Starbender
Gathering dust...
Look what I found! & SX-939 Restoration attempt;
But ofc it has problems
But ofc it has problems
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Look what I found!
- Thread starter Starbender
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Starbender
Gathering dust...
At the warehouse :thmbsp:
Very Nice. Check out these two threads that pertain to the 939.
1.) http://www.audiokarma.org/forums/showthread.php?t=494501
2.) http://www.audiokarma.org/forums/showthread.php?t=512271
After fixing the problems and getting it running at a baseline condition, THEN do the recap and retransistor.
The usual SUSPECTS will get pre-emptively replaced. A.) All 2sa725 and 726 on ALL boards that have them. B.) 2sc1451's on the amplifier board.
A lot of stuff that gets replaced on the 939 is also the same on a 1010 provided the board is the same part #. If you can't find it for the 939 in the threads, look and see if the 1010 has it.
The 1st thread should have all the part #'s you'll need for recap and transistors. The complete cap list is there. Later in the thread is a partial transistor list. It should be enough to get you going. Any questions, ASK!
Larry
1.) http://www.audiokarma.org/forums/showthread.php?t=494501
2.) http://www.audiokarma.org/forums/showthread.php?t=512271
After fixing the problems and getting it running at a baseline condition, THEN do the recap and retransistor.
The usual SUSPECTS will get pre-emptively replaced. A.) All 2sa725 and 726 on ALL boards that have them. B.) 2sc1451's on the amplifier board.
A lot of stuff that gets replaced on the 939 is also the same on a 1010 provided the board is the same part #. If you can't find it for the 939 in the threads, look and see if the 1010 has it.
The 1st thread should have all the part #'s you'll need for recap and transistors. The complete cap list is there. Later in the thread is a partial transistor list. It should be enough to get you going. Any questions, ASK!
Larry
Starbender
Gathering dust...
Thanks Larry. In fact I already read & took notes from your SX939 thread. Very impressive :thmbsp:. I'm making a complete problem list. Year ago I fixed&recap my friend's sx828. It was a lot of fun & headache
Starbender
Gathering dust...
A few internal pics.
Volume pot is broken. Two dial lamp is burned. There is no pre-power bars. However there is sound?! When I turn on tone controls and increase bass or treble a little, it goes to protection. Seems like previous owner tried to steal a signal internally. But he steal the signal from the tone board! Desoldered this already. Internally it looks ok. I will do a full recap and replace necessary transistors and diodes. :thmbsp:
Volume pot is broken. Two dial lamp is burned. There is no pre-power bars. However there is sound?! When I turn on tone controls and increase bass or treble a little, it goes to protection. Seems like previous owner tried to steal a signal internally. But he steal the signal from the tone board! Desoldered this already. Internally it looks ok. I will do a full recap and replace necessary transistors and diodes. :thmbsp:
Attachments
Planing on parting it out?Or party it out?
Answered...:
acv-134 pot, 737, 838, 939, 1010 donors
I also hope it gets up and running, considering its one of those rare models with the optional work light:
Attachments
tsd71
RIP Tom Petty
I also hope it gets up and running, considering its one of those rare models with the optional work light:
Quite rare I've never seen one before. You got a gem there. Good luck resurrecting it !
Check the wiring from and to the relay. Also check the wiring from and to the PRE-OUT/MAIN-IN RCA's. Sounds like the P.O. jumpered the Pre/Main.
Set the Zero Voltage then Set BIAS to 25mV vs 50mV and see if you can run the tone controls up and down with out tripping the protection.
I absolutely hate it when a hacker gets inside and screws with the wiring on these. I had one hell of a time with the Low/HIGH/-20dB switch gang.
Larry
Set the Zero Voltage then Set BIAS to 25mV vs 50mV and see if you can run the tone controls up and down with out tripping the protection.
I absolutely hate it when a hacker gets inside and screws with the wiring on these. I had one hell of a time with the Low/HIGH/-20dB switch gang.
Larry
Starbender
Gathering dust...
Removed hacker cable from awg-027 to pre jumper leads. Made a proper jumper for pre-power. Now when I turn on tone controls it does not trigger protection. But if I increase bass&treble to full boost, it goes to protection.
