I have some questions regarding what power transistors to use and how clearly they need to be matched.
One of the power resistors on the right side shorted and took the other one out. The R42 100 ohm resistor between them also burnt up.
I bought 4 each On Semi
MJ21193G and 94G to replace them based on a thread I read here a while back.
The hfe for the new 93G PNP ones is around 80 while the NPNs are 55. Should they match closer?
Also the original ones had hfes around 150. Should the news ones be closer to that value?
Are there different ones I should be using?
intuitively I think the new ones should match alot closer and have a higher gain but I thought I’d ask.
Also, the R42 resistor and pretty much all the small resistors are 1/2w while the schematic calls for 1/4w for it and all others. I was going to go back with 1/2w but it would seem 1/4w would be better since it acts like a fuse. Based on the 0.5v voltage drop on the schematic the normal wattage should be v2/r = 0.0025 or 100x less than 1/4w. ??
Thanks!
One of the power resistors on the right side shorted and took the other one out. The R42 100 ohm resistor between them also burnt up.
I bought 4 each On Semi
MJ21193G and 94G to replace them based on a thread I read here a while back.
The hfe for the new 93G PNP ones is around 80 while the NPNs are 55. Should they match closer?
Also the original ones had hfes around 150. Should the news ones be closer to that value?
Are there different ones I should be using?
intuitively I think the new ones should match alot closer and have a higher gain but I thought I’d ask.
Also, the R42 resistor and pretty much all the small resistors are 1/2w while the schematic calls for 1/4w for it and all others. I was going to go back with 1/2w but it would seem 1/4w would be better since it acts like a fuse. Based on the 0.5v voltage drop on the schematic the normal wattage should be v2/r = 0.0025 or 100x less than 1/4w. ??
Thanks!
