Pioneer SPEC-4 repair and restoration thread!

Discussion in 'Pioneer Audio' started by mattsd, Jun 10, 2012.

  1. mattsd

    mattsd AK Subscriber Subscriber

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    As a compliment to my SPEC-1 thread, I am also doing a SPEC-4 for the same member, r11cool and this will have a full restore done to it as well. So far I have found that almost every transistor on the right channel board is either shorted or open, including the outputs along with three or four toasted resistors. :yikes: So, stayed tuned!
     

     

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  2. omri617

    omri617 Super Member

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    great job , will be watching this thread ,
    the Spec 4 was working even though these issues??
     
  3. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

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    no way.....
     
  4. mattsd

    mattsd AK Subscriber Subscriber

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    No, it quit working with a crackle pop and magic smoke according to the owner, and no wonder. The list of bad components is scary, here is the final tally:

    Q6: 2SA733, shorted every way
    Q7: 2SC945, open from base to emitter
    Q8: 2SC1904, shorted every way
    Q9: 2SA899, open from base to emitter and a abnormally high reading from base to collector
    Q11: 2SB628, shorted every way
    Q13: 2SC945, open from base to emitter and shorted from base to collector
    Q14: 2SA733, shorted every way

    All the outputs are shorted or open in someway.

    R24, 28, 34, and 36 are all burnt open with high (millions) or infinite ohms, two of them literally melted.

    Amazingly, Q10 survived, though I'm replacing it anyway. All the diodes are fine and the emitter resistors are good too. :scratch2: The damage is still the worst I have ever seen though, this thing really blew up.
     
    Last edited: Jun 11, 2012
  5. tsd71

    tsd71 RIP Tom Petty Subscriber

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    Good luck with this one Matt
     
  6. mattsd

    mattsd AK Subscriber Subscriber

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    Pioneer SPEC-4 recap list

    Thanks Tim. Here is the recap list for the SPEC-4.

    Pioneer SPEC-4 recap list (edit 2/15/18 for some part number changes)

    Meter Amp Board (AWM-113) (Q8 and 9 should be gain matched) (Check board revision number, the A version has C1 as a 100uF 25v CEA cap and C11 as a 100uF 80v CEA cap)

    AWM-113: C1: 220uF 10v CEA: 647-UPW1A221MED 220uF 10v
    AWM-113: C2: 2.2uF 50v CEANL: 647-UKL1H2R2KDDANA 2.2uF 50v
    AWM-113: C3: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
    AWM-113: C4: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
    AWM-113: C7: 3.3uF 63v CEA: 647-UPW2A3R3MDD 3.3uF 100v
    AWM-113: C8: 3.3uF 63v CEA: 647-UPW2A3R3MDD 3.3uF 100v
    AWM-113: C11: 47uF 80v CEA: 647-UPW2A470MPD6 47uF 100v
    AWM-113: C12: 47uF 80v CEA: 647-UPW2A470MPD6 47uF 100v
    AWM-113: C13: 330uF 100v CEA: 647-UPW2A331MHD 330uF 100v
    AWM-113: C14: 330uF 100v CEA: 647-UPW2A331MHD 330uF 100v
    AWM-113: C16: 33uF 25v CEA: 647-UPW1V330MDD 33uF 35v
    AWM-113: C17: 47uF 16v CEA: 647-UPW1V470MED 47uF 35v
    AWM-113: C18: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
    AWM-113: C19: 470uF 6.3v CEA: 647-UPW1A471MPD 470uF 10v
    AWM-113: C24: 2.2uF 50v CEA: 647-UPW1H2R2MDD 2.2uF 50v
    AWM-113: C25: 2.2uF 50v CEA: 647-UPW1H2R2MDD 2.2uF 50v
    AWM-113: C26: 2.2uF 50v CEA: 647-UPW1H2R2MDD 2.2uF 50v
    AWM-113: C27: 2.2uF 50v CEA: 647-UPW1H2R2MDD 2.2uF 50v
    AWM-113: C28: 3.3uF 50v CEA: 647-UPW1H3R3MDD 3.3uF 50v
    AWM-113: C29: 3.3uF 50v CEA: 647-UPW1H3R3MDD 3.3uF 50v
    AWM-113: C30: 47uF 16v CEA: 647-UPW1V470MED 47uF 35v
    AWM-113: C31: 47uF 16v CEA: 647-UPW1V470MED 47uF 35v
    AWM-113: C32: 47uF 25v CEA: 647-UPW1V470MED 47uF 35v
    AWM-113: C33: 47uF 25v CEA: 647-UPW1V470MED 47uF 35v

    Q8: 2SC945: 512-KSC945CYTA
    Q9: 2SC945: 512-KSC945CYTA
    Q11: 2SC945: 512-KSC2383YTA
    Q12: 2SC945: 512-KSC2383YTA
    Q13: 2SC1384: 512-KSC2690AYS

