I'm not sure how much I understand.
The cap is likely causing the sparking. If so, that's normal.
The transistor that you removed feeds voltage to the drive windings so there should be no drive. What is the voltage from the base to the emitter for the 6488s in the power supply? All should read 0v.
The cap is likely causing the sparking. If so, that's normal.
The transistor that you removed feeds voltage to the drive windings so there should be no drive. What is the voltage from the base to the emitter for the 6488s in the power supply? All should read 0v.
I know, sorry for my bad english..
The measures frome the base to emitter give a floating voltage, can be 1,6v or 0,1.
It's change continuously, in positive or negative voltage too.
Never stable.
Windings transistor is removed, and optos also.
Remote not connected.
The sparking happen continuously, when i put on and take off the +B continuously, one spark per second (with cap mounted)...
The measures frome the base to emitter give a floating voltage, can be 1,6v or 0,1.
It's change continuously, in positive or negative voltage too.
Never stable.
Windings transistor is removed, and optos also.
Remote not connected.
The sparking happen continuously, when i put on and take off the +B continuously, one spark per second (with cap mounted)...
Thanks for diagram 90scaraudio, but i don't understand well.
Is the same of 225?
Self oscillation, i think the only one motiv.
Must i to change all power supply components?
Or need nos Motorola transistors?
I'm waiting for to have the material for some test, but i'd like to know the why about the self oscillation.
A day works ok, and the next day it turn on withouth remote...
Is the same of 225?
Self oscillation, i think the only one motiv.
Must i to change all power supply components?
Or need nos Motorola transistors?
I'm waiting for to have the material for some test, but i'd like to know the why about the self oscillation.
A day works ok, and the next day it turn on withouth remote...
Ok, thanks.
Need time to get me the components.
I have already 2N6488 new, i must to find MPSA06 (or equivalents?), zener and diodes.
Are the two 1N4003 under the trafo? (in the diagram are the couple of 11 turn winding?)
Then i'll take the axial cap too.
I confirm 1N4732A, 4,7v-1W-5%.
I saw in other 225, in this amp impossible to read, i must to remove it.
Thanks.
I had some time to transcribe my drawing into ExpressSCH. Anyone can download it and edit this schematic, make corrections or add part numbers.
There may be errors from when I did this 13 years ago so correct them as needed.
I can't upload the .sch file but message me and I can email it to you if you want.
There may be errors from when I did this 13 years ago so correct them as needed.
I can't upload the .sch file but message me and I can email it to you if you want.
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