Pioneer sx-1080 - advise on re-cap.

q2 has been destroyed, and D8 along with it.

Q1 is also probably dead, even if NEW, test it carefully out of circuit, it could have been destroyed by the faulty q2 after the resistor R3 was replaced.

q3, q4 are ok

Q5 and Q6 also dead, they were probably damaged when q2 blew up, since they are directly connected to Q2, D8.

In these situations, the best advice when I am unable to give any, would be to remove the transistors one at a time, and do the 6-way diode test on each of them, test the diodes out of circuit and test the resistors.

the 28v on q5c and q6c with power off is the charge on C23, 2200 uf 35v from when it was turned on, there is nowhere to drain it off.

now you see why I check everything when replacing parts. I'm slightly sorry I didn't insist on parts testing before powering up after replacing R3.
 
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markthefixer said:
q2 has been destroyed, and D8 along with it.

Q1 is also probably dead, even if NEW, test it carefully out of circuit, it could have been destroyed by the faulty q2 after the resistor R3 was replaced.

q3, q4 are ok

Q5 and Q6 also dead, they were probably damaged when q2 blew up, since they are directly connected to Q2, D8.
Click to expand...
I have pooled a set of Q1,Q2,Q5,Q6 and D8 for replacement. (Q1 & Q6 are old, but tested good, no more new in stock)

In these situations, the best advice when I am unable to give any, would be to remove the transistors one at a time, and do the 6-way diode test on each of them, test the diodes out of circuit and test the resistors.
Click to expand...
Apart from removing all transistors, one at a time and do the 6-way test, please confirm that I should:

* replace D8 and unsolder diodes D9, D10, D11 in one end for test, and that I can leave out D1-D7 of the test.
* lift one leg on the 15 resistors between the fuses and the Q4-end of the board, and test resistance.

the 28v on q5c and q6c with power off is the charge on C23, 2200 uf 35v from when it was turned on, there is nowhere to drain it off.
Click to expand...
OK, I discharged it using a resistor.
now you see why I check everything when replacing parts. I'm slightly sorry I didn't insist on parts testing before powering up after replacing R3.
Click to expand...

I will await your answer before I begin.
 
After a healthy break I'm back at again.

HTML: 
============================================
action		Comment
----------------------------------------------------------
replaced Q1	fried, repl.w. orig D712
replaced Q2	fried
replaced Q5	Values slightly off 
Keept Q6	Values as new component
replaced D8	fried
Power on readings:
---------
pin Volt
7 +62.7 (+62.0)
8 -62.7 (-62.0)
16 +13.0 (+13.0)
19 +83.0 (+76.0)

20 +35.5 (+33.0)
22 +63.5 (+60.0)
23 +23.4 (+23.0)

25 -23.0 (-23.0)
27 -62.4 (-60.0)
28 -13.5 (-13.0)

Q1e: +63.9 V (+60.0)
Q1b: +64.4 V (+60.6)
Q1c: +83.0 V

Q2e: +14.8 (+14.2)
Q2b: +15.3 (+14.8)
Q2c: +64.4 (+60.6)

Q5e: +13.7 V (+13.0)
Q5b: +14.3 V (+13.6)
Q5c: +25.7 V (=Q6c)

Q6e: +14.3 V (+13.6)
Q6b: +14.8 V
Q6c: +25.7 V (=Q5c)

D8,cath: +14.7 V
D8,an: +0.000 V

So, now I am once again ready to proceed with the power amps, but what can I do to prevent the previous set backs that have occurred every time I start adjusting VR1/VR2?
 
D5/stv4h

I finally managed to get everything fixed on this unit :thmbsp:

Both amps have been rebuild and are adjusted to specs, and everything was fine, until I managed to snap one of the wires to the D5/STV4H thermistor/varistor or what's it's called.

There is barely 1mm of visible wire, after I have been scrathcing the epoxy-filling a bit, and attempts to solder the wire piece back on seems to cause the filling to melt, preventing a good adhesion.

I would like to ask if anyone can inform of how deep you dig in to the filling in the housing to expose sufficient wire to solder on, without causing "deadly" damage.

I suppose a repair is the only solution, since these are nowhere to be found.

It would just be unbearable if it all should fail, now that it finally is made to work, and should be back in operation :pity:
 

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I will note that I use stranded wire, to eliminate most possibility of the problem reoccurring.

attachment.php
 
Disapointed

Now everything is in place, lamps are working and it has been re-positioned to its location in the living room.

It barely generates heat in the large power heatsinks - the heat that can be felt is coming from the power supply - not overly hot, but then again I haven't had cranked up yet.

So now I have nice looking, clean, almost totally refurbished receiver, that sounds.....

EXACTLY the way it did before the re-cap :(.

