SA-9800 Re-Work Begins

I am starting a new thread, as the title of the old thread here - http://www.audiokarma.org/forums/showthread.php?t=344654
is not proper as to the current work in progress on this amp.

I am back on the 9800. It is the only item on the bench right now with full focus. I have tested all functions, and they all work properly, with some clicking on switch throws and static on pot turns here and there.

I took the top and bottom covers and shield covers (x2) off and the faceplate and deoxited (D5) all switches and pots THOROUGHLY. Been just doing some general cleaning up of the unit. I will check the power supply board voltages to see where it stands tomorrow (I hope). And take a closer look at the caps and start comparing my actual 9800 to the current list(s).

Here we go...!

Was able to work with the 9800 today quite a bit and everything seems to be looking pretty decent. Here are some measurements:

AWR-194 (Power Supply Assy)

pins 1&2: -53v, should be -52v, regulated
pins 3&4: +53v, should be +52v, regulated
pins 5&6: +32v, should be +32v, regulated
pin 7: +19v, should be +18v, regulated, provides power for display circuit
pin 8: 0v, ground
pin 9: -50v, raw, unregulated
pins 10&11: -32v, should be -32v, regulated
pin 12: +49v, raw, unregulated
pin 13: +69v, raw, unregulated
pin 14: 0v, ground
pin 15: -70v, raw, unregulated
pin 16: +6.7vac, this is an AC voltage
pin 17: +53.4vac, this is an AC voltage
pin 18: +53.7vac, this is an AC voltage

It seems that these voltages look good in review of many previous posts, keeping newer posts in the frontal lobe.

I got the offset and bias adjusted with stable results very quickly. All functions working fine and the deoxit job worked well, with no static or pot/switch issues. Outputs are clear and sound real nice.

Noticed some darkness from heat on the power supply board in the following areas (see pictures):

Around Q11 2SD712 and Q12 2SB682 (TO-92)
Around R20 330 1w and D10 MZ-177
Around the cluster or transistors of Q3 2SA733A, Q9 2SC945A, Q1 2SC1735, Q5 2SK34

Also, I understand it is wise to replace the axial 220 uF caps C2 & C3 on this board, as they commonly go bad.

I did not notice any heat issues or cold solders on the amp boards. Surprisingly...

If all goes well, I will begin the cap list right away.

Any suggestions on the current state of things?

q7,q8,q11,q12 (2sa912, 2sc1885 to-92L) on the amp (7ma) get hot and should be to-126 devices, should be the same from on the 3900 in those circuit positions (q115,q116 2sa905 q109,q110 2sc1915 to ).


512-KSA1220AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.39 (R=60-120, O=100/200, Y=160/320)
512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40


standard now on 3900 and in that functional position on other NSA amps.

markthefixer said:

q7,q8,q11,q12 (2sa912, 2sc1885 to-92L) on the amp (7ma) get hot and should be to-126 devices, should be the same from on the 3900 in those circuit positions (q115,q116 2sa905 q109,q110 2sc1915 to ).


512-KSA1220AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.39 (R=60-120, O=100/200, Y=160/320)
512-KSC2690AYS to-126 ecb 120/a160 1.2a 20w 155mhz 35-320hfe $0.40


standard now on 3900 and in that functional position on other NSA amps.

Click to expand...

You got it Mark. I will put those on my parts list for Mouser.

Need some guidance before placing an order for Monday:

1. Anything else get replaced on the Amp boards other than Q7, Q8, Q9, Q10, Q11, Q12 and possibly the 220 ohm resistors (looks like 7 of them on each Amp board) you mentioned? Bourns trim/resistor pots?

