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Transistor probably shortened, need ugent help

dario54

dario54

Member
Today I was reinstalling my beloved 2265 which came back from the tech repair for few small substitutions (power switch and some fuction lamps) into the tight niche where I alowed to put my audio equipment.

Connecting all output and speakers cables, with the power switch in OFF position but the unit still connected to the power, one end of the phono cable touched the top Motorola transistor, causing a total blackout at home.

The transistor itself, placed on one of the heatsinks, has Motorola 0555 written on it.

I cannot identify it on the part list of the user manual.

If, as it seems, this transistor is dead, where I can buy a suitable part?

If it'is dead, changing it, should I change the one on the other channel too?

Other suggestions?

Thanks in adavance...

PS My 2265 is a multivoltage Marantz, unit, probably sold originally in Europe (Germany?).
 
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You're saying power was off and the phono RCA cable somehow touched an output transistor? Had the amp just been powered on or had it been off for a while? Can you post a photo of the part in question? Seems like it'd be hard to tap a transistor unless the case was off of the receiver. Not quite clear what happened.

Sounds like you didn't test the transistor yet. If you're lucky, maybe you just blew a fuse. I'd check fuses first and then start testing parts. Odds are that if the output transistor blew, it took some parts from the driver board with it.
 
Im kinda curious WTH the phono cable was plugged into...

If we assume the case of the TO3? had a switch off path to ground (more than likely it was the frame of the unit) then the shield of the cable must have had a path path to ITS ground which was the other leg of house power. non polarized stuff sucks eh?

TOTAL blackout at home? meaning the service entry breaker tripped? unless you live in an old shack with a 30-60 amp main, thats at least a 100-150-200 amp breaker to open up. That much current - if it happened - likely welded a lot of stuff inside both units.

Id say, before you worry about the turntable and amp, you get the house wiring checked why a single, or even double wall outlet failure took everything down *first*
 
Not the WHOLE house, just the breacker for room where my audio stuff is connected, I live in Israel, we have here 230v/50Hz...ALL the breackers are new and istalled recently by a certified professional...so the whole electric system is up to the latest requirements...I checked the main fuse on back of the unit, visually seems good, since it's the multivoltage version, thre are 2 other fuses that can be accessed from the bottom, but have the time to dismantle all.

I noted on the external metal body of the transistor, there's a little indent where the phono cable touched it...just near the top screw.
 
It might be inportant to know whether it was "just a circuit breaker" or a ground safety breaker (one you usually have to push the button first before being able to switch it on again). At least, in a new home I do expect a ground safety breaker, but it can be a main one to feed all others, too.
If it was a ground safety breaker, you MIGHT have a serious problem with your equipment, as low dc or ac current gets detected.
If it was a normal breaker, you DO have a serious safety related problem with your equipment (for example, a mains wire in turntable or amp shorted to ground) as only a lot of current can do this..).
The second case, you at least need to find some reason for tripping the fuse....
 
I do not know how to explain myself.

What I have in my electrical box is a group of breakers, one main, and several other for single rooms or areas of the appartment, plus one for the kitchen. one for the main air conditioning and one for the water heater, the latest with higher Ampere values.

Only the breaker controlling the room with my audio system shut off, when the phono cable touched the transistor there was a spark quite strong, but no burnt smell or similar and the power wen down ONLY in that room.

Never had any problem using my audio and video equipment, before with the old breakers, and now with new ones.

The unit was tested OK at the repairman, was OK yesterday when I was finishing assembling it, was using headphones to listen to and sounded as perfect as always.

Since my phono cable is a little stiff, I need to connect it to the recivier BEFORE puting the TT back to the dedicated shelf, shelf I need to remove in order to reach the other components.

ONLY when all cables are plugged into the Marantz, I can reinstall the shelf (granite plate) and the TT.

Just hope to have explained the situation.

I think the Motorola transistor is dead, so where do I buy now equivalent transistors?
 
This is new territory for most people in the US to understand.

His house voltage is 220 Volts ,the unit is wired for 220 Volts.

Both wires in the line cord have 220 across them and each has 110 Volts in respect to ground.

Who knows if the power switch is properly wired breaking BOTH sides of the 220 when off and/or if somehow the chassis is "HOT" in relation to one side of the 220 wiring.

Bob
 
The power plug has 3 pins... if this add something, is not the usual 2 pins plug often used in Europe...
 
wlhd1610 said:
Both wires in the line cord have 220 across them and each has 110 Volts in respect to ground
Click to expand...
Wrong.
If two wires : one is zero, the other 230 VAC.
If three wires : one is zero, one is 230 VAC and the third is ground.
We have only ONE phase (for audio stuff anyway !)

Many Marantzes of that vintage I see here (Switzerland ) have a three pronged plug, and the chassis is connected to the ground.
 