I hear no improvement what so ever - no crisp treble (the main reason I went ahead), lots of bass (hard to tell if the bass is muffled as well). General sound experience is muffled, strangulated and uninspiring. The sound does react to handling of the controls - ie. bass & treble isn't locked.

I had my cheap speakers hooked up to the temporary SANSUI 6060 (year 1976) substitute, and it (the SANSUI) made them sound really good - much better than the SX-1080 did. This goes to proof that both my hearing (even though it isn't what it used to be ;) ) AND the speakers are OK - the SX-1080 doesn't perform, even with my ELAC 253s connected...

Strange thing is, that there is a nice open tone (with treble) in the head-set output - is this a clue?

What I now wonder is, if there is any thing more I can do - obviously the Tone Control board could be investigated, but all electrolytes have been replaced here - could it be replacing that the two trannys and the ceramics and mylars ( C5-C12) will help?

As it is now all the effort has had no effect....
 
ultrasparc said:
Now everything is in place, lamps are working and it has been re-positioned to its location in the living room.

It barely generates heat in the large power heatsinks - the heat that can be felt is coming from the power supply - not overly hot, but then again I haven't had cranked up yet.

So now I have nice looking, clean, almost totally refurbished receiver, that sounds.....

EXACTLY the way it did before the re-cap :(.

I hear no improvement what so ever - no crisp treble (the main reason I went ahead), lots of bass (hard to tell if the bass is muffled as well). General sound experience is muffled, strangulated and uninspiring. The sound does react to handling of the controls - ie. bass & treble isn't locked.

I had my cheap speakers hooked up to the temporary SANSUI 6060 (year 1976) substitute, and it (the SANSUI) made them sound really good - much better than the SX-1080 did. This goes to proof that both my hearing (even though it isn't what it used to be ;) ) AND the speakers are OK - the SX-1080 doesn't perform, even with my ELAC 253s connected...

Strange thing is, that there is a nice open tone (with treble) in the head-set output - is this a clue?

What I now wonder is, if there is any thing more I can do - obviously the Tone Control board could be investigated, but all electrolytes have been replaced here - could it be replacing that the two trannys and the ceramics and mylars ( C5-C12) will help?

As it is now all the effort has had no effect....
Click to expand...
I have been reading your post. If it makes you feel better I am so sorry. I have learned a lot I wish you guys could figure it out. Are you going to keep trying to do something or are you done? Wish you all the best!
 
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what is your main signal source, and has everything between that point and the power amps been recapped?

repost the list of parts replaced, and what they were replaced with, since you are "over across the pond" and not using the mouser list in toto..., so I can try to spot any bottlenecks.
 
Gdl82 said:
I have been reading your post. If it makes you feel better I am so sorry. I have learned a lot I wish you guys could figure it out. Are you going to keep trying to do something or are you done? Wish you all the best!
Click to expand...

Thanks for the kind words.

Yeah, I'm not ready to quit yet, however it is a little discouraging the way thing have turned out, but the perhaps Mark the Magician have something up his sleeve - he just responded :)
 
markthefixer said:
what is your main signal source, and has everything between that point and the power amps been recapped?

repost the list of parts replaced, and what they were replaced with, since you are "over across the pond" and not using the mouser list in toto..., so I can try to spot any bottlenecks.
Click to expand...

Hi Mark, thanks for responding :)

Power supply and power amps have had all electrolytic caps, resistors, zeners, diodes and transistors replaced, all other boards have only had caps replaced. (see attached list)

I use the receiver for CD (AUX), turntable (Phono), FM and TV/DVD (Tape) listening, and since it is the sound-hub of the house, TV is dominant, and the music is secondary :( - and more so due to the degrading sound.

TV-cable is L,R-phono both ends, definitely not living up to today's cable-standards, but has always been satisfying for me, also I have been very happy with the sound of concert-DVDs (same cable, via TV).

Today I had another turntable (Technincs SL-3300, Ortofon Concorde Pro) attached, but with same poor result.

Seems also some CD's (Savage Garden, Affirmation,1999) are exaggerated in the bass, at medium volume loudness must be flipped off and bass must be in the negative to avoid severe muffling, but I have also have had a CD (Curtis Steigers, 1991) with pleasant sound. If it was as good as in the old days I can't tell, it's just better than the bad one, and they definitely used to sound better.

Once again I find the sound in the headset is pretty good, which keeps me think that the problem is the speakers (ELAC 253), but then again they used to sound awesome.

Looking forward to see what you can suggest.
/Ole

PS: I do listen to Heavy as well ;)

edit: Pick-up was upgraded along the way to the Elys 2, but again, no improvement detected.
 

