Pioneer Sx-1980 Help

jleaman · 9th May 2010, 08:15 PM

I have a powering up Sx-1980, but no sound, so removed the bottom plate to see that most of the small capacitors are all swollen / bubbled, and all the plastic wrap has all shrunk on them.

I am not sure if the amplifier is worth fixing or not. None of the fuse's are blown, and lights all power up. However the relays don't click, probably because the protection circuit is toast, I am assuming that this board is the board that protects the main amplifier part of this unit.

Can some one help with some tests or ideas if this is fixable, or should i just part it out to those who need parts ?

Jase

nigelwright7557 · 9th May 2010, 09:06 PM

You need to do some basic tests to see why it isnt working.
Check power supply.
Check output dc volts.

You need a schematic to go much further than that.
But you need to check output transistors.
Also need to check any protection circuits.

If it is worth fixing I would start by replacing all the electrolytics.

planet10 · 9th May 2010, 09:12 PM

If anything like the 1280 i had, a killer trafo & heatsinks...

dave

planet10 · 9th May 2010, 09:23 PM

Pioneer SX-1980 Regulator Driving Me Insane!
Finally a Pioneer SX 1980 is it a Blessing or Curse? - AudioKarma.org Home Audio Stereo Discussion Forums

Pioneer SX-1980 service manual and schematics | FSM ID: 64025

More than a few buttons and knobs!!!

dave

jleaman · 10th May 2010, 12:15 AM

Quote:

Originally Posted by planet10

Pioneer SX-1980 Regulator Driving Me Insane!
Finally a Pioneer SX 1980 is it a Blessing or Curse? - AudioKarma.org Home Audio Stereo Discussion Forums

Pioneer SX-1980 service manual and schematics | FSM ID: 64025

More than a few buttons and knobs!!!

dave

yup that's the beast, its a huge HEAVY beast too! id say 9&3/4's out of 10 capacitors on the main middle board are toast

Transformer is pretty useless tome, way to high of voltage.

Stormrider · 10th May 2010, 01:23 AM

The big silver faced Pioneers are worth quite a bit to collectors. I had an SX1250 and it fetched good money on ebay. The SX1980 was the biggest and baddest of the era.

It's definitely worth repairing.

tiefbassuebertr · 10th May 2010, 10:09 AM

Quote:

Originally Posted by Stormrider

The big silver faced Pioneers are worth quite a bit to collectors. I had an SX1250 and it fetched good money on ebay. The SX1980 was the biggest and baddest of the era.

It's definitely worth repairing.

I have repair the SX1980 for my brother 1 year ago; in the aera of the discrete voltage regulators you will find many "hot spots" through termal overloading. After replace the caps in this aeras and cleaning the variable capacitor in the FM front end the device work very fine.
My english isn't good. What means this:
...and baddest of the era.

Stormrider · 10th May 2010, 12:04 PM

It was one of the most powerful receivers back then.

9th May 2010, 08:15 PM	#1
jleaman Banned Join Date: Apr 2002	Pioneer Sx-1980 Help I have a powering up Sx-1980, but no sound, so removed the bottom plate to see that most of the small capacitors are all swollen / bubbled, and all the plastic wrap has all shrunk on them. I am not sure if the amplifier is worth fixing or not. None of the fuse's are blown, and lights all power up. However the relays don't click, probably because the protection circuit is toast, I am assuming that this board is the board that protects the main amplifier part of this unit. Can some one help with some tests or ideas if this is fixable, or should i just part it out to those who need parts ? Jase

9th May 2010, 09:06 PM	#2
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	You need to do some basic tests to see why it isnt working. Check power supply. Check output dc volts. You need a schematic to go much further than that. But you need to check output transistors. Also need to check any protection circuits. If it is worth fixing I would start by replacing all the electrolytics. __________________ http://www.murtonpikesystems.co.uk PCBCAD40 pcb design software.

9th May 2010, 09:12 PM	#3
planet10 frugal-phile(tm) diyAudio Moderator Join Date: Oct 2001 Location: Victoria, BC, NA, Sol III Blog Entries: 4	If anything like the 1280 i had, a killer trafo & heatsinks... dave __________________ community sites t-linespeakers.org, frugal-horn.com ........ commercial site planet10-HiFi p10-hifi forum here at diyA

10th May 2010, 01:23 AM	#6
Stormrider diyAudio Member Join Date: Apr 2006 Location: Connecticut	The big silver faced Pioneers are worth quite a bit to collectors. I had an SX1250 and it fetched good money on ebay. The SX1980 was the biggest and baddest of the era. It's definitely worth repairing. __________________ AJ

10th May 2010, 12:04 PM	#8
Stormrider diyAudio Member Join Date: Apr 2006 Location: Connecticut	It was one of the most powerful receivers back then. __________________ AJ


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