Hey all, I snatched a 1060 today for $10. It was missing the speaker(main) switch cover. I fierd it up and only one channel works. Upon opening it it is missing two driver transistors - I about fainted when I realized how I almost smoked this thing. Actually the transistors were there, but in an envelope. So what do I do first??

I think a few deep breaths are in order, maybe a beer, and then think alot, But after that, what is next?

MarkH

Hey all, I snatched a 1060 today for $10. It was missing the speaker(main) switch cover. I fierd it up and only one channel works. Upon opening it it is missing two driver transistors - I about fainted when I realized how I almost smoked this thing. Actually the transistors were there, but in an envelope. So what do I do first??

I think a few deep breaths are in order, maybe a beer, and then think alot, But after that, what is next?

MarkH

There are a lot of transistors in a 1060, can you be a bit more specific? Can you take pictures? How much experience do yo have on this kind of stuff.

We're here to help, but transistors in an envelope is vague.

Start with a service manual and see whats missing from your unit if you can.

I was a mantenance mechanic for many years, however, I did not really delve into the finer electronics as this. I am not afraid of it, and can read a schematic.

The transistors that are removed and put inot an envelope are the large ones that mount directly to the heat sink. Two are there, two are removed. The numbers on the transistors in the envelope are Hitachi 29c897.
I'll forward pictures a little later. The wife says it is my turn to do the dishes. Gotta go for now.
Mark

If you look at the heat sink, the first and the third slot for the transistor is empty.

If you have a multimeter with a diode checker, test the transistors. There are lots of how to guides to do that, if its confusing, i may be able to do a diy for you.

If the power transistors test fine, and are matches for the other side, then you are ready to find the root cause of the problem. It seems the originals were shorted. Either they failed on their own, or something took them out.

Check for signs of burnt components obviously. If there are no signs, go backwards from where the transistors are on the schematic and test each component. Diode test the transistors and diodes, and assume any electrolytic capacitor can be bad (electrolytics are the can looking ones).

Chances are, if the power transistors shorted, they drew lots of power from the components feeding them, and may have damaged them in the process. If something killed the power transistors, then you really need to find that source and fix it.

This description sounds vague, but I don't want to get into too many details before you get some pictures up.

And btw, the left side power transistors died on my sr900g.The previous owner shorted the speaker wires, I did some work on it, found dead components and replaced them. I replaced the power transistors on the wrong side by accident and powered the unit up.Everything fried again and I had to replace all the same components. :stupid:...lesson=be thorough.

Here are some more pics. These are the components that have been physically removed from the unit. They were in the envelope inside the unit. My multimeter is not up to snuff. I will be going out tomorrow to get an adequate unit.
Thanks!
Mark

Here are some more pics. These are the components that have been physically removed from the unit. They were in the envelope inside the unit. My multimeter is not up to snuff. I will be going out tomorrow to get an adequate unit.
Thanks!
Mark

Hmm, I don't have a service manual for the 1060, but the owners manual is in that Marantz database sticky if you follow it. You need a service manual to show you how everything goes, and what could be affected if those Hitachis shorted.

I would suggest cleaning the heck out of everything just so you can see the components much better. You can spot a burnt resistor much better when it doesn't look like dust.:scratch2:


It's unorthodox, but here is what I did on mine
It was dirty
http://farm4.static.flickr.com/3161/2356646783_1646366913_b.jpg
I decided to be courageous and spray everything down with an electronics cleaner I got from these guys http://www.chemtronics.com/home.asp
the stream from the can seemed to clear everything up.
Cleannnnnnn(caps in the second board from left replaced)
http://farm3.static.flickr.com/2290/2357486194_0e9ffa6a01_b.jpg


BTW, it looks like the phono board is missing a screw, just a fyi.


Keep us updated!

Jcricket,
Those mica washers are toast , will need new ones.
Look at the top of the heat sink to see if there is a little black piece under a metal bracket with two wires going to the board . There should be one on each side, can't tell from the picture if it's there.(hope it's there)
Are the sockets just loose from the board?





Second the need for a SM for this model, sorry I can't help you there...




Barney

I've just uploaded the 1060 service manual to the Marantz database. Should be available soon.

Barney is right about the mica insulator. One of them is broken, one of the power transistor will make a short to the heat sink if you use this one.

It looks like the varistors have been removed. I don't see the wires to the small silver holders on the large heat sink.

Mark, you will need to do a complete overhaul of the main amplifier board. Remove the assembly (board + heat sink) from the chassis, and separate the board from the heat sink.

For the rest, wait until the service manual is available on the Marantz database. Gunnyjoe will advice, as he always does, when the manual will be ready to download from the database.

The little black pieces are there. They are not mounted on the heat sink, but I see them and where they should be mounted. The brackets are there too.

The transistor sockets are just hanging loose too.
I have a gut level feeling that the guy that had this just ran it too hard or used a some cheap low impedance speakers and cooked the transistors on one side. I suspect If I got new ones , cleaned the unti, and installed them, everything would be just fine. Going to get a new meter shortly, then I can start checking things.

Mark

If your actual meter is an analog meter (needle), it is perfect for testing transistors. What do you have exactly? Can you show a picture?

You must check the driver transistors (H709, 710, 711 and 712), the emitter resistors for the drivers (R737 to 740, 220 Ohm), and for the power transistors (R747 to 750, 0.24 Ohm).

Take care not to break the wires on the Varistor in manipulation.

Clean the pots and switches, including the trim pots on the amplifier board.

All I have for a meter is a sperry(home depot piece of junk) it is a left over from my days as Maintenace tech/electrician. My old fluke gave up the ghost maybe ten years ago. I will go out today and get a new one.

I am going to start he cleanup now. I'll measure those as soon as I get my meter.

What should the value be on the H709 to H712 transistors?
I'll post more later when I have some good info. Probabaly tomorrow.
MArk

What should the value be on the H709 to H712 transistors?
I'll post more later when I have some good info. Probabaly tomorrow.
MArk

A diode test sends a small amount of power through the junction and tests to see if there is a ~.6 volt drop across. A fluke gives a short beep when this test passes. If there is a continuous beep, the transistor is probably toast.

Thats the best way I can give a quick explanantion.

Im sure someone here will explain better.

Follow this thread for transistor testing:

http://www.audiokarma.org/forums/showthread.php?t=43186

Thanks, EchoWars!