    If board is the "A" revision, then:

    Q1: 100uF 25v CEA: 647-UPW1V101MPD 100uF 35v
    Q11: 100uF 80v CEA: 647-UPW2A101MHD 100uF 100v

    BOM List, put the 647-UPW2A470MPD6 to 1 and add these two lines into the main BOM list:

    647-UPW2A101MHD | 1
    647-UPW1V101MPD | 1

    Power Amp Board (AWH-065) (Times 2) (Q2 and 3 should be gain matched)

    AWH-065: C1: 100uF 80v CEA: 647-UPW2A101MHD 100uF 100v
    AWH-065: C2: 100uF 80v CEA: 647-UPW2A101MHD 100uF 100v
    AWH-065: C3: 100uF 80v CEA: 647-UPW2A101MHD 100uF 100v
    AWH-065: C4: 100uF 80v CEA: 647-UPW2A101MHD 100uF 100v
    AWH-065: C24: .22uF 10v CSSA: 80-F612JF224J063A .22uF 63v

    Q2: 2SC1775: 512-KSC1845FTA
    Q3: 2SC1775: 512-KSC1845FTA
    Q12: 2SC869: 512-KSC1845FTA

    VR1: 470 ohm multi offset: 652-3296P-1-501LF 25 turn
    VR2: 470 ohm single bias: 652-3386H-1-501LF 1 turn

    Only replace these VR's below if you have the equipment to re-adjust the power limiter after replacement:

    VR3: 100 ohm single: 652-3386H-1-101LF
    VR4: 100 ohm single: 652-3386H-1-101LF

    S1: MU2U 48VDC relay: 653-MY2-02-DC48

    BOM List:

    647-UKL1H2R2KDDANA | 1
    647-UPW1H2R2MDD | 4
    647-UPW1A221MED | 1
    647-UPW1A471MPD | 4
    647-UPW2A3R3MDD | 2
    647-UPW2A470MPD6 | 2
    647-UPW2A331MHD | 2
    647-UPW1V330MDD | 1
    647-UPW1V470MED | 5
    647-UPW1H3R3MDD | 2
    647-UPW2A470MPD6 | 1
    647-UPW2A101MHD | 8
    80-F612JF224J063A | 2
    512-KSC1845FTA | 6
    512-KSC2383YTA | 2
    512-KSC945CYTA | 2
    512-KSC2690AYS | 1
    653-MY2-02-DC48 | 2
    652-3386H-1-501LF | 2
    652-3296P-1-501LF | 2

    And the additional list for the blown components on the right amp board:

    Power Amp Board (AWH-065)

    Q6: 2SA733: 512-KSA1013YBU
    Q7: 2SC945: 512-KSC945CYTA
    Q8: 2SC1904: 512-KSC3503DSTU
    Q9: 2SA899: 512-KSA1381ESTU
    Q10: 2SD608: 512-KSC2073TU
    Q11: 2SB628: 512-KSA940TU
    Q13: 2SC945: 512-KSC945CYTA
    Q14: 2SA733: 512-KSA1013YBU

    R24: 22 ohm 1/4w: 660-MF1/4DCT52R22R0F 22 ohm 1/4w
    R28: 200 ohm 1/2w: 660-MF1/2CCT52R2000F 200 ohm 1/2w
    R34: 220 ohm 1/2w: 660-MF1/2LCT52R221J 220 ohm 1/2w
    R36: 100 ohm 1/2w: 660-MF1/2DCT52R1000F 100 ohm 1/2w

    The outputs

    2SD424: 863-MJ21194G
    2SB554: 863-MJ21193G

    BOM list

    512-KSA1013YBU | 2
    512-KSC945CYTA | 2
    512-KSC3503DSTU | 1
    512-KSA1381ESTU | 1
    512-KSC2073TU | 1
    512-KSA940TU | 1
    863-MJ21194G | 4
    863-MJ21193G | 4
    660-MF1/4DCT52R22R0F | 1
    660-MF1/2CCT52R2000F | 1
    660-MF1/2LCT52R221J | 1
    660-MF1/2DCT52R1000F | 1

    All parts were confirmed to be in stock at the time of this post.
     
    Last edited: Feb 14, 2018
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  7. Ed in Tx

    Ed in Tx Super Member

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    Sounds exactly like what happened to a channel in one of my Spec-4s last November. I attribute the failure to multiple cracked, weak, stressed solder connections. Not only were these found on the amplifier board that failed, but the other amp board, the meter amp board, both rectifier boards and and even the fuse holder board! Went through all boards of both amplifiers. Amazing to me they worked up to that point considering how many bad solder connections I found.


    [​IMG]
     
  8. mattsd

    mattsd AK Subscriber Subscriber

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    Yes, I have been finding those as well. I plan on going over every inch of this thing and checking for bad joints, components and the like.
     
