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Pioneer SX-1980 recap and restoration thread!

Interesting, the 5551 and ksp92 have about half the power dissipation. I was looking to sub with more wattage not less but you say this combo has been used ok.. OK, worth a try.
 
This might help.

Here is a little pictorial, I hope it helps someone.
 

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hoggwild89 said:
Have you replaced Q213 with a larger transistor? It does not look "stock"
Click to expand...

NO, IT WON'T (look "stock")... Things that needed beefing up, got beefed up for longevity.

mattsd's list uses a to-92L transistor, I specified a to-126 for several reasons I won't argue here. It may have been an old list of mine (unlikely) that specified the smaller one. I have NO idea how that occurred. Ask Mattsd...

512-KSA1013YBU to-92L ecb 160v 1a .9w 50mhz 160-320hfe $0.34 (R=60-120, O=100/200, Y=160/320)


versus my selection (after doing some reverse engineering long long ago):

512-KSA1220AYS to-126 ecb 120/a160 1.2a 1.2w/20w 175mhz 35-320hfe $0.39 (R=60-120, O=100/200, Y=160/320)


original:
2sa720 to-92 ecb 50v 0.5a 0.625w 200mhz 40-340hfe
 
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markthefixer said:
NO, IT WON'T... Things that needed beefing up, got beefed up for longevity.

mattsd's list uses a to-92L transistor, I specified a to-126 for several reasons I won't argue here. It may have been an old list of mine (unlikely) that specified the smaller one. I have NO idea how that occurred. Ask Mattsd...

512-KSA1013YBU to-92L ecb 160v 1a .9w 50mhz 160-320hfe $0.34 (R=60-120, O=100/200, Y=160/320)


versus my selection (after doing some reverse engineering long long ago):

512-KSA1220AYS to-126 ecb 120/a160 1.2a 1.2w/20w 175mhz 35-320hfe $0.39 (R=60-120, O=100/200, Y=160/320)


original:
2sa720 to-92 ecb 50v 0.5a 0.625w 200mhz 40-340hfe
Click to expand...

I took it from a list of yours a long while back. I've since changed my list to the KSA1220, but I see I didn't change it here, I'll correct that right away.
Thanks for bringing it to my attention.
 
Mark, definitely light at the end of the tunnel. -80 & -34 is normal but Q211 gets damn hot. I let it run for a about 6 or 7 minutes. Heat sink is rather uncomfortable to the touch. I heard they run hot but is this normal?

15 minutes, 156-160deg f with ir thermometer.
 
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I have participated in this thread hijack too long now.... time to set things right. (quote this post to preserve the thread flow and information below).

Please start your own thread on your sx-1980 problems.

Read and post the voltage across AWR-154 R210 and then also AWR-154 R212, both are 5.6 ohms, then take the voltage readings in volts and divide them by 5.6 for the current in amps.
Then we'll see if there's an inordinate power draw that is raising the temperatures.

IMPORTANT: The resistors R210 and R212 are hidden, and This thread's post and a few following, with pictures, explains how to access the readings easily.


Since the +/- 34v supply current also flows through R210 and R212, measure the voltage drop for the +/- 34v off board, white cement power dropping resistors R2 and R3, for elimination purposes:
R2 (awr-154 pins 31 to pin 29) (+34 supply) 360 ohms (your voltage) / 360 ohms = ?? Amps
R3 (awr-154 pins 32 to pin 30) (-34 supply) 470 ohms (your voltage) / 470 ohms = ?? Amps

I just haven't gotten a running 1980 and my IR thermometer together at the same time to take heat sink readings (yet).

Searching for posts under my username and containing "R210" (or "r210") yields a few examples of expected normal current. Here's one.
 
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markthefixer said:
EchoWars SX-1980 2SK34 replacement current source instructions


EchoWars Current Source Word Document Download Link

attachment.php
Click to expand...

In post #73 above, link to "EchoWars Current Source Word Document Download Link" does not appear to be working, anybody have an update on where to find this document.

EDIT: Nevermind...found the document here:

https://www.audiokarma.org/forums/index.php?attachments/current_regulator-doc.50480/
 
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Does anyone have an updated BOM List?
I can only find older ones with some parts are no more available.
Thank you.
 
Going up in ecap size for a power supply filter application is usually fine, and even for a Dc block or AC coupling cap. Sometimes it is a better fit because the new ones can be physically smaller than the old. watch/check the pin spacings.
coupling caps can be film, usually 5mm lead spacings or alum electrolytic, Nichicon UKL are used a lot, if in doubt use a UKL or UES (they will work for everything but are bigger, more expensive, lower V)
 
bluehills5 said:
I just re-capped a 1980 and the parts list is included in the thread below with current substitutes. Note it is very comprehensive as it includes a lot of parts (almost all caps & transistors on the power supply board, L&R amp boards and turntable pre-amp) so you may want to pick and choose what you think yours needs.
https://audiokarma.org/forums/index.php?threads/pioneer-sx1980-you-wont-believe-this.857275/page-7
Click to expand...

Unfortunately in this list there are also lots of outdated parts :(
 
like what? list them and we can help with replacements or what to do to select something equivalent.
 
I just updated the list in this thread to replace the NLA Panasonic film caps for the .47uF and .22uF values. The only things that are out of stock right now are the KSA1220 and the 220uF 160v axial caps. The KSA1220 is somewhat tough to sub, but a close equivalent is the 757-TTA004BQ, slight better free air dissipation and slightly better IC rating, but lower FT, which is not critical in this situation. The axial caps also have subs available, either 598-227TTA160M or 647-TVX2D221MDD.
 
My List for 1090 and 110, caps will follow:
Q1 2SC1775A-E 512-KSC1845FTA Mouser
Q2 2SC1775A-E 512-KSC1845FTA Mouser
Q3 2SA979-F original ordered dönberg https://www.donberg.de/katalog/2sa_979.html
Q4 2SA979-F original ordered dönberg https://www.donberg.de/katalog/2sa_979.html
Q5 2SA872A-E or D 512-KSA992FBU Mouser
Q6 2SA872A-E or D 512-KSA992FBU Mouser
Q7 2SA872A-E or D 512-KSA992FBU Mouser
Q8 2SA872A-E or D 512-KSA992FBU Mouser
Q9 2SC1775A-F or E 512-KSC1845FTA Mouser
Q10 2SC1775A-F or E 512-KSC1845FTA Mouser
Q11 2SC1775A-F or E 512-KSC1845FTA Mouser
Q12 2SC1775A-F or E 512-KSC1845FTA Mouser
Q13 2SC1904A-V or B 512-KSC3503estu old
Q14 2SC1904A-V or B 512-KSC3503estu old
Q15 2SA899A-V or B 512-KSA1381estu no stock
Q16 2SA899A-V or B 512-KSA1381estu no stock
Q17 2SA733Q or R 512-KSC2383YTA Mouser
Q18 2SA733Q or R 512-KSC2383YTA Mouser
Q19 2SC945A-Q or R 512-KSA1013YTA Mouser
Q20 2SC945A-Q or R 512-KSA1013YTA Mouser
Q21 2SA733Q or R 512-KSC2383YTA Mouser
Q22 2SA733Q or R 512-KSC2383YTA Mouser
Q23 2SC945A-Q or R 512-KSA1013YTA Mouser
Q24 2SC945A-Q or R 512-KSA1013YTA Mouser
Q25 2SC2071V or B Pair 512-KSC2690AYSTU Mouser
Q26 2SC2071V or B 512-KSC2690AYSTU Mouser
Q27 2SA939V or B Pair 512-KSA1381ESTU no stock
Q28 2SA939V or B 512-KSA1381ESTU no stock
Q29 2SC2238C-O or Y MJE15033G Mouser
Q30 2SC2238C-O or Y MJE15033G Mouser
Q31 2SA968C-O or Y MJE15032G Mouser
Q32 2SA968C-O or Y MJE15032G Mouser
Q33 2SC869C or D 512-KSC1845FTA Mouser
Q34 2SC869C or D 512-KSC1845FTA Mouser
 
A question about the caps in 109 and 110:
How critical would be the difference for the C33/C34 if I use 0,22uF instead the original 0,2uF.
I try to understand how close the values must be.
Thank you.
 
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