hi
i have replaced TIP35/36C blow out put stage trasistors from Focal amp and replaced with 2SC5200 pairs.
Now there is a REFERENCE POINT and BIAS CHECK point. The voltage across all four channels is 2mV to 80 mv.
VCE= 30.6 volt for all
VBE= 0.35V to 0.55 Volt ?
Any guidance how to adjust bias before i blow them out again.😕
i have replaced TIP35/36C blow out put stage trasistors from Focal amp and replaced with 2SC5200 pairs.
Now there is a REFERENCE POINT and BIAS CHECK point. The voltage across all four channels is 2mV to 80 mv.
VCE= 30.6 volt for all
VBE= 0.35V to 0.55 Volt ?
Any guidance how to adjust bias before i blow them out again.😕
No. Actually its second replacement, the yesterday replacement were all well before i put a bridged load on it.
so yes i am asking before powering it up before second time. But i am using series bulbs with the power supply just in case.🙂
so yes i am asking before powering it up before second time. But i am using series bulbs with the power supply just in case.🙂
TIP 35 is an NPN whereas TIP36 is PNP inferring a complementary pair. 2SC5200 is NPN, It would suggest to me that you need a PNP to match the replacement of the TIP36.The correct complement for the 2SC5200 is a 2SA1943
Cheers / Chris
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just forgot to mention though in my earlier post. yes indeed it 2SA5200 was matched with 2SA1943, and tried to match within 5% of VBe, not sure of hFE though.
Biasing ? VBE ? HELP?
Biasing ? VBE ? HELP?
OK, so there is not a fault to trace unless the output transistors took something else with them when they died.
Hi, Nigel,
nice to see confirmation.
Any chance you could go over and explain that to the other Members that cannot or will not grasp that.
I gave up trying different explanations of why their closed in thinking was wrong.
nice to see confirmation.
Any chance you could go over and explain that to the other Members that cannot or will not grasp that.
I gave up trying different explanations of why their closed in thinking was wrong.
nigel my question is not about the load in bridge load its about biasing after changing the out put transistors.
I dont think anything else is destroyed as i powered up the amp through a series bulb resistor, it has turned on and with small signal input all the channels are working fine without much current draw to indicate a shortage or overheating,
But how do i check whats the ideal bias current ? at what value should i adjust the bias pots. ?
I dont think anything else is destroyed as i powered up the amp through a series bulb resistor, it has turned on and with small signal input all the channels are working fine without much current draw to indicate a shortage or overheating,
But how do i check whats the ideal bias current ? at what value should i adjust the bias pots. ?
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