I have lots of caps&diodes. I'll have to make a list for missing parts and transistors.
Update: Low,High&-20dB switchs are working properly now.
I have lots of caps&diodes. I'll have to make a list for missing parts and transistors.
Update: Low,High&-20dB switchs are working properly now.
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Starbender
Gathering dust...
Thank you Mark. Hopefully a fellow AK'er probably have acv-134 :thmbsp:
Starbender
Gathering dust...
Finally I have all the necessary parts to fix this beauty :yes:
Special thanks to 'Unclebort' for his kind support. He sent me volume pot&knob for free!
Thank you so much :thmbsp:
At first AWR-052 power supply board has been recapped. All transistors&diodes replaced with the subs.
Caps;
C11 47UF 63V
C12 47UF 50V
C13 470UF 80V
C14 470UF 80V
C15 100UF 63V
C16 100UF 63V
C17 47UF 16V
C18 47UF 16V
C21 47UF 50V
C22 2200UF 10V
C23 220UF 16V
C24 1000UF 35V
Transistors;
Q1 2SD313 KSC2073TU
Q2 2SC1318 KSC2690AYS
Q3 2SC1318 KSC2690AYS
Q4 2SB507 KSA940TU
Q5 2SA720 KSA1220AYS
Q6 2SD313 KSC2073TU
Diodes;
D1 SIB01-04 1N4004
D2 SIB01-04 1N4004
D3 SIB01-04 1N4004
D4 SIB01-04 1N4004
D5 SR3AM8 1N5404
D6 SR3AM8 1N5404
D7 SR3AM8 1N5404
D8 SR3AM8 1N5404
D9 1S1885 1N4004
D10 1S1885 1N4004
D11 1S1885 1N4004
D12 WZ-130 1N5243B
D13 WZ-130 1N5243B
D14 WZ-140 1N5244B
Tested with dbt. All pin voltage readings matchs.
Soldered flyback diode on pin 9-10 at the protection circuit. AWM-062 Protection board recapped.
C1 .22UF 10V
C2 .22UF 10V
C3 330UF 6V
C4 330UF 6V
C5 4.7UF 25V
C6 100UF 16V
So far only Q7 2SC1384 replaced. Tested and jumped to AWG-027. Fully recapped&replaced transistors with the subs.
C1 .33UF 25V
C2 .33UF 25V
C7 100UF 10V
C8 100UF 10V
C13 2.2UF 25V
C14 2.2UF 25V
C15 4.7UF 35V
C16 4.7UF 35V
C23 4.7UF 25V
C24 4.7UF 25V
C25 10UF 16V
C26 10UF 16V
C29 100UF 10V
C30 100UF 10V
C31 4.7UF 35V
C32 4.7UF 35V
C39 4.7UF 25V
C40 4.7UF 25V
C41 10UF 16V
C42 10UF 16V
C45 100UF 10V
C46 100UF 10V
C47 2.2UF 25V
C48 2.2UF 25V
C49 100UF 16V
C50 100UF 16V
C51 100UF 16V
C52 100UF 16V
Q1 2SA725 KSA992FBU
Q2 2SA725 KSA992FBU
Q3 2SC1312 KSC1845EBU
Q4 2SC1312 KSC1845EBU
Q5 2SC1312 KSC1845EBU
Q6 2SC1312 KSC1845EBU
Q7 2SC1312 KSC1845EBU
Q8 2SC1312 KSC1845EBU
Now, tone controls doesnt kick protection.
So far everything goes well
Next step, Volume pot replacement & Power amp.
Special thanks to 'Unclebort' for his kind support. He sent me volume pot&knob for free!
Thank you so much :thmbsp:
At first AWR-052 power supply board has been recapped. All transistors&diodes replaced with the subs.
