1060 - Purchased, now restoration

Well Paul, I hope you've made some progress with your 1060. After some bonehead moves on my part, I'm in a very similar boat. Last week I had the amp board running great after replacing every component with new parts. Yesterday, I completely toasted R753 in a fiery SNAP, SNAP complete with much magic smoke. You can see the aftermath in the attached photo. I plan to do a little more cleanup of the board and seal it with epoxy before replacing the resistor. The fire also took out R721, R713, C703 and I'm guessing H709 is toast from whatever caused the resistor to burn up. I chalk this blunder up to 1 of, or a combination of 3 things:

1. I over voltaged the amp board when adjusting the pots. My supply voltage at J709 was 71.2 volts, so
as per rule of thumb I adjusted voltage at J713 to half the supply current, or 35.6 volts. Maybe this
was too much for the circuit to bear?
2. I depopulated about half of the preamp board in anticipation of my next phase of this build. Probably
a really stupid idea to fire up the amp with the power leads still connected to the preamp board in this
state. Maybe this further unbalanced the supply voltage going to the amp board?
3. I connected a standalone preamp to the amp section to test for any noise in this section after my
rebuild of the amp board. In my hast to hook up the preamp I believe I swapped input for output on the
preamp. Not sure if this would effect anything as far as R753 exploding but nevertheless, after running
for 5-10 seconds it did just that. The preamp I used is a DIY deal I assembled a few months back. It
had preformed well with a class A amp I had built but I'm thinking there may have been a compatibility
issue with the 1060.

So after collecting myself I'll be putting a mouser order in for a few new parts plus everything else I still need for the preamp, tone boards, and phono board rebuild. I can say I got a little too confident in my abilities up to this point. From now on I will play it safe, section by section, and not introduce any outside factors like not fully tested DIY components. Hope others can learn from my mistakes as well.

Again, Paul, hope you're having a bit more luck with your 1060. Would like to hear an update on any progress you might have made.

Thank you for your help, its good to know you make mistakes too, do not know how I botched this, but I certainly won't let this beat me, not with all the help here.
 
You should be able to bend some pins and get by with it if you are careful. Maybe sleeve the leads to prevent contact.
 
Just to try and put a clear message on the replacement transistors for the Power amp board in Marantz 1060.
It would be nice if someone can confirm these as correct so that anyone who comes after will have another reference


H706,H705 Replace with KSC945CGBU - Different Pinout than normal - (C Suffix)
H708 and H707 Replace with KSA733CGBU - Different Pinout than normal - (C Suffix)
H710, H709, H704, H703 Replace with 2N3440 -
H711 and H712 Replace 2N5416
H701 and H702 Replace with KSC945CGBU Different Pinout than normal - (C Suffix)
 
I'm not that knowledgeable about transistors, but it seems that I see more references around the forum to KSC945CYTA and KSA733CYTA. I looked at the data sheet, and all seem to have the same operational parameters. The only difference I can see is the packing method. Hopefully someone here can tell us the difference and if it matters in application.
 
ksc945 (2).png
I might well be wrong also, seriously, who am I to be dispensing advice. I think it is only the C part that matters, the transistor is the same, but the pinout configuration is different. Hence why I had to cross some legs.
Open to any correction on this obviously.
 
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Ok i have to replace the 18 ohm resistors attached to H713 and H714.
The didoes read 0.9v each when checked with meter - Can anyone confirm this is correct?
I though diodes were supposed to be between 0.4 and 0.7v when checked?

I changed pretty much all the resistors on the board - checking each of them to see if any were damaged in the magic smoke fiasco, so i thought i would just replace them as i went along.

Surprisingly only about a few had drifted
 
Are the germaniums i am putting back in ok? H713 and H714?
If they are not what diode is suitable replacement?
 
Nice progress Paul. I believe the old H713-H714 were thermistors with a resistor attached. This was a factory service item at the time. Now, these can be replaced with a 1n4148 or 1n4448 diode. No resistor needed and they don't need to be attached to the heatsinks of the driver transistors. You can see them on my re-build below.

Also, going back a few posts, yes your list in post #85 is correct to the best of my knowledge. And as you found out the hard way, the C suffix makes a big difference! Hope you got those crisscrossed legs all nicely insulated.
 

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What points do the big filter cap connect to?
Trying to figure the schematic out here, afraid of making a mistake

Update, got it, powered up on dbt with croc clips to make temporary connection, light bright then dim. Nice.
 
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R747 pos and neg of multimeter attached, used r729 to try set to 7.5mv. No effect moving the pot. Heatsink is pretty damn warm.

Updated: Cannot get the bias to adjust properly. Going from 120mv to 0.1. Not stabilizing at all.
Pulling my hair out now at this stage.
 
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Bump, Can someone direct me please, going to reinstall the original pots, I've got a 470k pot on the board instead of a 470 pot!! I have got me a lot to learn folks, what a mistake, yet another in a litany.

Would that cause the bias to jump around like crazy? i could not get it to settle at all really.
I did not think that the wrong value pot would cause the jumping around and not settling on a value, either way i have to remedy this.

Which leg points towards center of the board?
I do not really get how to figure out which leg is the wiper and where said wiper pin goes.
 
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