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Regardless of your house wiring, You are usually best in replacing all the output transistors. I believe there will, most likely, be an OnSemi substitution for your cooked device. Someone more familiar than I will be able to help with that choice. The real problem will, as previously pointed out, be what happened back upstream from the output. Seldom does anything blow without dragging its problems into the rest of the system. Do a search for that Motorola transistor # and you may get your answer. I would go ahead and pull the rest of the outputs and test them all. Be sure to mark which one came from where and take pictures of them all before removing.

Can you tell us if there was a considerable explosion when this contact was made. What then happened to the phono? I am struggling, like the others, to understand how contact with a phono plug could cause so much disturbance. You realize that now you will have to open up the Marantz and have a look inside, for damage of any kind. Keep us informed and tell us more for clarity's sake. Pics would also be a good thing. Good luck to you.
 
Are you saying in Europe one side(prong)of your 220 outlet is "0" volts referenced to ground?

If so I stand corrected.

If so that is entirely different than our 220 here in the states which is 220 across both hots but each leg of our 220 is 110 volts in reference to ground (or neutral).
Single phase or 3 phase is not even a part of this conversation as that nomenclature just confuses the issue.

Disclaimer:
I have been a licensed commercial electrician for over 40 years.


Bob
 
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I'm sorry, I forgot to previosusly mention that I stupidly did all wrong, i.e. since I was planning to hook up the system, connect the loudspeakers in order to proceed with the tuning section fine dial setting, I was working with NO cover on it, power off but still connected to the electrical ring, with the heat sinks exposed.

I will never forgive myself for such foolish mistake.

Can anyone point me to the transistor correct part number? If I understand well the schematics, it should be the P700 board, am I right? But still unable to read and understand the original part number of the two dedicated transistors on the heat sink.

My Marantz worked really fine for 40 years, had troubles sometimes (broken power switch, noisy potentiometers, dead dial lamps), but in general gave me in the last 20 years with me, many and many hours of very fine music and audio quality.

It had been recapped and upgraded (new bigger power caps, general recapping, new and better relay) about 10 years ago, and it had a sound I loved so much...and because of all this I became a Marantz fan.
 
wlhd1610 said:
Are you saying in Europe one side(prong)of your 220 outlet is "0" volts referenced to ground?

If so I stand corrected.

If so that is entirely different than our 220 here in the states which is 220 across both hots but each leg of our 220 is 110 volts in reference to ground (or neutral).
Single phase or 3 phase is not even a part of this conversation as that nomenclature just confuses the issue.

Disclaimer:
I have been a licensed commercial electrician for over 40 years.


Bob
Click to expand...
In the US, while one leg is at +110(really 120+ now) the other is at -110. Meaning it has 220v 60 times per.

apparently in the third world heh heh ;-) one leg is stable earth and the other rotates +/- 200-something

sooooo, its a lot like what we have here where you can have neutral or hot on the chassis with a non polarized plug. I guess it would be possible to have one chassis hot, the other neutral and touch the wrong thing BUT, we tend to have a 2Mohm resistor on the chassis making it hot but not deadly.

to pop a breaker, current had to flow. To pop an AFCI, Or GFI, those kinds of faults have to be present, something needs checked out. and I bet the marantz needs a fresh tune up
 
wlhd1610 said:
Are you saying in Europe one side(prong)of your 220 outlet is "0" volts referenced to ground?
Click to expand...

Yes that is right. The standard voltage years ago was 220 for Europe and 240 for the UK, now the standard is 230.

quaddriver said:
In the US, while one leg is at +110(really 120+ now) the other is at -110. Meaning it has 220v 60 times per.
Click to expand...

But don't you have a "zero" leg as well ? And doesn't all the equipment we are talking about use only one 120V leg and "zero" ?

Sorry @dario54 this has become much about mains voltages :confused: I hope you find where your problem is.
 
Bert 1100 said:
Yes that is right. The standard voltage years ago was 220 for Europe and 240 for the UK, now the standard is 230.



But don't you have a "zero" leg as well ? And doesn't all the equipment we are talking about use only one 120V leg and "zero" ?

Sorry @dario54 this has become much about mains voltages :confused: I hope you find where your problem is.
Click to expand...
in a single phase house we get 3 wires from the pole. hot hot and a neutral/ground. when we build power plants we excavate 100's of acres and bury this insanely thick copper mesh in the earth (or next to water) and sent the hots. every junction, pole, xformer whatever has a lead to earth. The at the house pole the service box (be it on *a* pole or in the building has bussbars that create 2 lines, neutral and ground. From that point on, we send 3 wires to every light,recep junction - hot, neutral and ground and if we have a sub panel we send 4 wires, hot, hot neutral and ground and we keep neutral and ground physically separate all the way back to the box to avoid problems should someones circ saw go batshit.
 
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