1. Time for some upgrades in server hardware and software to enhance security and take AK to the next level. Please contribute what you can to sales@audiokarma.org at PayPal.com - Thanks from the AK Team
    Dismiss Notice

Advice for servicing my recently acquired deck!

Discussion in 'Tape' started by Taketheflame, Oct 7, 2018.

  1. Taketheflame

    Taketheflame AK Subscriber Subscriber

    Messages:
    125
    Hey all,

    So, I've spent a bit more time with a tape deck I picked up a bit over a month ago (an Akai GXC-740D), and I've noticed a few (hopefully) minor issues that need some attention.

    #1 - The tape playback speed is slightly fast. Based on some stuff I've ripped into digital formats for fun using Audacity (and comparing them to a version on another format at the correct speed), it's playing about 2.4-2.5% faster or so than it should be. I've already looked into how to adjust the speed from finding a service manual/info online, and it sounds pretty easy to do - I'm just curious about what kind of screwdriver I should use. Is there a specific non-metallic/conductive type I can find, and should I be using electric safety gloves at all?

    Additional note - the tape speed is consistent throughout - no audible wow/flutter, or any other speed related playback issues whatsoever.

    #2 - There are some occasional channel/sound cutouts when playing a tape (it didn't do this the first couple of times I used the deck). Most of the time, everything is working fine, but I've noticed a couple of brief dropouts happen to either the left or right channel, but not both at the same time (the corresponding VU meter needle would drop during a cutout, so I don't think it's a headphone or RCA jack issue). I've had it happen with several different tapes, so I'm inclined to believe it's a deck issue.

    It seems most likely to do it from the beginning of playing a tape, and either goes away on it's own, or with an adjustment of the output knob - so I'm hoping it's just some stuff inside that needs a little cleaning/deoxit srpay. The question is - which parts should I be spraying first?

    Overall, the deck is otherwise in excellent shape/looks like it was well cared for, but it likely sat for several years too, so I expect that this is par for the course w/vintage gear. This is a nice deck I'm willing to go get serviced if need be (I know of a good, reasonably priced shop), but I'd rather DIY if it's easy stuff.

    Thanks in advance!
     

     

    Please register to disable this ad.

  2. oldvinyldude

    oldvinyldude AK Subscriber Subscriber

    Messages:
    1,648
    Location:
    Buckeystown Maryland
    On the adjustment item: You can use a small screwdriver, as long as it's not magnetized itself. It's just a pot, not an inductor. A plastic tool is safer, just in case you a fumbled fingered like myself, and risk bumping something metal in a damaging way.....

    Channel drop out-likely cleaning of a switch that switches from monitor to source. Get at that one with cleaner\Deoxit.

    Hope this helps
     
  3. Taketheflame

    Taketheflame AK Subscriber Subscriber

    Messages:
    125
    Update - there may be a bit more going on with this deck. I made a 1000hz sine wave tone file in Audacity, then sped it up by the estimated percentage that the deck's playback speed is off by. When I recorded the tone onto a blank tape, there was quite a bit of noticeable flutter on playback - enough so that I don't think it would be as useful for adjusting the deck speed as I had hoped for.

    Interesting enough, prerecorded tapes seem to sound fine on playback. I did stretch the blank tape out with a couple of FF and RW runs before attempting to record as well. The belts look like they're in good shape too...

    Any other ideas what may be causing it? I'm wondering if the tape itself could be a cause? (It was a sealed NOS TDK D60).
     
  4. Taketheflame

    Taketheflame AK Subscriber Subscriber

    Messages:
    125
    Update 2 - So, I'm wondering how to tell if it really needs new belts? Just how loose/tight should they feel? They feel similar/slightly less in tensity than the belt on my turntable. I threw in a quick picture here to see if anyone can spot any red flags (sorry it isn't quite the best). Also, how hard or soft are the pinch rollers supposed to feel?

    20181009_221718.jpg

    I did find a dirty looking connection terminal for the headphone jack and hit that w/cleaner, but this thing is mostly spotless inside. What's the best way to go about hitting the button switches w/spray? I read that you shouldn't get cleaner on the mechanical pieces for the transport, but the electrical connections seem well buried in there/close to the mechanical parts...
     
  5. VinceInMT

    VinceInMT New Member

    Messages:
    21
    While I am a bit of newbie when it comes to things like signal tracing I am unafraid to tear into a deck to get to what I need. I bought 4 decks in the past 6 months for the purpose of learning how to restore them.

    When it comes to switches some can be sprayed in place but for others there might be some disassembly required to get to them. On others I have had to remove the switch and carefully open it to get to the contacts. On a switch that is not designed to be opened, it might be possible to drill two small holes in the case, one for the spray and one to drain.
     
  6. oldvinyldude

    oldvinyldude AK Subscriber Subscriber

    Messages:
    1,648
    Location:
    Buckeystown Maryland
    On the belt-it's hard to say how loose they should be. I would be tempted to take a cloth with a modest amount pinch roller cleaner and carefully move belts through the cloth to clean them. It's tedious work, being careful not to stretch the belts in the process. Also, clean the metal surfaces where the belts run with isopropyl alcohol, but keep the iso away from the rubber.

    Pinch rollers should be pretty hard-but the surface needs to be 'grippy', not glazed\overly smooth.

    Even a spotless deck will likely have corrosion caused by being exposed to the atmosphere, over time. VinceInMT is dead on about switches and getting them clean. It can be quite a task if buried and no openings to get the cleaner to the contacts.

    One trick I use to keep the cleaner from getting where it's not desired-stuff an appropriate amount of paper towel around area to be sprayed. I also got some very long flexible straws to make things easier.

    Another trick, I sometimes tape the straw to my index finger and "point" to the spot I need. The other hand I can then use to hit the spray button on the can.
     
    Last edited: Oct 10, 2018

     

    Please register to disable this ad.

  7. MRL_Audio

    MRL_Audio AK Subscriber Subscriber

    Messages:
    5,858
    Location:
    St. Chuck, MO
    Why is that? Plenty of folks use that to clean rubber with.
     
  8. oldvinyldude

    oldvinyldude AK Subscriber Subscriber

    Messages:
    1,648
    Location:
    Buckeystown Maryland
    Some folks fear using iso to clean rubber. Did not want to get that debate going....
     
  9. BilboBaggins

    BilboBaggins AK Subscriber Subscriber

    Messages:
    3,492
    Location:
    Ottawa, Canada
    I would start by spraying deoxit into all the controls you can get at. The record adjustments, the output adjustment if present, and any other switch of knob with contacts. Great idea about taping the nozzle to your finger! :thumbsup: I’ll have to try that! Clean the playback and record heads and pinch rollers with alcohol. The belts should have good tension and spring back when stretched a little immediately. Expect to have to replace them, if not now, in the next few years. The other rubber parts are more challenging to get. Some can be rebuilt though. Keeping a cassette deck running requires a willingness to do some McGyvering.
     

Share This Page