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Equipment Repairs => DVD/VIDEO/Home Cinemas/Hi-Fi/Mp3/Camcorder => Topic started by: Turnip on May 13, 2017,12:08:52

Title: Pioneer SA-506 Stereo Amplifier
Post by: Turnip on May 13, 2017,12:08:52

Hi folks,

Have one where very occasionally get a loud crackle on one channel but can't track it down with heat or freezer.

Note Sanyo O/P transistors 2SB616A and 2SD586A are horribly expensive.

Wonder if there's a known issue ?   Thanks - Chris.

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: downunder on May 14, 2017,04:43:07

Hi Chris, Do you need a schematic?           Bruce

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: jordan on May 14, 2017,06:47:25

 Pioneer SA-506

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: Turnip on May 14, 2017,09:38:56

Hi Bruce and Jordan, thanks, had a schematic but yours is better. Problem is intermittent where it nearly blows the cone out of one speaker and the cone stays out 'till the amp is switched off.

Obviously a lot of DC present but on just one channel. Would have replaced the O/P transistors but they're a rather special old fashioned type with tabs on either side rather than the top. Could fit standard NPN/PNP 100v 5a with a bit of metal work but rather keep original - Chris.

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: downunder on May 15, 2017,04:12:24

Hi Chris,

Rather strange transistors, those. Don't know how you feel about ordering from China, but UT Source have the 2SB616A, not the other.

Aliexpress have the 2SD586A, but not the other. See how you go.                          Bruce

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: Turnip on May 15, 2017,08:57:24

Thanks Bruce,

Got down to it with more heat and freezer, eventually found 2SA798 dual PNP Q201 faulty. To Ebay where they're Hen's teeth again - Cheapest found in Australia but post a killer, so wired up a pair of BC556 back to back - Pinout BCECB emitters joined together - OK so far, speaker DC voltage nicely zero - Chris.

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: downunder on May 16, 2017,04:32:00

A little bit of English ingenuity, eh!

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: Turnip on September 29, 2017,12:16:00

Hi Bruce,

Amp back today for crackling, same channel. Had switched the suspect 2SA798 to prove the point and the other one has now gone duff.

Did it as a freebie with a bit of a smile, as can't charge twice for the same problem - Chris.

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: downunder on September 30, 2017,03:35:35

Thanks for the heads-up, Chris. Don't know about you, but I hate audio with a passion and tend to steer clear of it.

Bruce

Title: Re: Pioneer SA-506 Stereo Amplifier
Post by: Turnip on September 30, 2017,13:10:14

Hi Bruce,

Was a bit of fun - Getting to realise if you get a problem with a device, if you don't change 'em all they'll come back to bite you.

Seem to recall you after an idler tyre for a record player as you had one with a bit of a bump after lying idle for 40 years.

You just love antique audio.

Daughter has just returned from a holiday in France with a 1951 radio with something like an EM34 sticking out of the middle. She was awfully pleased as woodwork was in best 'Art Crappo' style, but on trying attach an aerial, became shocked by something or other.

Job for tomorrow - Chris.