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ultrasparc said:
Hi Mark, thanks for responding :)

Power supply and power amps have had all electrolytic caps, resistors, zeners, diodes and transistors replaced, all other boards have only had caps replaced. (see attached list)

I use the receiver for CD (AUX), turntable (Phono), FM and TV/DVD (Tape) listening, and since it is the sound-hub of the house, TV is dominant, and the music is secondary :( - and more so due to the degrading sound.

TV-cable is L,R-phono both ends, definitely not living up to today's cable-standards, but has always been satisfying for me, also I have been very happy with the sound of concert-DVDs (same cable, via TV).

Today I had another turntable (Technincs SL-3300, Ortofon Concorde Pro) attached, but with same poor result.

Seems also some CD's (Savage Garden, Affirmation,1999) are exaggerated in the bass, at medium volume loudness must be flipped off and bass must be in the negative to avoid severe muffling, but I have also have had a CD (Curtis Steigers, 1991) with pleasant sound. If it was as good as in the old days I can't tell, it's just better than the bad one, and they definitely used to sound better.

Once again I find the sound in the headset is pretty good, which keeps me think that the problem is the speakers (ELAC 253), but then again they used to sound awesome.

Looking forward to see what you can suggest.
/Ole

PS: I do listen to Heavy as well ;)

edit: Pick-up was upgraded along the way to the Elys 2, but again, no improvement detected.
Click to expand...

Just bumpin up...
 
When the headphones sound good, do they still sound good with a speaker load?

The headphones and speakers are both downstream of the protection relay, so if the speakers sound bad, and are causing it through a protection relay contact defect, the headphones should not escape that influence.
 
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markthefixer said:
When the headphones sound good, do they still sound good with a speaker load?

The headphones and speakers are both downstream of the protection relay, so if the speakers sound bad, and are causing it through a protection relay contact defect, the headphones should not escape that influence.
Click to expand...

Yes, headphones sound the same regardless of speaker load.
 
I been thinking :scratch2:

What I imagine is that maybe I can pinpoint the problem a bit by using the sx1080 in a pre-amp function? If I remove the pre-amp bridge and plug a cable in pre-amp-out on the sx1080 and plug the other end in, for example, the AUX on another amplifier, which will be the power amplifier, will it not show if the sx1080 pre-amp or power amp is the problem? (Tone controls set to neutral on (power-)amplifier 2, and tone is adjusted on sx1080)

And vice versa, move the cable from the pre-out to pre-inp on sx1080 and the other end of the cable (source) to for example Tape-rec (out) from amplifier 2? (Tone controls set to neutral on sx1080, and tone adjustment on amplifier 2)

Yes, I know I don't know, so if this a big laugh, please be gentle :saywhat: :stupid:
 
I will have a Sansui 6060 available later this week, which I will use as the second amp (power amp, when testing pre-amp in 1080).

Perhaps someone will care to comment/correct my thoughts on the setup, before i get going?

Testing 1080 pre-amp:
  1. power OFF 1080 and Sansui
  2. remove preamp bridge plugs
  3. connect 1080 pre-amp out to Sansui AUX
  4. move speaker cables from 1080 to Sansui :D
  5. set bas/treble to neutral on Sansui
  6. set volume on 1080 to 0 initially?
  7. activate source (CD) on 1080
  8. power on 1080 and Sansui
  9. turn volume on Sansui to desired level (0 ?)
  10. carefully increase volume on 1080
  11. play with bas & treble on 1080 ? (and make a mental note of sound flavour)

Testing 1080 power-amp:
  1. Power off 1080 and Sansui
  2. Power off 1080 and Sansui
  3. move RCA cable from pre-out to pre-inp on 1080
  4. move RCA cable from AUX to Tape rec on Sansui
  5. move speakers to 1080
  6. set bas/treble to neutral, de-select loudness and tone on Sansui
  7. set volume on Sansui to 0
  8. set volume on 1080 to 0 ?
  9. activate source on Sansui (CD or tuner)
  10. power on 1080 and Sansui
  11. turn volume on 1080 to desired level
  12. carefully increase volume on Sansui to desired level ?
  13. play with bas & treble on 1080 ? or Sansui ? (and make a mental note of sound flavour)

Alternatively, can f.inst. the CD-player safely be plugged directly to the pre-inp on 1080, instead of using the Sansui as source?

Br
Ole
 
SX1080 pre-amp problem

I managed to make that pre-amp test last night, and I find that this is here the problem lies, ie. the sx1080 acting as pre-amp with Sansui as power amp, delivers the same poor sound, as does the sx1080 by itself.
(The other way around can't be without a proper pre-amp, I know now)

So if I want to verify that the sx1080 can act satisfactory as power amp, I will need to get my hands on a pre-amp (I've got my eyes on a Harman Kardon KH825 for about a hundred bucks - scratchy pots, but worth it?)

if I want to start looking for a place to improve, will it be the Flat Amplifier Assembly GWG-112 ? I could start by checking voltages?
 
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