AKAI GX-77 R2R New to Me - replace fuse and go!

Discussion in 'Tape' started by IanMcI, Feb 4, 2017.

  1. IanMcI

    IanMcI Active Member

    Messages:
    285
    Location:
    San Mateo, CA
    I just picked up this AKAI GX-77 at an estate sale. This was very last minute, and this was literally the last item of any worth left. The seller noticed it was plugged in and turned on (pointing to a light), but merely unplugged it and said "It's yours - free". Of course, I grabbed it and ran!

    Got it home, plugged it in, the digital readout came on, and the control light came on, then, after about three seconds, nothing. No power.

    I removed the back, see four fuses, with one of them blown. Well... cool, I guess. So tomorrow, I'll get the appropriate fuse and give it a go. Is this pretty much what one would do in a situation like this? I don't have testing equipment, but I've soldered and recapped and fiddled and whatnot before, so I'm not an idiot, and I know to be very careful around electronics. I'm just hoping that there may be reasons for a fuse to blow once, then have the piece work fine after replacing it. I've done that before, no problems. But I guess I never asked this question before. Is that typically how one would/should proceed?

    It's a very clean (near mint) machine; owned, I assume, by an older audio enthusiast (given the the style of furniture and such that appeared in the CL ad). No scratches or dirt. No signs of abuse. Very clean in and out.

    Can I expect a good chance that with the blown fuse replaced the machine may just be good to go?

    Ian
    SF Bay Area
     
  2. MRL_Audio

    MRL_Audio AK Subscriber Subscriber

    Messages:
    6,321
    Location:
    St. Chuck, MO
    Hard to say but my guess is that the fuse will blow again. There's a reason it blew. Unless you understand that it's a 50/50 crap shoot on it happening again. There is a service manual on HiFi Engine. Need to be a member to download but it's free and worthwhile to join. Have 2 77's. Love em when they work.
     
  3. IanMcI

    IanMcI Active Member

    Messages:
    285
    Location:
    San Mateo, CA
    Thanks for the input!

    I should first point out that I meant to end the title of my thread with a question mark, not an exclamation point, but couldn't see a way to edit that.

    I'm thinking, as it will be easiest for, to simply replace the fuse and hope for the best. I've had other pieces over the years, especially those that were new to me and perhaps had sat for quite awhile, come back to life with a blown-fuse replacement.

    If the new fuse blows, then I'll have more to worry about, and may then begin looking further into the guts of this thing.

    Ian
    SF Bay Area
     
  4. RenD

    RenD Active Member

    Messages:
    111
    Location:
    Québec
    Fuse can blow of old age. If it's the case here, good for you :) if not, get it fixed.
     
  5. RenD

    RenD Active Member

    Messages:
    111
    Location:
    Québec
    Also, pics please :D
     
  6. IanMcI

    IanMcI Active Member

    Messages:
    285
    Location:
    San Mateo, CA
    Fuses tomorrow at a local electronics store. Tried Radio Shack today - they didn't have the 125v 1.25A that I needed.

    Pics, indeed:

    akai-1.jpg akai-2.jpg

    Ian
    SF Bay Area
     
  7. RenD

    RenD Active Member

    Messages:
    111
    Location:
    Québec
    A truly beautiful piece of machinery indeed :bowdown:
     
  8. IanMcI

    IanMcI Active Member

    Messages:
    285
    Location:
    San Mateo, CA
    Well, I replaced the fuse, and it powers on, as far as the tape counter and illuminated Stand By arrows indicate. But, other than a mechanical clicking noise, I'm getting no response to controls.

    I believe the mechanics are stiff from this machine's having sat for some time. No indication of dried lubricant (yet).

    Question: should the pinch rollers be fairly movable? I figure they must move to some extent in order to actually pinch. I ask, because the service manual suggests a dismantling procedure that includes removing screws that are behind the pinch rollers. The rollers are currently in an up position, though not so much to actually be able to pinch tape. Looks like they need to be in a retracted position for me to get to the screws behind them.

    There is a Cue/Review button whose mechanics I can see and partially access. It was stuck in the "on" position. I'm able to move that mechanism to its "off" position with the help of a screwdriver. Experience suggests it's sticky with disuse. This suggests that other parts are probably unwilling to operate as they should. I can see where if I can get the pinch rollers to retract (manually), I can access most mechanical action for treatment (hairdryer/lubricant, etc.).

    I'll check to see if there is a better place to talk maintenance of this order, but would appreciate any help with learning how I might get those pinch rollers to retract without, at this time, powering up. Thanks!

    Ian
    SF Bay Area
     
  9. phantomrebel

    phantomrebel Serial Tapist Subscriber

    The number 1 issue with this deck is rollers stuck in up or down position due to grease hardening. The entire mechanism needs to be disassembled, cleaned, and re-lubed. This involves a lot of work and there many threads around on how to do it if you do a search. Simple treatment from the front is not adequate. The number 2 issue is the spring holder on the loading roller often breaks, but there's a fix with adding a simple screw. While you have the deck open, replace the belts. It's a PITA. My deck GX-77 still does not run properly and I am convinced they are over-designed, weak pieces of gear.
     
    Last edited: Feb 8, 2017
  10. IanMcI

    IanMcI Active Member

    Messages:
    285
    Location:
    San Mateo, CA
    The grease in this machine seems to be good. I have experience with vintage sewing machines wherein the old grease has hardened to the consistency of cement. This exhibits none of that. Still, I used a bit of Tri-flow at all pivots to ensure ease of operation, and I think things are pretty good in that regard, except for the right-side tensioner, which still has a "gummy" fill.

    I have dismantled the chassis to a considerable degree, as can be seen in the thread I have going in the DIY section: http://audiokarma.org/forums/index....rollers-on-akai-r2r-looking-to-repair.755806/

    As noted there, I did get the pinch roller to descend. I required that I "trip" a lever, then rotate the white plastic drive gear. This drove the rollers down and allowed for further dismantling of the front fascia.

    I should also note a tag, or label, on the back of the machine that mentions a local AV repair company with a warrenty number. It may be that this was in for service or repair at some point. Maybe that's why the grease is good. I will say, there is quite a bit of grease in springs - like INSIDE the springs, where it can't possible be doing any good (and could possible be doing harm, though it doesn't appear to be). I wonder what that's all about.

    Ian
    SF Bay Area
     
  11. phantomrebel

    phantomrebel Serial Tapist Subscriber

    I just saw that other thread. The found spring may be the loading roller that I mentioned...it's tab may be broken (very common)...Its in the middle of the first pic (yellow arrow). I didn't see this spring in your pic, but it was dark. Then there is a plunger arm spring inside that could lead to problems with loading as well (second pic). The pivot on this plunger can get stuck with old grease as well so clean it (red arrow).
    akai-gx-77-front-verwijderd-1024x576.jpg
    akai-gx-77-plunger-arm-met-pijl.jpg
     
    Last edited: Feb 8, 2017

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