Quality 2SD424 transistor source? - UK Vintage Radio Repair and Restoration Discussion Forum

mole42uk · 12th Dec 2019, 12:37 pm

Hi,
I'm repairing a few Rogers AM8/16 (Quad 405-2) amplifiers. I need to buy some 2SD424 output transistors. Does anyone know a source of reputable components?

Top Cap · 12th Dec 2019, 1:15 pm

I recently repaired one and fitted MJ15003, recognised as a good suitable substitute.
Bought mine from Cricklewood :-
https://www.cricklewoodelectronics.com/MJ15003.html

Here is a link to the fun and games I had with a 405-2.
http://www.g4cnh.com/public/A_Quad_405_repair.pdf

paulsherwin · 12th Dec 2019, 3:37 pm

You are right to be cautious. There seem to be lots of fake 2SD424s around. I agree with TC, it would be safer to fit a current production equivalent if possible.

Craig Sawyers · 13th Dec 2019, 9:48 am

Quote:

Originally Posted by Top Cap

I recently repaired one and fitted MJ15003, recognised as a good suitable substitute.
Bought mine from Cricklewood :-
https://www.cricklewoodelectronics.com/MJ15003.html

Here is a link to the fun and games I had with a 405-2.
http://www.g4cnh.com/public/A_Quad_405_repair.pdf

Good write up! The only thing I would have done different is to mount the replacement for the red ERO capacitor that had been cooked by the power resistors, on the other side of the board. So well away from the source of heat.

Note this only happens for one channel. The other channel has that capacitor at the bottom of the board well away from heat.

I'll avoid the soapbox about Quad's brain-dead moment regarding the crowbar. I've waxed more than lyrical on other threads on this forum regarding that.

Craig

mole42uk · 13th Dec 2019, 2:02 pm

Thanks! I'll take that on board and fit a couple of MJ15003.

mole42uk · 13th Dec 2019, 3:50 pm

I did find some ON ones at RS - much cheaper than Cricklewood.

12th Dec 2019, 12:37 pm	#1
mole42uk Nonode Join Date: Aug 2010 Location: Resolven, Wales; and Bristol, England Posts: 2,612	Quality 2SD424 transistor source? Hi, I'm repairing a few Rogers AM8/16 (Quad 405-2) amplifiers. I need to buy some 2SD424 output transistors. Does anyone know a source of reputable components? __________________ Richard Index: recursive loop: see recursive loop

12th Dec 2019, 1:15 pm	#2
Top Cap Octode Join Date: Mar 2006 Location: Watford, Hertfordshire, UK. Posts: 1,270	Re: Quality 2SD424 transistor source? I recently repaired one and fitted MJ15003, recognised as a good suitable substitute. Bought mine from Cricklewood :- https://www.cricklewoodelectronics.com/MJ15003.html Here is a link to the fun and games I had with a 405-2. http://www.g4cnh.com/public/A_Quad_405_repair.pdf __________________ Whether the Top Cap is Grid or Anode - touching it will give you a buzz either way! Last edited by Top Cap; 12th Dec 2019 at 1:34 pm.

12th Dec 2019, 3:37 pm	#3
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Quality 2SD424 transistor source? You are right to be cautious. There seem to be lots of fake 2SD424s around. I agree with TC, it would be safer to fit a current production equivalent if possible.

13th Dec 2019, 2:02 pm	#5
mole42uk Nonode Join Date: Aug 2010 Location: Resolven, Wales; and Bristol, England Posts: 2,612	Re: Quality 2SD424 transistor source? Thanks! I'll take that on board and fit a couple of MJ15003. __________________ Richard Index: recursive loop: see recursive loop

13th Dec 2019, 3:50 pm	#6
mole42uk Nonode Join Date: Aug 2010 Location: Resolven, Wales; and Bristol, England Posts: 2,612	Re: Quality 2SD424 transistor source? I did find some ON ones at RS - much cheaper than Cricklewood. __________________ Richard Index: recursive loop: see recursive loop