3. Should I replace anything on the Power Supply Board (AWR-194) as "preventative maintenance/upgrades"?

3. What about these showing some board heat (Power Supply Board/AWR-194)? Leave in or replace?
Q11 2SD712 & Q12 2SB682 (TO-92)
Q3 2SA733A, Q9 2SC945A, Q1 2SC1735, Q5 2SK34

4. And also showing the most significant heat on the Power Supply Board. Recommended replacements?:
R20 330 1w (pretty standard, right?)
D10 MZ-177 (Would 1N5248, Mouser P/Ns 78-1N5248B-TAP or 512-1N5248BTR be good?)

oh boy... yes... :sigh:

SA-9800 Cap List

Spent the better part of the day working this list up and verifying with the unit on the bench. If you could be so kind as to look it over and let me know what you think, I would highly appreciate it. All currently in stock at Mouser and saved to a fresh project.

Power Supply
awr-194 c2 220uf 80v ceb axial 220 100 647-TVX2A221MCD
awr-194 c3 220uf 80v ceb axial 220 100 647-TVX2A221MCD
awr-194 c4 47uf 10v cea 47 10 647-UPW1A470MDD6
awr-194 c7 47uf 63v cea 47 100 647-UPW2A470MPD1TD
awr-194 c8 47uf 63v cea 47 100 647-UPW2A470MPD1TD
awr-194 c9 47uf 63v cea 47 100 647-UPW2A470MPD1TD
awr-194 c10 47uf 63v cea 47 100 647-UPW2A470MPD1TD
awr-194 c13 2.2uf 50v cea 2.2 50 647-UPW1H2R2MDD
awr-194 c14 2.2uf 50v cea 2.2 50 647-UPW1H2R2MDD
awr-194 c15 100uf 35v cea 100 35 647-UPW1V101MPD1TD
awr-194 c16 100uf 35v cea 100 35 647-UPW1V101MPD1TD
awr-194 c17 10uf 80v cea 10 100 647-UPW2A100MED

Amp Left
gwh-129 c1 2.2uf 50v ceanl 2.2 50 647-UKL1H2R2MDDANA
gwh-129 c11 47uf 63v cea 47 100 647-UPW2A470MPD1TD
gwh-129 c13 47uf 63v cea 47 100 647-UPW2A470MPD1TD

Amp Right
gwh-130 c2 2.2uf 50v ceanl 2.2 50 647-UKL1H2R2MDDANA
gwh-130 c12 47uf 63v cea 47 100 647-UPW2A470MPD1TD
gwh-130 c14 47uf 63v cea 47 100 647-UPW2A470MPD1TD

EQ
gwf-116 c3 100uf 6v ceanl 100 10 647-UKL1A101KED1TD
gwf-116 c4 100uf 6v ceanl 100 10 647-UKL1A101KED1TD
gwf-116 c5 100uf 6v ceanl 100 10 647-UKL1A101KED1TD
gwf-116 c6 100uf 6v ceanl 100 10 647-UKL1A101KED1TD
gwf-116 c7 100uf 6v ceanl 100 10 647-UKL1A101KED1TD
gwf-116 c8 100uf 6v ceanl 100 10 647-UKL1A101KED1TD
gwf-116 c9 100uf 35v cea 100 35 647-UPW1V101MPD1TD
gwf-116 c10 100uf 35v cea 100 35 647-UPW1V101MPD1TD
gwf-116 c11 100uf 35v cea 100 35 647-UPW1V101MPD1TD
gwf-116 c12 100uf 35v cea 100 35 647-UPW1V101MPD1TD
gwf-116 c17 100uf 16v cea 100 16 647-UPW1C101MED
gwf-116 c18 100uf 16v cea 100 16 647-UPW1C101MED
gwf-116 c19 100uf 16v cea 100 16 647-UPW1C101MED
gwf-116 c20 100uf 16v cea 100 16 647-UPW1C101MED
gwf-116 c23 4.7uf 25v ach-318 np 4.7 25 647-UES1E4R7MDM
gwf-116 c24 4.7uf 25v ach-318 np 4.7 25 647-UES1E4R7MDM
gwf-116 c35 220uf 10v cea 220 10 647-UPW1A221MED
gwf-116 c36 220uf 10v cea 220 10 647-UPW1A221MED
gwf-116 c41 4.7uf 25v ach-318 np 4.7 25 647-UES1E4R7MDM
gwf-116 c42 4.7uf 25v ach-318 np 4.7 25 647-UES1E4R7MDM
gwf-116 c45 47uf 50v cea 47 50 647-UPW1H470MED
gwf-116 c46 47uf 50v cea 47 50 647-UPW1H470MED

Protection
awm-163 c1 470uf 6v cea 470 10 647-UPW1A471MPD
awm-163 c2 220uf 16v cea 220 25 647-UPW1E221MPD
awm-163 c3 4.7uf 50v cea 4.7 50 647-UPW1H4R7MDD

Filter
gws-176 c39 1uf 50v ceanl 1 50 647-UKL1H010MDDANA
gws-176 c40 1uf 50v ceanl 1 50 647-UKL1H010MDDANA
gws-176 c41 2.2uf 50v ceanl 2.2 50 647-UKL1H2R2MDDANA
gws-176 c42 2.2uf 50v ceanl 2.2 50 647-UKL1H2R2MDDANA

TC
gwg-124 c7 4.7uf 25v ach-318 np 4.7 25 647-UES1E4R7MDM
gwg-124 c8 4.7uf 25v ach-318 np 4.7 25 647-UES1E4R7MDM
gwg-124 c19 10uf 16v ceanl 10 16 647-UKL1C100KDDANA
gwg-124 c20 10uf 16v ceanl 10 16 647-UKL1C100KDDANA
gwg-124 c29 4.7uf 25v ceanl 4.7 25 647-UKL1E4R7KDDANA
gwg-124 c30 4.7uf 25v ceanl 4.7 25 647-UKL1E4R7KDDANA
gwg-124 c31 47uf 35v cea 47 35 647-UPW1V470MED
gwg-124 c32 47uf 35v cea 47 35 647-UPW1V470MED

Indicator
awv-002 c3 1uf 50v cea 1 50 647-UPW1H010MDD1TD
awv-002 c4 1uf 50v cea 1 50 647-UPW1H010MDD1TD
awv-002 c5 2.2uf 50v cea 2.2 50 647-UPW1H2R2MDD
awv-002 c6 2.2uf 50v cea 2.2 50 647-UPW1H2R2MDD
awv-002 c9 47uf 10v cea 47 10 647-UPW1A470MDD6
awv-002 c10 220uf 25v cea 220 25 647-UPW1E221MPD
awv-002 c11 3.3uf 50v cea 3.3 100 647-UPW2A3R3MDD
awv-002 c12 3.3uf 50v cea 3.3 100 647-UPW2A3R3MDD

Also, there are a number of other types of caps in this thing. Like a handful (7 to be exact) on the EQ Board that appear to be polystyrene film caps. Leave them, or replace them? There are some other poly type caps throughout as well. Leave them, or replace them?

Thanks for the help!

markthefixer said:

oh boy... yes... :sigh:

Click to expand...

Hi MTF. If you could be so kind to post further insight (I know you are on extremely tight time) I'd appreciate it greatly. Want to replace all components while the boards are loose. Only want to loosen them up one time, if possible due to the wire wraps.

These are the main caps (x4):
667-ECE-T1KA153FA (Panasonic THA Series 15,000uf 80v)

Thanks.

we know power supply transistors run hot

we know certain protect transistors have issues

we know some nsa amp transistors are run hot

we also know (7800) some PHONO transistors are run TOO HOT. (make em TO-126 if not TO-220(look at 1980 phono, it uses to-220's!!!))

all these are my STARTING points for a protracted analysis session.... at least half a day??...

markthefixer said:

we know power supply transistors run hot

we know certain protect transistors have issues

we know some nsa amp transistors are run hot

we also know (7800) some PHONO transistors are run TOO HOT. (make em TO-126 if not TO-220(look at 1980 phono, it uses to-220's!!!))

all these are my STARTING points for a protracted analysis session.... at least half a day??...

Click to expand...

Please see if my replacement suggestions are solid. They are all in BOLD. Are these good replacements?

