Further to my Sony TA-1150 blown fuse post....opinions on my transistor choices?

62vauxhall

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#1
I micky moused some fuses to see what the amp did on a DBT and no surprize, the bulb stayed bright. A rebuild thread on that other forum mentioned the bridge rectifier Sony used was prone to failure so I pulled it, checked it and it was OK. As were it's capacitors. Next up, the output transitors.

Two of those had failed as did some others on the power amp board. I pulled and checked all of them.

Summerizing my thumbs up or thumbs down opinion request:

Output transistors - MJE15032 (with center collector leg removed) sub for 2SC1061 / 2SC1060.
Ouptput transitors - MJE15033 (with center collector leg removed) sub for 2SB856 / 2SA670.
KSA1220 sub for 2SA706
KSC2690 sub for 2SC1364 / 2SC633A - heatsink temperature bias adjust.

Not asking for much am I?

Sony TA1150 power amp.JPG
 
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62vauxhall

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#4
Thanks Glen, I'll take your comment as gospel truth.

I looked at those same data sheets. One of these years I will understand what specs to focus on. I am always 2nd guessing . I've been told I think (or worry} too much.

The pieces I ordered should get here end of next week. Manual says 25mv bias. Think that will do for the new output devices?

I have on hand the appropriate electrolytics to replace those on this power amp board. I figure I might as well do that while it's disengaged from the chassis. The power supply is elsewhere and I thought I'd put fresh electrolytics there too. Small ones anyway. The rest I think I'll leave alone.

EDIT: One of the things that made me question the choice was how the datasheets described them. "Low frequency power amplifer" for the old transistors and "high frequency driver" for the new ones.
 
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grapplesaw

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#10
Really, 70V? I thought it was 50V.

EDIT: Have ON MJE15032/33 gone up in price recently?
Gary I have been buying from Arrow, Newark and Mouser on their Canadian sites I get most from mouser. They ship overnight free on $100+ orders
Also seams that they only add get as well. Newark is worth checking as they have deep discounts on some pieces. They ship for fee over $200 orders. Also they add both our taxes. You can save 15% for the next three day using BONUS15 code
 

62vauxhall

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#11
Thanks Glen. I ordered from Digikey Ca. - the third time since living here. Arrivals have been really quick. Free shipping over $100 so I bulked up the order a bit. Couldn't think of much else when I placed the order so am getting excess numbers of the transistors for this job.

I remarked on MJE15032/33 pricing because I've needed MJE15033's before and thought I read somewhere that they were going out of production. Probably wrong, but I thought the under 10 piece cost then was well under $2 per. This time $2.21 or something. I need four of each but bought greater than threshold numbers for better pricing.

Of course after placing the order, other items came to mind I could have bought and not gone overboard with the transistors.

Most often, I've ordered from Mouser or Digikey. I haven't used Newark for ages. I do check but most often they havent had what I've wanted. And I wasn't aware of Arrow. I'll have a look at their site as well as Quest that you mentioned.
 
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grapplesaw

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#12
Of course after placing the order, other items came to mind I could have bought and not gone overboard with the transistors.[/QUOTE]
My life exactly
 

Gepetto

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#14
Thanks Glen. I ordered from Digikey Ca. - the third time since living here. Arrivals have been really quick. Free shipping over $100 so I bulked up the order a bit. Couldn't think of much else when I placed the order so am getting excess numbers of the transistors for this job.

I remarked on MJE15032/33 pricing because I've needed MJE15033's before and thought I read somewhere that they were going out of production. Probably wrong, but I thought the under 10 piece cost then was well under $2 per. This time $2.21 or something. I need four of each but bought greater than threshold numbers for better pricing.

Of course after placing the order, other items came to mind I could have bought and not gone overboard with the transistors.
The MJE15XXX series of devices are industry workhorse parts and are not going EOL.
 

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#17
Gary: Like being reacquainted with an old friend - good to see you got the Sony fixed.

Nando.
 

62vauxhall

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#18
Looking at it does make me recall what was going on in my life when I bought a brand new TA-1150 in 1973. And oh my god, do I ever wish I could be in that space again.

A bittersweet feeling....the good times, the optomism then the wrong decisions, the missed opportunities.
 

Elite-ist

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#19
I might have to crack open a cool Pale Ale and reflect upon your words, Gary.

You're in good company. It's David Gilmour's birthday, today. Even he had regrets and failed opportunities.

158228777_5133889623351744_7830587577932999334_n.jpg

Nando.
 

Wheel-right

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#20
Looking at it does make me recall what was going on in my life when I bought a brand new TA-1150 in 1973. And oh my god, do I ever wish I could be in that space again.

A bittersweet feeling....the good times, the optomism then the wrong decisions, the missed opportunities.
We all been having those kinda thoughts lately with what's gone on in the past year. Great job on that Sony and the America tape in the deck will for sure take a person back in time.
 
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