Plomaman27
SparkJockey
Greetings from a newbee! I just picked up a Sansui G-7500 but it has blown driver and power amps on the left speaker circuit. Can anyone out there suggest where to buy replacement transistors for these beasts?:scratch2:
Sansui "G" power amps...where to find?
- Thread starter Plomaman27
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kevzep
Its all about the Music
What you should do is keep everything related to your repair in the one thread....eggs in the same basket etc etc.....
Onsemi have these the out transistors you need for the output stage, as well as the transistors for the drivers.....
2SC2581 = NJW3281G (NPN) TO-3P casing (output transistor)
2SA1106 = NJW1302G (PNP) TO-3P casing (output transistor)
2SD381 = MJE15030 (NPN) TO-220 casing (driver transistor)
2SB536 = MJE15031 (PNP) TO-220 casing (driver transistor)
Heres some links......buy a few spares......that way if you have another meltdown you will have spares...
http://www.onsemi.com/PowerSolutions/product.do?id=NJW1302
http://www.onsemi.com/PowerSolutions/product.do?id=MJE15030
http://www.onsemi.com/PowerSolutions/product.do?id=MJE15031
The G variants are OK, the G just means they are "lead free".......
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Plomaman27
SparkJockey
Fantastic kevzep... Much appreciated for sure! Now its time to order and get this unit repaired.
Stene
The Introducer
Typo. 2SA1106 PNP TO-3P complementary 2SC2581 NPN
kevzep
Its all about the Music
Thanks Stene, I missed that one......Cheers...:thmbsp:
Plomaman27
SparkJockey
Thanks guys
I got my hands on a pdf schematic for my G-7500 and it lists the following:
(L-CH)
TR601 2SA1106NLB O, Y
TR602 2SC2581NLB O, Y
(R-CH)
TR602 2SA1106NLB O, Y
TR601 2SC2581NLB O, Y
Not sure what the O and Y are....
Im assuming that each PA complementary pair operates right or left output. Are TR601 and TR602 the same except for polarity?
kevzep yesterday you asked if the DC supply caps were shorted to ground... were you referring to C704 and C705 the two 10Kuf electrolytics? Well, C705 (-) and C704 (+) are normally tied to ground but the other sides of both caps do show charging action on the DMM.
BTW, I found the correct procedure for removing the PA's from the G-7500.
It is as follows:
1. Remove top bonnet
2. Remove bottom plate
3. loosen screws and then slide rear panel upwards
4. loosen screws securing circuit board F-2981 to heat sink
5. Remove power transistor from circuit board F-2981
Phew! What a relief to know I wont have to remove the whole back panel. This repair is looking easier and easier the more I look into it.
The one thing Im still not too sure about is the Dim Bulb Tester. How do I build one and how would I use it?:scratch2:
I got my hands on a pdf schematic for my G-7500 and it lists the following:(L-CH)
TR601 2SA1106NLB O, Y
TR602 2SC2581NLB O, Y
(R-CH)
TR602 2SA1106NLB O, Y
TR601 2SC2581NLB O, Y
Not sure what the O and Y are....
Im assuming that each PA complementary pair operates right or left output. Are TR601 and TR602 the same except for polarity?
kevzep yesterday you asked if the DC supply caps were shorted to ground... were you referring to C704 and C705 the two 10Kuf electrolytics? Well, C705 (-) and C704 (+) are normally tied to ground but the other sides of both caps do show charging action on the DMM.
BTW, I found the correct procedure for removing the PA's from the G-7500.
It is as follows:1. Remove top bonnet
2. Remove bottom plate
3. loosen screws and then slide rear panel upwards
4. loosen screws securing circuit board F-2981 to heat sink
5. Remove power transistor from circuit board F-2981
Phew! What a relief to know I wont have to remove the whole back panel. This repair is looking easier and easier the more I look into it.
The one thing Im still not too sure about is the Dim Bulb Tester. How do I build one and how would I use it?:scratch2:
kevzep
Its all about the Music
You dont need to worry about O and the Y apart from curiosity, we have the substitutes sorted.......
They may be in relation to hfe, voltage, ft, those sorts of variant's between the transistors available in the same line.......
Yes 601 and 602 are known as complimentary pairs, they are the same apart from the polarity......
What I was getting at was to check for a dead short in the supply other than the dead short that the transistors were causing.....Just to double check nothing else was causing a problem....
Yes the DMM will charge the capacitor up, but if there is a dead short, you would see it immediately....
The DBT (dim bulb tester) just google it on AK... What happens is the bulb is in series with the incoming mains so that if there is a short circuit in the amplifier the light bulb will light up instead of frying the amplifier....Its acting as a current limiter basically......
yes indeed always good to get the service manual.....