Martaine2005
- May 12, 2015
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Most of the time, it’s not necessary to power it up.
If a short was present with the transistors in and no short with them removed, it’s fairly safe to replace them and power it up.
I always use current limiting bulb (dim bulb tester) to double check on first power up.
If a short was present with the transistors in and no short with them removed, it’s fairly safe to replace them and power it up.
I always use current limiting bulb (dim bulb tester) to double check on first power up.
Thanks Martainr
I had several burnt, shorted and open components. I replaced all those and checked the rest of the components on the board with testers.
I am using a DBT and have the outputs removed.
Currently I have 2 transistor on the negative power side of the board that will get hot after about 20 seconds after powering up. I am not sure if I have a problem or if its because of the missing outputs. The positive side does not heat up.
I had several burnt, shorted and open components. I replaced all those and checked the rest of the components on the board with testers.
I am using a DBT and have the outputs removed.
Currently I have 2 transistor on the negative power side of the board that will get hot after about 20 seconds after powering up. I am not sure if I have a problem or if its because of the missing outputs. The positive side does not heat up.
Martaine2005
- May 12, 2015
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Very difficult to say without seeing the circuit.
Are the required voltages present?
Are the required voltages present?
Delta Prime
- Jul 29, 2020
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No, you will cause more damage.
Why would you do that?
All the above…
Here you go, buddy!
Enjoy.
By the way, have you seen this?
This is what I came up with. The right channel operates fine. These voltages are in red. The left channel is the one I am working on. The outputs are removed and Q9 & Q11 will get warm after about 15 seconds.
[Mod edit: image rotated and cropped for better readability]
Last edited by a moderator:
Update,
Thank all of you for the help. I did power the unit up on a DBT and everything was fine except for the voltage on Q11 & Q10 emitter.
Installed the outputs and powered up again and all voltages were fine. Q11 went from -4vdc to -.6 vdc. Q10 went from 4vdc to .6vdc.
Took amp off of the DBT and powered up on line voltage and again unit operated fine.
Again thanks for the input you guys gave me!
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I beg your pardon if the question sounds stupid: What is a DBT?
Martaine2005
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Dim bulb tester, aka current limiter.
No such thing as a stupid question in my mind.
DBT is a dim bulb tester.
It is nothing but a incandescent bulb wired in series with the equipment being tested. It limits the current depending on the size of the bulb. A
100 watt bulb on 120vac will only allow 1.2 amps of electricity for the connected equipment.
If you have a shorted component it keeps from letting the smoke out.
Delta Prime
- Jul 29, 2020
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Last edited:
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Thanks. I know the technique, only the abbreviation was new to me. You never stop learning
Yes sir, I think there is something that can be learned everyday if I pay attention.Thanks. I know the technique, only the abbreviation was new to me. You never stop learning
Thanks. I know the technique, only the abbreviation was new to me. You never stop learning
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