stereoguy70
Well-Known Member
Ok, so like the title says....another question as I'm new to the Sansui fold.......
A little back story first. I recently was given this 4000 from a guy I work with who was cleaning out his brother's estate. His late brother was the original owner of this fantastic piece of audio artwork. Anyway, sometime in its past the right channel had a minor meltdown on the power amp side of things. Seems that resistor R829 (100ohm) fried and the 2sa537 transistor got taken out, as well as both 2sc213 output transistors on that channel. I found the "repair" to this failure when cleaning out the years of dust from the inside of it. Well, whoever did the repair did some transistor substitutions......they used a sylvania egc129 as a replacement for the 2sa537, and two sylvania ecg128's for the output transistors and a rather sorry looking carbon comp 100ohm resistor to replace R829, but they soldered it to the BACK of the board rather than on the front of the board where the original one was! I also found an 8amp fuse in the main power supply fuse holder (supposed to be a 5amp for 117v...I'm in the USA so....) and I found two 5amp 32v fuses in the speaker output fuse holders where there should have been 3.5amp fuses!
I also found that the ecg129 transistor was barely soldered into the power amp board! Hence the crackling noise I was chasing too.......anyway, my plan is to replace the ecg129 with the proper 2sa537 (NOS of course) and the two ecg128's with the proper 2sd213 sankens (also NOS....not an easy find as it turns out, but I found them) and putting the proper 5amp fuse in the power supply fuse holder.
Now here comes the question.......(sorry for the long rambling backstory but I thought it pertinent to the question).......I can only seem to find 3amp fast acting fuses locally, not the recommended 3.5amp fuses for the speaker protection fuses. Can I get away with 3amp fuses in place of the 3.5amp that is recommended, or will they blow fairly quickly? I wouldn't think that 1/2 an amp lower would be that big of a change, but maybe it is.
I'm figuring by replacing those "close enough" transistors with the proper numbers and then resetting the bias, etc. It should be closer to the proper specs than it is now. BTW, I have already repaired the bogus resistor "repair" with the proper 100ohm carbon film 1/4 watt fuse and on the correct side of the board as well!
So, I guess I'm asking if 3amp is going to work even though it will be a "close enough" repair......
A little back story first. I recently was given this 4000 from a guy I work with who was cleaning out his brother's estate. His late brother was the original owner of this fantastic piece of audio artwork. Anyway, sometime in its past the right channel had a minor meltdown on the power amp side of things. Seems that resistor R829 (100ohm) fried and the 2sa537 transistor got taken out, as well as both 2sc213 output transistors on that channel. I found the "repair" to this failure when cleaning out the years of dust from the inside of it. Well, whoever did the repair did some transistor substitutions......they used a sylvania egc129 as a replacement for the 2sa537, and two sylvania ecg128's for the output transistors and a rather sorry looking carbon comp 100ohm resistor to replace R829, but they soldered it to the BACK of the board rather than on the front of the board where the original one was! I also found an 8amp fuse in the main power supply fuse holder (supposed to be a 5amp for 117v...I'm in the USA so....) and I found two 5amp 32v fuses in the speaker output fuse holders where there should have been 3.5amp fuses!
I also found that the ecg129 transistor was barely soldered into the power amp board! Hence the crackling noise I was chasing too.......anyway, my plan is to replace the ecg129 with the proper 2sa537 (NOS of course) and the two ecg128's with the proper 2sd213 sankens (also NOS....not an easy find as it turns out, but I found them) and putting the proper 5amp fuse in the power supply fuse holder.
Now here comes the question.......(sorry for the long rambling backstory but I thought it pertinent to the question).......I can only seem to find 3amp fast acting fuses locally, not the recommended 3.5amp fuses for the speaker protection fuses. Can I get away with 3amp fuses in place of the 3.5amp that is recommended, or will they blow fairly quickly? I wouldn't think that 1/2 an amp lower would be that big of a change, but maybe it is.
I'm figuring by replacing those "close enough" transistors with the proper numbers and then resetting the bias, etc. It should be closer to the proper specs than it is now. BTW, I have already repaired the bogus resistor "repair" with the proper 100ohm carbon film 1/4 watt fuse and on the correct side of the board as well!
So, I guess I'm asking if 3amp is going to work even though it will be a "close enough" repair......