  9. omri617

    omri617 Super Member

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    how long normally takes repair and restoration like this for you to get done?
     
  10. dr*audio

    dr*audio Fish fingers and custard!

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    You should replace the speaker relays at this time, too. The originals are no longer available and I could not find a plug in replacement. I found a Panasonic relay with 10A contacts that I will be using, but unfortunately the part is discontinued. I ordered a few from Online Components. It is not a plug in replacement. There is a place on the pcb for a second relay. What I am going to do is use some of the holes for each relay. You have to rotate the relay by 90 degrees so the coil pins are at the end of the board nearest the output. Then you have to drill 2 holes in the board for the end pins of the relay, and cut the traces on the board, and add jumpers from the relay to the correct connections on the board. I will take pictures of the mod and post them here. It's going to be later this week.
     
  11. markthefixer

    markthefixer On Hiatus, dealing with Dad's estate full time Subscriber

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    Warren, how is the height of the replacement??

    I have some Spec-4's that need them too (shipping damage no less)
     

     

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  12. dr*audio

    dr*audio Fish fingers and custard!

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  13. dr*audio

    dr*audio Fish fingers and custard!

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    Here's how I replaced the relays:
    First, remove the old relay. Now you can see there is a spot on the board for a second unused relay. If you line up the new relay along side the holes, you will see that 4 of the six holes line up. Hooray! Less work for me!
    [​IMG]
    You have to drill 2 new holes. Also the original holes have to be enlarged a bit because the new relay has fatter pins.
    [​IMG]
    Now cut the traces in the places shown.
    [​IMG]
    Solder the new relay in and install the jumpers as shown.
    [​IMG]
    And here's the new relay, looking like it belongs there!
    [​IMG]
     
  14. EchoWars

    EchoWars Hiding in Honduras

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    Omron's G4W series looks to be the same, and are rated at 15A as opposes to the 10A of the Panasonic (the Panasonic are probably just more conservatively rated), except that Omron does not make a 48Vdc variation. The Q7 regulator would have to be redone to supply 24V instead of 48V. Do-able, but a pain. Digikey has over 1000 of the Z2245-ND (Omron #G4W-2212P-US-TV5-HP-DC24) relays in stock. If there was an easy way to run the two relays in series...
     
  15. mattsd

    mattsd AK Subscriber Subscriber

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    And here are some photos!

    Right amp board before, you can see the burned out resistors from browned heat wraps over them.

    [​IMG]

    Left amp board

    [​IMG]

    And some after photos!

    Right amp board

    [​IMG]

    Left amp board

    [​IMG]

    I had to customize the boards a little to fit the new relay in. The photos below are of the right amp board.

    I first checked the fit and drilled some new holes using a 1/16" bit, I was a little off on the last two on the far right, they should have been even with the others

    [​IMG]

    Soldering it in, I scraped some the green coating off of the trace around where the new holes were so the solder would stick and soldered it in. The output wire that goes to the speaker terminal needs to be moved from pin 12 to pin 13, also needed are two jumpers, one, the green wire, jumps the 48VDC for the relay over to the new relay position and two, the bare wire jumper, connects pin 13 to pin 12 so the meter drive circuit (pin 10) works, as pin 10 is directly connected to pin 12 but not pin 13.

    [​IMG]

    And it's all together again!

    [​IMG]

    All 8 outputs have been replaced as well. I powered it up on a DBT after each amp board and the relays worked perfectly, glorious music greeted me when I tried it for the first time. :banana: The offset was rock steady after being on for about 5-10 minutes and even when first powered on it doesn't jump around, it just slowly drops until it reaches the steady point.

    More to follow!
     
    Last edited: Jul 6, 2012
  16. Ed in Tx

    Ed in Tx Super Member

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    The resistors that fried in mine...

    [​IMG]

    That one on the left appears to have gotten the hottest in both of our amps.
     

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  17. EchoWars

    EchoWars Hiding in Honduras

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    Replace the burnt resistors with flameproof and you can leave the weave fabric stuff off (it's only there to limit oxygen to the resistor so it can't openly burn).
     
  18. mattsd

    mattsd AK Subscriber Subscriber

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    Thanks Glenn, I will remember that.

    And here is the meter amp board!

    Before

    [​IMG]

    After

    [​IMG]

    Next up, filter caps!
     
    Last edited: Jul 6, 2012
  19. mattsd

    mattsd AK Subscriber Subscriber

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    Here are some before photos of the filter caps.

    [​IMG]

    [​IMG]

    Also, here is a photo of the relay clearance on the left amp board.

    [​IMG]

    After photos coming up!
     
    Last edited: Jul 6, 2012
  20. Ed in Tx

    Ed in Tx Super Member

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    Suggestion: Please reduce the picture size!
     

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