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Refurbishing a Technics SU-8080 - worth it and where are the gotchas?

Discussion in 'Solid State' started by Stevescivic, Nov 9, 2018.

  1. Stevescivic

    Stevescivic Active Member

    Messages:
    244
    Reposting here b/c I originally posted in the Pioneer forum asking the same exact question. Posted there b/c I am familiar with the folks that hang in there.

    I managed to score a Technics SU-8080 from a local eBay auction and much to my surprise it is in really good condition.

    I haven't fired it up yet but it looks 100% original and short of a few scuffs and the typical dust on the inside that the unit looks to be 100% original.

    A few issues I'll need to address:

    1. One of the positive terminal posts on the "remote" speaker out is broken. The red plastic likely was banged up against something and I'm not sure if the red knob itself can be replaced or if I need to buy a complete speaker terminal assembly. Are there aftermarket speaker terminals that would fit in place of the stock ones without any modding to the chassis?

    2. The power switch lever was bent when I bought it so I straightened it with some pliers but it doesn't "flip" or feel the same as the two levers in the middle of the receiver. I suspect that it is damaged and will require replacement. The toggle feeling of the switch feels wonky like as if the switch is sticky or has some drag and it likes to travel high up into the on position and yet when I flip to the off position that it feels like the switch won't go further down and hovers around the centre of the switches range of travel.

    3. The ground terminal on the back of the unit is bent. I tried to straighten this but broke the plastic piece off the terminal. The terminal will need to be replaced.

    Wondering how good is this integrated amplifier and whether or not it is worth recapping/rebuilding. I've rebuilt 2 Pioneer SX-1050's and both turned out perfectly and the SU-8080 looks pretty easy as well BUT... I'm wondering if someone here has a BOM for the part and whether or not this amplifier has any unobtanium parts that I need to be aware of. Caps are easy to identify and replace but I'm wondering about certain transistors, diodes, resistors and relays that should proactively replaced.

    I'm really impressed with the layout of this thing... it appears to be of very good quality and the circuit layout seems to be well thought out.

    Thanks,
     

     

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  2. drumbum

    drumbum Super Member

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    Any coastal Wal-mart will have them, or you can pay more at a dedicated tackle shop. Gold or silver body w/chartreuse head @ 7/8 oz is spanish mack candy, if they are around. Other color and weights work also.
     
    ivandezande and avionic like this.
  3. spark1

    spark1 Super Member

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    ??????
     
  4. drumbum

    drumbum Super Member

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    1,221
    The OP asked where are the gotchas.
     
  5. Stevescivic

    Stevescivic Active Member

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    244
    lol funny....
     
  6. avionic

    avionic " Black Knights " Subscriber

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    We just used plastic soda straws and a treble hook down on the Florida gulf coast for Spanish mack.:thumbsup: Same rig works real good Mahi Mahi fishing the tide line.
     

     

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  7. jcg1112

    jcg1112 Active Member

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    Well, damn now I want to go fishing. Double shad rig under a popping cork for specks. Two at a time is a bonus. .
     
  8. avionic

    avionic " Black Knights " Subscriber

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    Sand fleas- surf fishing for specks:thumbsup::biggrin:
     
  9. avionic

    avionic " Black Knights " Subscriber

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    43,863
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    Fort Dodge, Iowa
    https://www.vampirewire.com/product-page/bp-5
     
  10. avionic

    avionic " Black Knights " Subscriber

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    43,863
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    Upgrade...
    https://www.vampirewire.com/binding-posts
     
  11. Stevescivic

    Stevescivic Active Member

    Messages:
    244
    Avionic thanks for sharing those links. I was really hoping to not have to go through replacing the terminals on my amp since only one positive terminal was broken. Does anyone here have a spare terminal I could have? It looks like the individual terminals can be removed from the speaker terminal block.

    I managed to fix the power switch today by removing the front face panel and then carefully bending the switch straight and then resetting the plastic switch guide and lubricating thevswitch. It flips up and down like new again and more importantly that it actually turns the power circuit in and off.


    My next task is compiling a replacement component list so I can order them from mouser. Caps and output transistors are an obvious one but what about certain transistors and resistors and diodes?

    Thanks.
     

     

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  12. avionic

    avionic " Black Knights " Subscriber

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    A photo says a thousand words.
     
  13. slimecity

    slimecity Super Member

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    Location:
    New Zealand
    I've owned these amps twice.

    They are absolutely worth keeping. One of Technics best units IMO. Fully discrete, built like a tank, dual mono (right down to the power supply) and very easy to make sounding great with just a little bit of work.

    This unit gave me some of the best "technics sound" IMO - lively, punchy with great midrange.

    Im jealous, I would love to find another one to work on.
     
  14. Stevescivic

    Stevescivic Active Member

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    244
    @ Avionic - here is what I need a replacement for.

    @ Slimecity - yeah I wasn't keen on bidding on this unit but by FLUKE when I put in an offer that the seller agreed and I had it in my hands the very same day! The great thing is that this unit is all original with NO one molesting the insides so the first person to dive into it will be me and I trust my own work. Been working on deoxiting the controls and then once I get the parts BOM (hopefully with input from AK members) that I'll start the rebuild journey.
     

    Attached Files:

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  15. avionic

    avionic " Black Knights " Subscriber

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    Those are way different than Yamaha. Keep an eye on the bay.
     
  16. slimecity

    slimecity Super Member

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    New Zealand
    If it were my unit - I wouldnt bother - ie: if you will only run speakers from the "A" selection.

    However on the other hand, those Technics binding posts are a PITA as they dont take banana plugs. It will take a bit of trial and error looking up various replacements online and seeing what would fit IMO
     

     

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  17. Stevescivic

    Stevescivic Active Member

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    Yeah the speaker posts I don’t care much about since I don’t plan on running more than one pair of speakers anyways and there are other ways of running multiple speakers using the same speaker A terminals.

    Anyone have a replacement ground terminal? The guy that moved this amp also banged up the ground connection for the phono connection so I can’t even tighten the wire down for the record player ground.

    Looking at this amp it seems really easy to recap the unit and replace higher current output transistors but it is the other transistors/resistors/diodes that I am not sure of that should be replaced because of their age or inferior quality as compared to modern components.
     
  18. avionic

    avionic " Black Knights " Subscriber

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    or....https://www.mouser.com/ProductDetail/Johnson-Cinch-Connectivity-Solutions/111-2223-001?qs=sGAEpiMZZMtW7Xd10NdmuPFszllTf2imAFlK6xO9AfA=

    https://www.mouser.com/datasheet/2/643/pi-CCS-JOHN-111-2223-001-1289774.pdf
     
  19. ryuuoh

    ryuuoh FFXIV Summoner Subscriber

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    slimecity likes this.
  20. Stevescivic

    Stevescivic Active Member

    Messages:
    244
    ah yes... ryuuoh and slimecity... I was looking around AK and found some threads on your rebuild and past inputs to others...

    So I did the foolish thing by not hooking the amp up to a DBT and fired her up. Figured that since the insides weren't burnt or had damage and was immaculate that I didn't think it would fry by turning it on.... ran great for about 20 minutes and then when I powered it off and back on the right channel started crackling which I suspect is due to a bad speaker/protection relay. I'm assuming it is a standard 12 or 24 volt relay.

    @ ryuuoh I saw a thread here (I think it was yours) that recapping the amp is a PITA? Seems SUPER easy actually compared to some of Pioneer's fluoroscan receivers of the early 80's. The EQ/tone board looks like it's held in with a few screws and I could just flip the board over and replace the caps. The protection board I can see being a nuisance but since everything is exposed underneath the amp that couldn't I just move the EQ board out of the way, desolder from underneath the amp and then replace components and reassemble? Did you just replace the caps and the relay or did you also replace some transistors/diodes/resistors that were failure prone as well? You wouldn't happen to have your original BOM would you? I guess what I'm trying to figure out is what else needs to be ordered to rebuild this thing to its former glory. Flip switches and pots are extremely clean now and I just have to desolder the push buttons on the eq boards to take them apart to clean them when I recap the amp.

    When the SU-8080 was playing I was really really impressed by how good it sounded. It had a sense of airiness to it that I thought was neat. If it sounds amazing in its current state I can't even imagine what it would sound like once new electrolytics are put in along with new output transistors + speaker relay...

    Many thanks to everyone here! Going to a be a fun project :)
     
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