To me there are differencies. See picsIsn't it using the same power supply configuration ( 2200uf ) with the same O/P caps ( 1500 uf ) with the same drivers ( 2Sc1030 )?
What is the difference ?
There are two transistorsMany thanks Stene - I have looked at board F1248 and there is a transistor - TR704 - thank reacts to freeze spray and the background noise drops of dramatically. I am presuming this is the board associated with the tone control - its attached to the volume/ balance/bass/treble controls. The transistor is marked C458 4H. Also, what polarity should I be looking for - NPN or PNP?
cheers once again Stene - finally feel as if its possible to raise this phoenix from the ashes!:thmbsp:
ExperienceWOW that's troubleshooting !
:thmbsp:Stene !
How did you find problem was this precise transistor ?
No I don't have everything, sorryYou have everything ?
All Sansui schematics ?
Others ? Like Kenwood KA 4006 ?
There are two transistors
on the board. C458 = 2SC458 it's a NPN. Replace both. A transistor like 2SAxxx = PNP
Comparing old with modern ? The best method is by their specsStene
Can you recommend a method of comparing old transistors with modern replacements - is there some holy grail like guide that shows suitable contemporary transistors, possibly online??
J
I'm not fond of NTE as you never know what you get. It can be good but also bad because NTE isn't a manufacturer of transistors. They are buying large quantities from different companies and rename them to NTExxxx. Some DMM has a hFE mode other µF mode.I use NTE cross reference #s. They usually works. But you need to verify as I was misleaded sometimes like NTE # 123A and 123AP has same specs but different pin out... Very bad to use wrong pin out. And you don't suspect this transistor as you just replaced it... When you have corespondent, you can also check the HFE using a multimeter. You can match pairs this way too.
Do you agree Stene ?
Hm :scratch2: So in this case the transistor is 2SC458 and you get the NTE cross ref number which is NTE85.I usually get the NTE cross ref. number and buy a transistor with the same number at the electronic surplus store around which buys good and not so good transistors. I can then decide which one I want. I never bought NTE brand transistors.
I always replace those nasty little filament lamps in the pointer with a miniature LED. If fed by AC you MUST bypass the LED with a reverse connected Si junction diode to take the reverse 1/2 cycle voltage (this goes for all LED's - they have a very low tolerance to reverse voltage.)Hey that's a good haul!
What I am after is the schematics for the the 350A - want to try and give it the once over plus find a replacement for the 'needle ' bulb on the tuning display.
Any info you have would be cool
Cheers
J
There are two transistors
on the board. C458 = 2SC458 it's a NPN. Replace both. A transistor like 2SAxxx = PNP
Well you're not getting the 350A back Mr. Onkyo! But I'm glad you're enjoying the 4000. I'll have to come down to hear the 4000 with your setup.Wow, that's really quite a coincidence since I just picked up beautiful Sansui 4000 from a co-worker of mine, all he wanted was my 350a. I can't tell you how happy I am with the 4000, but I do miss that little 350a. :thmbsp: