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SAE Mark Four C replacement Pwr transistors

Discussion in 'Solid State' started by hgriffin1, Aug 1, 2013.

  1. hgriffin1

    hgriffin1 New Member

    Messages:
    6
    Location:
    CT
    Hello,

    Can anyone recommend a replacement for SAE 701 power transistors in the Mark Four C power amplifier? I checked the SAE refernence chart on Wardsweb.org and there is nothing showing for these devices... It also appears the the replacements for the SAE 202 and SAE 11 devices are now obsolete...

    Thanks,
    Hugh
     

     

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  2. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
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    What do the ACTUAL transistors say on them???
     
  3. hgriffin1

    hgriffin1 New Member

    Messages:
    6
    Location:
    CT
    They are imprinted "SAE 701". The other imprinted numbers are: 466 7325 (printed with red ink) & 466 7330 (printed in black ink) I assume the color designates NPN and PNP.

    "SAE 11" M(otorola) 0063 7439 (in red ink) M(otorola) 0063 7426 (in black ink)
    "SAE 202" M(otorola) 7413 (in red ink) M(otorola) 7339 (in black ink)
     
  4. hgriffin1

    hgriffin1 New Member

    Messages:
    6
    Location:
    CT
    BTW they are all T0-3 cases
     
  5. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,889
    Location:
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    Did you try contacting him directly? He may have data that is not on the site.

    The On-Semi mj21193 and 94 should be heavy duty enough to handle to handle the Mark 4C. Physically check the polarity on them then match the new ones to them.

    What are the the 11 and 202 devices?? I don't see them listed in the tables on wardsweb

    On the #'s you gave for the "11" the 1st 3 should be the part # and the last four are the date manufactured. And for the 202 they are the date codes. ie:7439 = 1974 39th week

    Please take some pictures of the Mark4C, 11, & 202 output's that are clear and legible. Might be able to discern something from them. Also some specs for all 3.

    Thanks

    Larry
     
    Last edited: Aug 2, 2013
  6. elnaldo

    elnaldo Addicted Member

    Messages:
    7,382
    Location:
    Buenos Aires GMT-3
    Do you have a schematic? The schematics I've seen from SAE were very clear about this things.
     

     

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  7. hgriffin1

    hgriffin1 New Member

    Messages:
    6
    Location:
    CT
    Pics of Output Transistors

    Here are the pictures of the output transistors. I don't have a full schematic. Just a block diagram of the amp showing the configuration of the outputs. No values for these components unfortunately.
     

    Attached Files:

  8. llwhtt

    llwhtt Super Member

    Messages:
    1,488
    Location:
    SoCal
    Are you working on a 4C or 4D? The schematic you posted is for a 4D which is a completely different circuit from the 4C. Can you post a picture of the PCBs? If it is truly a 4C then you will want 2N3773 output devices. The 4D uses Darlington output devices.

    Craig
     
  9. hgriffin1

    hgriffin1 New Member

    Messages:
    6
    Location:
    CT
    PCB pics

    Here's a pic of one of the boards, and internal shot and the face plate with the model name...
     

    Attached Files:

  10. electrohifi

    electrohifi Active Member

    Messages:
    122
    Location:
    Ontario Canada

    those look like old motorola devices, you need to cut a dead one open and post a pic so we can see if it is hometaxial or not. those tops pop off quite easy with decent size wire cutters just go hard and slow so you dont wreck the insides.
     
  11. petehall347

    petehall347 the brandy coffee man Subscriber

    Messages:
    28,084
    Location:
    uk.. the middle bit
    here you go .. i see one reference "0063"..i will leave it up you to see if the others are there ..
     

     

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  12. llwhtt

    llwhtt Super Member

    Messages:
    1,488
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    Go to "SAE Talk" for the schematic in the files section, you'll have to join but no big deal. Mouser has the 2N3773s and the 2N4036s in the differential if needed. Check your DC offset and swap the socketed 2N4036s around if needed. Also check the big carbon comp resistors (2.7K and 1.5K) they are usually out of tol. Might want replace all of the axial electrolytic while you are at it, Mouser carries Nichicons, that what I use.

    Once you are on the SAE Talk site you'll see many different "Marks", your amplifier may or may not match the schematic exactly. I've been thru a bunch of the Mark IIIs and IVs, not many were exact matches. I chased the true output devices for hours and Mark at Absolute Sounds had answer, 2N3773s. He was one James Bongiorno's "designated" repair guys. This amplifier is before the Bongiorno era though, the "D" was his. You can tell by the dual diffs in the front end.

    Craig
     
  13. sregor

    sregor AK Subscriber Subscriber

    Messages:
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    Location:
    Mass
    At wardsweb the 11-0063 is listed as MJ802 (also SAE 101) The 202 is also listed as 11-0069 and is MJ4502 ,
     
  14. hgriffin1

    hgriffin1 New Member

    Messages:
    6
    Location:
    CT
    I DL'd the schematic from SAE Talk. Thanks! Yes, the output devices are different on mine. The schematic shows SAE 601's... I will be ordering some 2N3773's. Already have the caps on order. The comp resistors were out of tolerance as well so they will be replaced. Thanks for all the help!
     
  15. RoveronMars

    RoveronMars New Member

    Messages:
    2
    Hello. I found this thread a little bit confusing. I am trying to find replacements for the SAE 701 transistors. The thread started off promisingly referring to SAE 701 but subsequently changed to SAE 601 for which supposedly is the 2N3773 equivalent. I am hoping someone can tell me the equivalent for the SAE 701. I am a bit curious as to why on the SAE Mark 31 power amp, the SAE 701 are green inked on the "b" channel versus blacked inked on the "a" channel. All of the SAE 701's are NPN BJT type. I am currently recapping this power amplifier and would appreciate any comments as well as answers. Thanks, Roveronmars
     
  16. sregor

    sregor AK Subscriber Subscriber

    Messages:
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  17. llwhtt

    llwhtt Super Member

    Messages:
    1,488
    Location:
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    My 4C schematic has MJ802/4502, SAE101/202, SAE0063/0069 for the drivers and SAE601 for the outputs. My personal 4C has those drivers with SAE701 outputs. When I rebuilt my MKXXXIM (mono) it originally had SAE601 outputs and I used the 2N3773s as replacements. All of these transistors are relatively slow as are all of the ON Semi TO-3s so shouldn't be a problem to use the latest and greatest MJ211xx types.

    Just going thru my SAE schematics and found the schematic that covers the MKIIB, MKIII, MKIIIA and MKIVB. In the notes section it says SAE601 was 2N3773.

    Craig
     
    Last edited: Dec 8, 2018 at 7:29 PM
  18. RoveronMars

    RoveronMars New Member

    Messages:
    2
    My thanks to sregor and llwhtt for their replies. Right now I am in the midst of writing my synopsis of the problems found with the SAE Mark XXXI power amp that I owned. I will include results from the PEAK Atlas DC Pro testing of the output transistors and hopefully will resolve whether it should be 2N3773 or MJ21194. This synopsis I hope to include in this thread tomorrow night. RoveronMars
     

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