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semi transister need a cross-reference if possible

rbrumsboo's picture


semi transister need a cross-reference if possible

this came from a VISONIC stereo amplifier 2 channel model NA-4300




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rbrumsboo's picture

Re: semi transister need a cross-reference if possible

as it turns out this unit is actually a H.H. SCOTT courtesy mknovak the two units are identical as you can see for yourself at http://prntscr.com/f84rjm and http://prntscr.com/f84sol so now we have the correct specs to get this unit up and running again. thanks again mknovak for all your help.

mknovak's picture

Re: semi transister need a cross-reference if possible

You may use 2N3055, it's more powerful n-p-n transistor (Pc=115W, Ic max=15A, Ucb max=60V, TO-3 case), than 2SD428 (Pc=60W, Ic max=7A).
It's complementary transistor is MJ2955 (p-n-p) (Pc=115W, Ic max=15A, the same TO-3 case).
It's more powerful and reliable pair of transistors for power output stage.
Mknovak

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

ok thank you for that info. maybe you can help me with my next problem as well? see the burned up resister it is a dark red how do i order a new one of those with that background color? i can pretty much make out the color bands but never seen a Carbon Composition Resistors like that before? http://prntscr.com/elvymv

mknovak's picture

Re: semi transister need a cross-reference if possible

In my opinion there are low power (~0,5...1W) wirewound resistors. I can't exactly detect the colors of the 1-st (orange? means "3") and 3-rd marking bands (maybe golden, that means x0.1 multiplying factor), so I think that the burned up resistor is 3.9 Ohm 5% 1W wirewound. The resistor at the right part of the photo is a similar one.
Mknovak

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

1 more question for you i did order the 2 nte328 transistors but seems i did not order there complementary transistor. do you recall what they are?

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

how come the Koreans use transistors that all are identical? example http://prntscr.com/faiikm they all have the same info printed on them. wouldn't that be confusing when assembling?

Re: semi transister need a cross-reference if possible

They are identical because they all do the same thing, with the same specs and requirements.
Do you want your car to have four different tires because they go on different locations on your car?

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

and what about NPN and PNP if they are identical....?

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

if that is the case why do we use combination transistors example 2N3055 & MJ2955 we want small tires in the front and big fat ones in the rear?

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

Novak are you on a holiday? if so, i am sorry, did not mean to bug ya. i can wait till you return. i have been sitting on this amp for 4 months already so a week or two wont be that bad. i will check back daily.... have fun!!!

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

I just thought of another question, when placing the semi transistors in place witch sequence should i use 1) MJ2955~2N3055 MJ2955~2N3055 or 2) 2N3055~MJ2955 2N3055~MJ2955 or 3) 2N3055~2N3055 MJ2955~MJ2955 or 4) MJ2955~MJ2955 2N3055~2N3055 ? remember the only writing on the old ones is the ".T D428 0 7H" and thats on all 4 of them.

rbrumsboo's picture

Re: semi transister need a cross-reference if possibleonn

Novak. gonna start the repair this week. hope it goes well. thought i should thank you again for all your council. i sincerely appreciate your help, and by the way....nice pic. R. Brums

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

there is one by the blue Capacitor is that the one you mean? the colors are orange white red and gold that = 3.9 ohms +5%. these seem to be carbon composition resistors i was reading about them yesterday. made from clay. here is a link to that [http://www.resistorguide.com/carbon-composition-resistor/] if these are carbon composition resistors do you know of a good replacement that wont throw everything else out of wack?

rbrumsboo's picture

Re: semi transister need a cross-reference if possible

HERE IS WHAT YOU ARE LOOKING AT " LINE 1= .T LINE 2= D 428 LINE 3= 0 7H"

Re: semi transister need a cross-reference if possible

That transistor is a 2SD428...
NTE offers a replacement, their part number is NTE328.
I use their substitutes all the time.
You can buy them from MCM on line, or eBay
Frank