1. The power supply board has a total of 12 transistors:

Q1 & Q2 2SC1735 Replace with 512-KSC2383YTA
Q3 & Q10 2SA733A Replace with 512-KSA1013YBU
Q4 & Q8 2SA904A Replace with 512-KSA992FBU
Q5 & Q6 2SK34 Replace with Sk34 (I currently have from Ampslab)
Q7 2SC1914A Replace with 512-KSC1845FTA
Q9 2SC945A - Replace with 512-KSC2383OTA
Q11 2SD712 (TO-92) Replace with 512-KSC2073TU
Q12 2SB682 (TO-92) Replace with 512-KSA940TU


2. Protection board has a total of 3 transistors.

Q1 & Q2 2SC945A Replace with 512-KSC2383OTA
Q3 2SC1885 Replace with 512-KSC2310YBU


3. We determined the following on the amp boards get replaced. Any others need replacing?

Q7 & Q8 2SA912 TO-92L Replace with 512-KSA1220AYS TO-126
Q9 & Q10 2SA726S Replace with 512-KSA992FBU
Q11 & Q12 2SC1885 TO-92L Replace with 512-KSC2690AYS TO-126


4. Phono transistors??? I scoured AK for 7800 posts and those that reference them and found no definitive info. Can you clarify please?

Part Checking

Any luck on part replacement verification of my choices offered?

As always... Much appreciated.

I have a 9800 i haven't even attempted to start work on. Following this thread with gusto, so much info, thanx.

I was working on it and ran into this:

gwh-119,gwh-120 on my .pdf
or
gwh-129,gwh-130 on spreadsheet


for the power amps?

where did you get your pdf?

If I may...


Please see the top of this bulletin. GWH-119,120 are KU model, GWH-129,130 S, S/G model.

markthefixer said:

I was working on it and ran into this:

gwh-119,gwh-120 on my .pdf
or
gwh-129,gwh-130 on spreadsheet


for the power amps?

where did you get your pdf?

Click to expand...

Yes, for the Power Amps.

My PDF is high res. Not sure where obtained from (AK Database?). I've had it for quite a while now. It is a complete and current SM to the best of my knowledge. I have used Rick before, but not for this particular manual, as it is very hi res and clear to read and seems complete.

Mine is the S/G model. Indicating that it is switchable voltage military model with a wood case. As Ed showed appropriately. The SM page 2 clarifies the various models.

Though it shows the Power Amp boards as GWH-125 and GWH-126 (which is for the S model) in the manual. It appears that per the bulletin Ed posted above that the SG model would be the same as the GWH-125 & 126 (S model), with the exception of the modification adding the caps.

Clear as mud?

I can take photos if it will help out.

The manual is confusing which isn't unusual! Mine shows the 119, 120 and 125, 126 boards, the bulletin refers to 3 variations with 129, 130 boards, and I've flipped back-and-forth comparing schematics and parts lists and I don't see a difference, but my eyeballs started getting fuzzy so I quit looking.

I have an SA-9800 that I should do something with haven't used it or powered it on in 5 years, it got swapped out with a Pioneer VSX-1015 AVR when I went multichannel in the living room, so I will be following this thread.

Thanks again Ed. I think that bulletin explains it pretty well. Bottom line is... They aren't much (if at all) different with the exception of those smaller cap changes/adds.

I await MTF's assessment.

Biting at the bit to get the parts on order and get this 9800 going. With the newly provided info about the Power Amp boards, any further on the overall parts assessment?

I am working on it, and am past the point where having the basic listing of all transistors per board (like the caps) would have advanced the cause.

markthefixer said:

I am working on it, and am past the point where having the basic listing of all transistors per board (like the caps) would have advanced the cause.

Click to expand...

Thanks Mark. I thought I was helping by putting it in this thread all in one place specific to MY 9800. None of that was copied and pasted, but done by hand one for one from my unit, and by scouring threads and making my best guess offering of what should be replaced where. Anything else I can do to advance the cause please let me know.