OK, now we wre closer 🙂
Please check the resistance of r230. It should be open. If yes, change it.
Sajti
I think sesebe is onto something....
with 100k across r230 and 100k across r229.
voltage across r230 52
voltage across r229 16.6
voltage with ref to -70
q213
b +2.9
c +2.1
e +2.8
q216
b +2.8
c +2.2
e +2.1
with 100k across r230 and 100k across r229.
voltage across r230 52
voltage across r229 16.6
voltage with ref to -70
q213
b +2.9
c +2.1
e +2.8
q216
b +2.8
c +2.2
e +2.1
sorry, been in other room playing with this monster.
Give yourselves a cheer 😀
r230 was indeed open.
replaced it and now we have...
across r230 34v across r229 34v
-70 ref
q213
b +3
c + 2.2
e +2.9
q216
b +2.9
c +2.3
e +2.2
Give yourselves a cheer 😀
r230 was indeed open.
replaced it and now we have...
across r230 34v across r229 34v
-70 ref
q213
b +3
c + 2.2
e +2.9
q216
b +2.9
c +2.3
e +2.2
I think that you can try with the full amplifier, but disconnect the speakers.
To limit the current in case that are still some other components broken, after you solder back al removed components, you can unsolder the diode bridge (high power) and put in series with + leg and - leg resistor of 10-47Ω/5W (or 2 car headlight bulbs 30-60W).
To limit the current in case that are still some other components broken, after you solder back al removed components, you can unsolder the diode bridge (high power) and put in series with + leg and - leg resistor of 10-47Ω/5W (or 2 car headlight bulbs 30-60W).
Ta for the tips. its night here now.
so in the morning ill check the other voltages etc first.
put in your limiter.
install all parts, and if nothing smokes, ill check some voltages again.
Ill post after ive done that as to how its going.
so in the morning ill check the other voltages etc first.
put in your limiter.
install all parts, and if nothing smokes, ill check some voltages again.
Ill post after ive done that as to how its going.
Gentlemen.
This morning ;
I replaced all 8 of those 47k resistors (if one goes, do the lot for reliability).
I tested voltages - all good.
Reinstalled all transistors and diodes etc - no smoke.
Removed the current limiters in the bridge outputs - no smoke.
Checked voltages - all good.
Adjusted bias - all good.
Speaker offset under 20mv.
Later I will give it a clean and reassemble the board into the heatsink, connect speakers, let it stabilise, recheck bias.
But at this stage, it looks like you have fixed it.
From the bottom of my heart, I Thank each and every one of you
I shall now go away and leave you be.
This morning ;
I replaced all 8 of those 47k resistors (if one goes, do the lot for reliability).
I tested voltages - all good.
Reinstalled all transistors and diodes etc - no smoke.
Removed the current limiters in the bridge outputs - no smoke.
Checked voltages - all good.
Adjusted bias - all good.
Speaker offset under 20mv.
Later I will give it a clean and reassemble the board into the heatsink, connect speakers, let it stabilise, recheck bias.
But at this stage, it looks like you have fixed it.
From the bottom of my heart, I Thank each and every one of you
I shall now go away and leave you be.
Hi,
Congratulations that you was able to fixed the amplifier with some helps specially sesebe for a good troubleshooting adviced.
Congratulations that you was able to fixed the amplifier with some helps specially sesebe for a good troubleshooting adviced.
Some help, HA.
I was completely lost.
I was just a blunt tool in the hands of some very wise people.
And I'd like to think that everyone was able to make use of the others questions and thoughts. 🙂
I was completely lost.
I was just a blunt tool in the hands of some very wise people.
And I'd like to think that everyone was able to make use of the others questions and thoughts. 🙂
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