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Replacing Concert Head Unit with aftermarket

Discussion in 'A4/S4 forum(B5 Chassis)' started by Blue_Thunder, Jul 19, 2011.

  1. Blue_Thunder
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    Blue_Thunder Active Member

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    [Jul 19, 2011]
    Hi guys, after some fairly straight forward advice.

    If I buy an aftermarket Head Unit to replace my gash volume Concert (non-Bose), will it work straight out of the box or will I need loom adaptors, etc?
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  3. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 19, 2011]
    I'd suspect your car will still have half amplified speakers, so it would be plug and play (but you'd only get sound from the front speakers) or use a PC9-401 in between the stereo and the cars harness. oh and an FP-05-00 fascia trim (maybe a PC5-90 antenna adaptor). And your all set :salute:
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  4. LeeT
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    LeeT Member

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    [Jul 19, 2011]
    On the same subject, how is the standard head unit removed?
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  5. S4_dan
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    S4_dan Fire up the Quattro!

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    [Jul 19, 2011]
    @Blue_Thunder....What car/model do you have? (also, fab film is Blue Thunder!)

    @LeeT....there are 2 small holes about 10mm long at each bottom corner of the concert HU. Use two keys, similar to what the Sony HU requires to remove, and pull stereo out.
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  6. LeeT
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    LeeT Member

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    [Jul 19, 2011]
    excellent, thanks mate
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  7. Blue_Thunder
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    Blue_Thunder Active Member

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    [Jul 20, 2011]
    It's a 98 S4. Looking on eBay, a few sellers seem to suggest the PC9-401 works for Bose models. Will this defo work for non-Bose as well?
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  8. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 20, 2011]
    so long as its a "rear only" cable, it'll work just fine, bose or otherwise.

    Personally, i'd rewire the rear speakers into the head unit, or properly amp the whole thing.

    The OE amp is pretty junk.
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  9. Blue_Thunder
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    Blue_Thunder Active Member

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    [Jul 20, 2011]
    Mine's a saloon, so I don't think there is a separate amp for the rear speakers?

    With that being the case, are the rear speakers in a saloon already wired into the HU?

    Sorry for all the numpty questions. My audio knowledge is very very poor!
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  10. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 20, 2011]
    simple way to check. pull the HU out and count the number of wires in the speaker connection (2nd 8wy connector down to the right of the fuse).

    Number of wires/System
    0/2=BOSE
    4=1/2 amp rear, none BOSE
    8=standard speakers no amp.

    Piccy shows half amplified (rear amp only), the "Line Out is the connection for the amplifier audio feed:
    [​IMG]
    Last edited: Jul 20, 2011
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  11. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 20, 2011]
    The saloons have a wee amp mounted on the nearside rear speaker, on all non-bose models afaik.
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  12. Oranoco
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    Oranoco Well-Known Member

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    [Jul 20, 2011]
    Do you have the adapter trims for the dash? If not I have a set I removed from my old Avant and then never used as the saloon already had an aftermarket radio in it. Happy to send them to you for gratis if you PM me.

    Don't bother with the adapter to run the rear speaker amp as it's expensive and sounds naff (I wasted money on one for the Avant). Simply run a fresh set of speaker wires direct from the headunit to the speakers.
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  13. B5QUAT
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    B5QUAT Member

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    [Jul 20, 2011]
    Does that mean that the Bose ones are straight plug and play (ie no need for the extra harnesses and the like)?
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  14. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 20, 2011]
    Nope, as there will be no connections for the BOSE amp. Plus if you put a speaker feed into a Line-In it would potentially blow the amp. (Spk= approx 10v/Line=approx 3v)

    Id think only the very early B5's would be PnP as they may not have an amp.
    Last edited: Jul 20, 2011
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  15. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 20, 2011]
    Yeh my old '96 had no amp and was plug and play.
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  16. LeeT
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    LeeT Member

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    [Jul 20, 2011]
    If blue thunder already has some i'd love them :)
    So my system is Bose what harness do i need?
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  17. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 20, 2011]
    Full Bose: PC9-408 if your new stereo has pre-outs, or PC9-410 if not.

