Recent content by tranguru

Have fun !

Here is what I did for my 510 Still trying to fix it - but the drivers seem to work fine.

You are right - I meant MJE15030 and 15031! MJE180 is only for the bias. sorry for the confusion Robin

How did you check the drivers? there is a risk that they test OK with the DMM or battery powered component tester, but as soon as you push hard, the drivers blow up

do you know of changes ?

For the driver have you considered MJE180/181 ? nice project! will follow closely :lurk:

so in the "power supply " of the input transistor. by the way r713 was open. any update on your repair?

Here are the picture. you can see that the orange input cap has a very ESR - about 38 ohm and 90 nf capacitance. the other pictures should that some caps were simply open on the Atlas tester and show a very high ESR on the SR715. Some caps were in very good condition also. Strange actually...

The measurements on the scan are quite close to what I measured in the amp. But the Vcc= 74V I reduced the Beta to 200 I get so getting closer.

do you have a list of known trouble makers? like the 2SC458 you mentioned?

Here is the model I got on a web page .model 2sc945 npn IS=3.577E-14 BF=2.382E+02 NF=1.01 VAF=1.206E+02 IKF=3.332E-01 ISE=3.038E-16 NE=1.205 BR=1.289E+01 NR=1.015 VAR=1.533E+01 IKR=2.037E-01 ISC=3.972E-14 NC=1.115 RB=3.680E+01 IRB=1.004E-04 RBM=1 RE=8.338E-01 RC=1.557E+00 CJE=1.877E-11...

Great catch indeed here is the new simulation: Steve: as you mentioned - not much change. I will re--open up the 1060 I have the bench and measure - this weekend.

Thanks for the feedback!! need new glasses :) not much change. Maybe my 2SC945 spice model is not correct - I found it on a forum - Microcap did not have it.

but is plays the same role as a diff amp - that is why I called the 1060 diff amp. I guess that is the way they cut costs - rather than a true diff amp with transistor+diode/zener based current source in the tail like in the 510 Here I know how to calculate the circuit... as the current in...

You are right !! let me add it - now it does not correspond to what is indicated (hand written) on the schematic, those 14v are 9.963 V in microcap