Replace Transistor Question
- Thread starter BWareLOUD
- Start date
Deceptively simple question. Fraught with future danger. I can infer a lot from the question.
answer: sort of. speed is important, and collector to base capacitance can tame things some, but...
you have a lot of problematic transistors in the unit. 2sa725, 2sa726 and 2sc14151
being new, have you lurked enough to have found the voluminous parts lists? have you read this forum much?
it isn't enie menie minie moe, Pioneer even compromised in places and a DOUBLE compromise without reverse engineering the circuit to figure out what's important can result in problems when choosing substitutes...
find the parts lists, familiarize with format, make your own list, basing list of what's in the BOM.
then I will find similar circuits in other models with similar characteristics that I have already reverse engineered
and modify the list with their subs.
I don't have enough time to make the initial list, do the research and make substitutions.
here's a teaser,
AWM-072
q5 2sc869 > 512-KSC1845FTA
q6 2sc869 > 512-KSC1845FTA
q7 2sc945 > 512-KSC1845FTA
q8 2sc945 > 512-KSC1845FTA
q9 2sa733 > 512-KSA992FBU
q10 2sc945 > 512-KSC2383YTA
q11 2sc1384 > 512-KSC2690AYS
2sa725 > 512-KSA992FBU
2sa726 > 512-KSA992FBU
2sc1451 > 512-KSC3503DS
2sc1312 > 512-KSC1845FTA
2sc1313 > 512-KSC1845FTA
I see no problems across the sa-7500 substitutions above.
I don't have the power supply stuff yet.
answer: sort of. speed is important, and collector to base capacitance can tame things some, but...
you have a lot of problematic transistors in the unit. 2sa725, 2sa726 and 2sc14151
being new, have you lurked enough to have found the voluminous parts lists? have you read this forum much?
it isn't enie menie minie moe, Pioneer even compromised in places and a DOUBLE compromise without reverse engineering the circuit to figure out what's important can result in problems when choosing substitutes...
find the parts lists, familiarize with format, make your own list, basing list of what's in the BOM.
then I will find similar circuits in other models with similar characteristics that I have already reverse engineered
and modify the list with their subs.
I don't have enough time to make the initial list, do the research and make substitutions.
here's a teaser,
AWM-072
q5 2sc869 > 512-KSC1845FTA
q6 2sc869 > 512-KSC1845FTA
q7 2sc945 > 512-KSC1845FTA
q8 2sc945 > 512-KSC1845FTA
q9 2sa733 > 512-KSA992FBU
q10 2sc945 > 512-KSC2383YTA
q11 2sc1384 > 512-KSC2690AYS
2sa725 > 512-KSA992FBU
2sa726 > 512-KSA992FBU
2sc1451 > 512-KSC3503DS
2sc1312 > 512-KSC1845FTA
2sc1313 > 512-KSC1845FTA
I see no problems across the sa-7500 substitutions above.
I don't have the power supply stuff yet.
Thank you very much for your response,
I am led to believe the issue is with a transistor in the power supply circuit causing the relay to not kick in. Does that sound accurate?
I have got a service manual for the 7500, which I have used to identify original transistor models. I dont quite understand how to go about finding the replacements, nothing seems to match exactly on digikey etc.
I am led to believe the issue is with a transistor in the power supply circuit causing the relay to not kick in. Does that sound accurate?
I have got a service manual for the 7500, which I have used to identify original transistor models. I dont quite understand how to go about finding the replacements, nothing seems to match exactly on digikey etc.
Maybe, if the power supply voltages are not correct. Could be something else as well. Measure them and post your results, if you need assistance as to possible suspects.
512-KSC1845FTA is a Mouser part number, so just search Digi-Key for KSC1845FTA and you come up with KSC1845FTACT-ND
BTW, there is a direct sub for NEC 2sc945, Fairchild ksc945c, which is 100mA Ic rated vs ksc1845 50mA rated. Depending on the place used, a ksc1845 can be used if that is what you have on had.