    Half amped: PC9-401
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  18. Blue_Thunder
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    Blue_Thunder Active Member

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    [Jul 20, 2011]
    Thanks for all the input guys. Is there more than one type of PC9-401 adaptor? eBay seems to show pics of different ones, and i'm unsure why a lot of the listings are adament that they will only work in Car X or to replace Stereo Y.

    In the long run I may well run wires directly from the rear speakers to the HU, but at the moment all I want to do is buy one of these because it's cheap, cheerful and should roughly match the B5 interior, and I want to be able to hear music out of all 4 speakers next weekend when i'll hopefully be doing 500 miles in it... if I manage to get the car back on the road by then! As much as I love the sound of my Miltek, 500 miles of nothing but Motorway drone will not make me a happy boy.

    Reason i'm buying aftermarket is that i'm on my 2nd Concert after the 1st one packed in, this one has the volume issue in cold weather and terminally, the car has been sitting there with the battery unplugged for the last 6 months and I can't find the code!
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  19. LeeT
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    LeeT Member

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    [Jul 20, 2011]
    nice one mate. As you seem a bit of an expert on stereos, yes my stereo does have RCA preouts, but what does that mean exactly? What do i benefit by using the pre outs? As you can probably tell, i know nowt about stereo equipment
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  20. Oranoco
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    Oranoco Well-Known Member

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    [Jul 20, 2011]
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  21. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Jul 20, 2011]
    Concerts are ****e anyway, that pioneer looks like a bloody good buy.

    I was looking at its bigger brother myself (6300SD), but thats bloody tempting for 60quid!
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  22. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 20, 2011]
    Infotainment systems were my "specialty", if you will, a few years back. With regards to preouts, They are beasically "clean" outputs, they have not been adjusted or tweaked by the head units own amplifier, and as such you can get a broader control over the raw audio.
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  23. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 20, 2011]
    Finally got around to fitting the new stereo yesterday. Looks a lot less intrusive in the dash than a lot of aftermarket head units. I really think it looks good. Will get some pics up once i've refitted the centre console (but currently fannying about with some other wiring).

    Sounds pretty damn good as well for a £60 stereo, but... I didn't pick up on the above statement before about the rear speakers not working with a PC9-401.

    What do I need to do to get the rear speakers working, or is wiring them up directly to the head unit the only option?
    Do I need to reroute the wires from the now redundant red plug?
    [​IMG]

    Infact thinking about it, the blue and green plugs (which are stuck together along with the yellow one) aren't used either by the PC9-401 harness.
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  24. B5NUT
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    B5NUT Well-Known Member VCDS Map User

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    [Aug 20, 2011]
    One of the 2 wires on the red plug is the ground wire for the alarm, that will need to be connected to the back of the radio or the adapter plate.
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  25. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Aug 20, 2011]
    [​IMG] may be of help???
    #24
  26. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 20, 2011]
    Thanks Rconn. I'm still confused. The diagrams you've shown above suggest the rear speaker/amps are connected to the yellow part of the 3 coloured plugs stuck together. You can see from my pic above that there is wires from the adaptor going into those pins on the red plug. Does that mean I may have to move the wires from the yellow plug to some other pins?

    I suppose the best thing to do would be to 'trace back' where the speaker outputs are on the new HU and see which pins they go to on the PC9-401. Seems daft the PC9-401 isn't already wired up like that if that's the case.
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  27. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 20, 2011]
    Or do 'speaker outs' from the HU not work with Line outs on the Audi loom?
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  28. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Aug 20, 2011]
    How many wires go into the yellow connector? I suspect 4?
    #27
  29. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 22, 2011]
    Yes, 4 into the yellow connector:
    [​IMG]

    So that is the Line Out from the Audi Loom, and the wires do go to the back of the new HU, so i'm puzzled as to why this isn't working.

    Also noticed that all the radio presets get lost each time the radio is switched off. Does this mean the permanent live isn't correct on the harness as well, or could it just be a crappy 'quirk' of the stereo?
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  30. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Aug 22, 2011]
    Audis often have the ignition live and permanent wires switched round. Most head units provide a link wire to allow you to swap them over (usually red and yellow wires with bullet connectors)

    If you only have four wires then your head unit should be driving the front speakers directly, and the adaptor lead will be connected to the pre-out phonos on the head unit and an ignition live then to that yellow plug to provide the signal to the rears.