Caps;
C11 47UF 63V
C12 47UF 50V
C13 470UF 80V
C14 470UF 80V
C15 100UF 63V
C16 100UF 63V
C17 47UF 16V
C18 47UF 16V
C21 47UF 50V
C22 2200UF 10V
C23 220UF 16V
C24 1000UF 35V
Transistors;
Q1 2SD313 KSC2073TU
Q2 2SC1318 KSC2690AYS
Q3 2SC1318 KSC2690AYS
Q4 2SB507 KSA940TU
Q5 2SA720 KSA1220AYS
Q6 2SD313 KSC2073TU
Diodes;
D1 SIB01-04 1N4004
D2 SIB01-04 1N4004
D3 SIB01-04 1N4004
D4 SIB01-04 1N4004
D5 SR3AM8 1N5404
D6 SR3AM8 1N5404
D7 SR3AM8 1N5404
D8 SR3AM8 1N5404
D9 1S1885 1N4004
D10 1S1885 1N4004
D11 1S1885 1N4004
D12 WZ-130 1N5243B
D13 WZ-130 1N5243B
D14 WZ-140 1N5244B
Tested with dbt. All pin voltage readings matchs.
Soldered flyback diode on pin 9-10 at the protection circuit. AWM-062 Protection board recapped.
C1 .22UF 10V
C2 .22UF 10V
C3 330UF 6V
C4 330UF 6V
C5 4.7UF 25V
C6 100UF 16V
So far only Q7 2SC1384 replaced. Tested and jumped to AWG-027. Fully recapped&replaced transistors with the subs.
C1 .33UF 25V
C2 .33UF 25V
C7 100UF 10V
C8 100UF 10V
C13 2.2UF 25V
C14 2.2UF 25V
C15 4.7UF 35V
C16 4.7UF 35V
C23 4.7UF 25V
C24 4.7UF 25V
C25 10UF 16V
C26 10UF 16V
C29 100UF 10V
C30 100UF 10V
C31 4.7UF 35V
C32 4.7UF 35V
C39 4.7UF 25V
C40 4.7UF 25V
C41 10UF 16V
C42 10UF 16V
C45 100UF 10V
C46 100UF 10V
C47 2.2UF 25V
C48 2.2UF 25V
C49 100UF 16V
C50 100UF 16V
C51 100UF 16V
C52 100UF 16V
Q1 2SA725 KSA992FBU
Q2 2SA725 KSA992FBU
Q3 2SC1312 KSC1845EBU
Q4 2SC1312 KSC1845EBU
Q5 2SC1312 KSC1845EBU
Q6 2SC1312 KSC1845EBU
Q7 2SC1312 KSC1845EBU
Q8 2SC1312 KSC1845EBU
Now, tone controls doesnt kick protection.
So far everything goes well
Next step, Volume pot replacement & Power amp.
Attachments
Starbender
Gathering dust...
Just noticed, power supply transistors gets hot in few minutes.
Pin readings;
Pin 2 +7.5V
Pin 4 +13V
Pin 5 +33.5V
Pin 6 +47.5V
Pin 8 +25V
Pin 9 -43V
Pin 10 -13V
Pin 11 -25V
According to SM, voltages are ok. What could be the cause of overheating?
Or is this normal?
Pin readings;
Pin 2 +7.5V
Pin 4 +13V
Pin 5 +33.5V
Pin 6 +47.5V
Pin 8 +25V
Pin 9 -43V
Pin 10 -13V
Pin 11 -25V
According to SM, voltages are ok. What could be the cause of overheating?
Or is this normal?
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It's Normal. The new transistors are heavier duty and dissipate more heat but they do it more in the middle of the SOA(Safe Operating Area), whereas the originals made a lot too but right at the ragged edge of the SOA. That's the reason for the heatsinks. Just make sure when you close it up, there are no blocked access holes or vents, and never stack anything on the 939. It's not as sensitive to heat as the 1010, but it's close to it.
On the protection board. The diode "ON THE BOARD" closest to pin 12, change it to a 1n4004. I can't remember if it's because it's a heavier duty part or what but MARK the Fixer recommended it. I put it in on my 939 and 737. (3rd picture, diode at the top of the board on the left.)
Larry
On the protection board. The diode "ON THE BOARD" closest to pin 12, change it to a 1n4004. I can't remember if it's because it's a heavier duty part or what but MARK the Fixer recommended it. I put it in on my 939 and 737. (3rd picture, diode at the top of the board on the left.)
Larry
