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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

Microcap simulation:

Hi team, I tried to calculated the theoretical voltages to expect on the 1060 diff amp. but I was not able to do so: I don't know how to calculate the voltages such as the 14v between r707 and r709. Any thoughts ? Vcc = 60v I am quite sure I need Ie in H701 emitter resistance = 26mV/Ie -...

I also need one :whip:

Hi I searched for the group on Facebook could not find it. I have a 500 (dead) and 510 on the bench

30V might be enough to find faults. most of the voltages will be x 0.5.

I take the board out and have extension leads so I can power up up the board. do you have a variac to power up slowly? If not put a light bulb in series with the your AC (120V ) - one phase. to protect the unit and yourself a minimum with my power supply, I only have the P700 on the bench, not...

Hi Dankik, where does the schematic come from ? did you redraw them? I love the it! robin

Hi JV, I just finished repairing a 1060 - issues: channel 1 very weak sound + a lot of crackling noise Channel 2 sound level medium + a lot of crackling noise. Preamp - OK I removed the amp board from the unit. with the output elcos disconnected. I numbered all the components I intended to...

Hi Mine has SN: 1625 I read somewhere that about 1000 were produced. still to fix mine... has been lying around for the last 20 years... but still working on my 510 which has the weirdest issue...

that is what I usually use also let us know how it goes