    I'll take a look at it for you if you fancy taking a run up the M6, or happen to be up this way anyway.
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  31. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 22, 2011]
    Might take you up on that offer Kev. Driving up to Edinburgh on Friday. Might take a detour Sunday on the return voyage.

    Checked the red and yellow wires with the bullet connectors. The red one was permanent live. Weird thing is, even when I switched the two around, the stereo still behaved exactly the same, ie: no power with no ignition, then turns on as soon as key is turned. Still no rear speakers either. Most confusing!

    Here's the head unit fitted:
    [​IMG]
    #30
  32. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Aug 23, 2011]
    Heh i'll be in edinburgh on friday too, probably coming back down here on saturday evening though. Your welcome to pop by on sunday, i'll PM you my mobile number and address details so you have them handy.
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  33. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Aug 23, 2011]
    Oh and most aftermarket head units will be "off" with no ignition, but the permenant live is used to keep the radio presets and other memorys active.

    If they're switched round, it will lose its presets every time you turn off the car.
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  34. acf8181
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    acf8181 Member

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    [Aug 24, 2011]
    #33
  35. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Aug 24, 2011]
    The rear speakers should already be connected to the pre-outs on your headunit using the PC9-401 mentioned above.
    #34
  36. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 25, 2011]
    Did some tidying up under the dash tonight when finishing the install of my water/meth kit (the eagle eyed among you might have noticed the switch on the fascia adaptor plates which doesn't belong there! :sly:

    Pulled the stereo out and had a better look. Aragorn, switched the red and yellow wires around it does now indeed store the radio stations. Much appreciated.

    Think i've also figured out why the rear speakers aren't working, but i'm buggered if I know how to solve it! As Rconn rightly pointed out, there should be four wires going to the yellow plug. RL, RR, COM and what looks to be a 'switch' on the diagram's he's provided. Well, dumbass me hadn't noticed that this final wire, for the 'switch' is not connected to the stereo. It's just a buller connection with no home to go to. Do I need to ground this, or send it to a live feed from the stereo? It's obviously an intentional design feature of the PC9-401, but what the hell am I supposed to do with it?
    :think:
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  37. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Aug 26, 2011]
    The ISO harness for the stereo often has a blue wire loose thats labelled "remote" or something similar.

    The bullet from the PC9 adaptor needs connected to there.
    #36
  38. acf8181
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    acf8181 Member

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    [Aug 26, 2011]
    Ah....its not. Have to confess it was a cheap ebay purchase and now i google a gen autoleads adapter i can see the difference. On mine it attaches the amp to the speaker outputs.

    So i guess i either buy a proper adapter or i just get a rca to speaker wire but use it the opposite way round (so preouts from HU are connected to amp input)?
    #37
  39. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Aug 26, 2011]
    Feeding speaker level signal would likely produce a distorted sound as the amp will be clipping.

    If you know what your doing, remove any level converters or filters from your cheap wire, and fit a pair of RCA's on the end and it should work just fine.

    Having just looked myself, PC9-401 is infact a pile of ****. You want PC9-404, which properly uses the pre-outs.
    #38
  40. Blue_Thunder
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    Blue_Thunder Active Member

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    [Aug 26, 2011]
    As I've been stationary on the M6 northbound for the last 2 hours, thought I'd take the opportunity to check this out. Once again the B5 Master was spot on. Thanks!!I wouldn't have thought to try that connection, as presumed the Remote wire would have been for a remote control.Now I can hear the traffic news from all 4 speakers... M6 still closed :-(Can you fix that too please Kev? ;)
    #39
  41. TrisLC
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    TrisLC Member

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    [Mar 24, 2013]
    Thread from the past..

    Is there anyway to tell which stereo I have in my car? I dont have BOSE stamped anywere, but I do have a small box on the underside of the rear shelf. So would this be an amp?

    If it is an amp do I need PC9-404 to make the rear speakers work.

    Ive just bought an new head unit and want to get the harness ordered so I can get it installed

    Thanks

    Tris
    #40

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