quickly build one.
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- music...the healer of souls...
i dont know where you are at this point...maybe waiting on a set of outputs ....
i would like to relay a recent problem i had to deal with....i was installing a meter sensitivity switch in my wopl 400....when i did not notice i had about an inch of unused solder laying on the back of the faceplate....i did not notice it when i put the face plate back....i carried it into the den...by the rack handles....that solder fell on the left back plane ....
it blew 4 outputs on the left side....4 emitter resistors...and 2 one ohm resistors r1 and r3 i think....and of course the rail fuse...
after replacement i could not set left bias...with joes help i located the problem on the control board....q7 and q8 were not up to par....
according to joe...they are a safety thing...and the amp is working without them....the replacements should be here this week....
the point being...you may have other problems....be careful....be thorough...use the dbt...and be careful torquing the outputs....one snug too much and you will blow fuses again without a dbt...last one i put in...i had to back up a bit...no damage done....thanks to the dbt...and it is back to playing and sounds spectacular...
good luck...
i would like to relay a recent problem i had to deal with....i was installing a meter sensitivity switch in my wopl 400....when i did not notice i had about an inch of unused solder laying on the back of the faceplate....i did not notice it when i put the face plate back....i carried it into the den...by the rack handles....that solder fell on the left back plane ....
it blew 4 outputs on the left side....4 emitter resistors...and 2 one ohm resistors r1 and r3 i think....and of course the rail fuse...
after replacement i could not set left bias...with joes help i located the problem on the control board....q7 and q8 were not up to par....
according to joe...they are a safety thing...and the amp is working without them....the replacements should be here this week....
the point being...you may have other problems....be careful....be thorough...use the dbt...and be careful torquing the outputs....one snug too much and you will blow fuses again without a dbt...last one i put in...i had to back up a bit...no damage done....thanks to the dbt...and it is back to playing and sounds spectacular...
good luck...
