California Electronics pro-8800a digital amplifier stereo

[petehall347]

what is getting hot ?
looking at the pics i see what might be a burned capacitor next to a driver transistor .
have you measured dc voltages at the speaker outs ? and also the voltages across the low ohm emitter resistors next to the outputs ?

[labello]

what is getting hot ?
looking at the pics i see what might be a burned capacitor next to a driver transistor .
have you measured dc voltages at the speaker outs ? and also the voltages across the low ohm emitter resistors next to the outputs ?

Hi, thanks for the reply, the resistor that I marked with arrow yellow, then I changed both transistor red colour but nothing changed (also I changed also that resistor still getting hot about 100/150 degrees. No i didn't take measurements, I just go ahead with testing transistor mosfet on the heatsink...

[labello]

what is getting hot ?
looking at the pics i see what might be a burned capacitor next to a driver transistor .
have you measured dc voltages at the speaker outs ? and also the voltages across the low ohm emitter resistors next to the outputs ?

Hold on you just know Where's the problem?( i see what might be a burned capacitor next to a driver transistor) how can you know that through a picture ..? Really...

[petehall347]

Hold on you just know Where's the problem?( i see what might be a burned capacitor next to a driver transistor) how can you know that through a picture ..? Really...

this one here .. and what is that silvery mess in the other pic ?

[R_J]

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[labello]

.

?

[labello]

this one here .. and what is that silvery mess in the other pic ?

Hi don't worry it's just dirty, anyway thanks for the reply, I found those cable almost broken then I resolder them, but in one side the resistor doesn't getting hot anymore, then in the other side blown up another resistor and two transistor in the heatsink circled red on picture, now they are different, 2 marks on it TOSHIBA 2SA1943 and the others are TOSHIBA 2SC500 . Can I replaced all whit the same mark or i must replaced different like they are now? Thanks for the reply 👍

[petehall347]

yes replace with same . also be sure the bias tracking tracking transistors are good .

[labello]

yes replace with same . also be sure the bias tracking tracking transistors are good .

So both mark are the same right? Thanks

[petehall347]

So both mark are the same right? Thanks

same as what is there . they are pairs of npn pnp one of each for each channel .

[labello]

same as what is there . they are pairs of npn pnp one of each for each channel .

Understand, I'll buying and we'll see how's it goes. Thanks for the reply and happy new year to all 👍🙏

[labello]

Hi guys, what about those resistor they have similar mark on the board but as you can see the similar is different... is strange isn't Thank you

[labello]

Hi guys i replaced those components on the heatsink and the resistor that blown up. So I test it with phone to read input and it works but I can't slow down the volume on the front pannel, so I check the board and the same resistor going almost 80/90 degrees ... it's normal? Before was really hot 150 degrees.. thanks to all for the reply

[labello]

what is getting hot ?
looking at the pics i see what might be a burned capacitor next to a driver transistor .
have you measured dc voltages at the speaker outs ? and also the voltages across the low ohm emitter resistors next to the outputs ?

Hi I'm sorry for the late, anyway I measured in the back side I don't have any voltages ,then in the input side I have a very high ohm. . You can see on pictures here. And thanks to all for the reply 🙏 I really hope we can fix this amplifier it's a nightmare 🙄

[labello]

this one here .. and what is that silvery mess in the other pic ?

Hi i already changed the pico capacitor, I changed all of them. But stil it doesn't work that resistor still getting HOT as you can see on the picture . Honestly guys I don't know what I should do. 😔 thanks to all

[petehall347]

Hi i already changed the pico capacitor, I changed all of them. But stil it doesn't work that resistor still getting HOT as you can see on the picture . Honestly guys I don't know what I should do. 😔 thanks to all

what does the datasheet say for the resistor ? you can calculate the current by measuring the voltage right across it

[labello]

what does the datasheet say for the resistor ? you can calculate the current by measuring the voltage right across it

Hi thanks a lot for the reply, the voltage is about 8 voltage. The datasheet don't tells me anything about voltage only the ohms

[petehall347]

Hi thanks a lot for the reply, the voltage is about 8 voltage. The datasheet don't tells me anything about voltage only the ohms

that is not the datasheet

[labello]

that is not the datasheet

You mean datasheet of the board? I didn't find it 😔

[petehall347]

You mean datasheet of the board? I didn't find it 😔

no the resistor
anyway 8v across 91 ohms is 0.7032967 watts