Marantz PM17 Repair

[tvi]

check d715,716

 

[solan]

Comprobados, están Ok

 

[solan]

check d715,716

Checked, they are Ok

 

[jaycee]

Check the voltages at the emitters of Q711 and Q712, referenced to ground. You should see about 1.2v there. If not, it is likely Q702 has died - though you can also then check R729/R730 are OK

Actually, were drivers Q713 and Q714 damaged ? If they were damaged, check Q711/Q712 and all of the connecting resistors.

 

[solan]

. Q713, Q702 and Q714 were not damaged, but just in case for the tests I'm using the good channel transistors. Tomorrow I will check the voltages at the emitters Q711 and Q712.
An observation: when I turn on only the good channel, the source selection LED works, when I turn on only the bad channel, the source selection LED does not work. Thank you for your patience

 

[solan]

The voltages at the emitters of Q711 and Q712 is: 0,98 V and 0,99V, Remember, I've done the readings with the light bulb. It's okay?

 

[solan]

These are the readings I've done:

Service Manual Readings
-Q712, Q711----------1.2V---------------0,90V (emisor)
-Q713, Q714----------0.65V------------- 0,394V (emisor)
-Q715, Q716----------42,6v--------------38,56V (colector)
-Q715, Q716--------0,026-0,036V--------0,005-0,006V (emitter)

The readings are low, are we doing well?

 

[solan]

It works the BIAS !!!, R727 (2.2K) variable was wrong, waiting for the transistors 2SC3519 / 2SA1386. When they arrive and try without the bulb I will continue counting. Thank you very much

 

[solan]

Hello, the bad channel worked, no bulb and audio signal !!!, but I received the transistors 2SC3519 / 2SA1386 and now the good channel does not work because it has the old small transistors of the channel that exploded. So I have to replace: "SC3419-2SC4793 / 2SA1837" and the work will be finished.
I have read about replacements for these transistors but I am very confused. What can be good replacements for ?:
-2SC3419 and
-2SC3519 / 2SA1386
Thank you very much.

 

[solan]

Hi, I'm sad and tired, I bought Profusion 2SC3519 / 2SA1386 and everything was perfect. I tried my luck in a Spanish store with SC3419-2SC4793 / 2SA1837 but when I went up the bias or a bit the volume with audio ... boom the bulb turned on and there was a short circuit. I have verified with certainty that they are bad or they are false.
Please, what replacements are for ?:

- 2SC3419-Y (It has to be only with the letter Y)
Characteristics of the 2SC3419-Y bipolar transistor

Type - n-p-n
Collector-Emitter Voltage: 40 V
Collector-Base Voltage: 40 V
Emitter-Base Voltage: 5 V
Collector Current: 0.8 A
Collector Dissipation - 5 W
DC Current Gain (hfe) - 120 to 240
Transition Frequency - 100 MHz
Operating and Storage Junction Temperature Range -55 to +150 ° C
Package - TO-126F

2SC4793 / 2SA1837 (It can be Y or it can be O) Bipolar Transistor
Characteristics of the 2SC4793 bipolar transistor

Type - n-p-n
Collector-Emitter Voltage: 230 V
Collector-Base Voltage: 230 V
Emitter-Base Voltage: 5 V
Collector Current: 1 A
Collector Dissipation - 20 W
DC Current Gain (hfe) - 100 to 320
Transition Frequency - 70 MHz
Operating and Storage Junction Temperature Range -55 to +150 ° C
Package - TO-220F.

Thank you very much. Now I will not bother you anymore.

 

[solan]

Hi, I'm sad and tired, I bought Profusion 2SC3519 / 2SA1386 and everything was perfect. I tried my luck in a Spanish store with SC3419-2SC4793 / 2SA1837 but when I went up the bias or a bit the volume with audio ... boom the bulb turned on and there was a short circuit. I have verified with certainty that they are bad or they are false.
Please, what replacements are for ?:

- 2SC3419-Y (It has to be only with the letter Y)
Characteristics of the 2SC3419-Y bipolar transistor

Type - n-p-n
Collector-Emitter Voltage: 40 V
Collector-Base Voltage: 40 V
Emitter-Base Voltage: 5 V
Collector Current: 0.8 A
Collector Dissipation - 5 W
DC Current Gain (hfe) - 120 to 240
Transition Frequency - 100 MHz
Operating and Storage Junction Temperature Range -55 to +150 ° C
Package - TO-126F

2SC4793 / 2SA1837 (It can be Y or it can be O) Bipolar Transistor
Characteristics of the 2SC4793 bipolar transistor

Type - n-p-n
Collector-Emitter Voltage: 230 V
Collector-Base Voltage: 230 V
Emitter-Base Voltage: 5 V
Collector Current: 1 A
Collector Dissipation - 20 W
DC Current Gain (hfe) - 100 to 320
Transition Frequency - 70 MHz
Operating and Storage Junction Temperature Range -55 to +150 ° C
Package - TO-220F.

Thank you very much. Now I will not bother anymore.

 

[solan]

No one?

 

[solan]

I had not seen that in Profusion they have replacement for SC3419 and 2SC4793 / 2SA1837. Today I made the order:

2SC4793LB-TF3T - Power Transistor 230V 1A
2SA1837LB-TF3T - Power Transistor -230V -1A
BD139-16 - Power Transistor 80V 1.5A

The brand is UTC (Unisonic), hopefully luck

 

[jaycee]

Profusion sell good quality parts. It is likely the other store you mentioned sold you fake parts, and that is why they failed

 

[solan]

Hi, the Profusion transistors have arrived. I have tried with the bulb and I have adjusted the Offset and the Bias and after I have put audio signal at low volume, everything is perfect !!!!. But now the real test comes, plug without the bulb. Any suggestions before doing this ?, Thanks.

 

[solan]

A week working properly !!!!!🙂🙂🙂🙂🙂

In case it serves someone with a Marantz PM17 these are good replacement transistors:
2SC3284/2SA1303(sanken)------2SC3519/2SA1386 (sanken)
2SC4793/2SA1837 (toshiba)-----2SC4793LB-TF3T /2SA1837LB-TF3T (Unisonic)
2SC3419Y-------------------------BD139-16 (Unisonic).

Profusion/UK

Thanks to everyone and to this forum for the help.