I have been going through my Akai GX-635D and cleaning it out and tuning it up as much as possible. I am in the process of trying to find a service manual for it but was wondering if any Akai Experts out there could tell me what these adjustments are for on the bottom PCB ? (See arrows on attached picture) The previous owner striped just about all the screw heads for the head adjustments. I have replaced all 12 screws (3mm). I do not have a head alignment test tape, so to improvise, I am using a 7 1/2 ips RCA Pre-Recorded Chet Atkins tape (which sounds great by the way) to adjust the play back heads. I will then feed it a signal from a CD player and try to align the record heads on some Maxell UD-XL-1 Tape that I have. I doubt it will be perfect, but I think I can get it in the ball park. All things mechanical have been cleaned, greased where needed and DeOxIt in all the controls.

I don't have a 635 to know beyond this....the two larger items you have arrows pointing to are the trimmer capacitors that adjust the bias level for each channel.
The record section will have trimmer pots for record level (and possibly VU meter calibrations too). The reproduce section will have trimmer pots for repro levels and repro EQ as well.

With a pre-recorded tape you can perhaps get everything semi-tweaked to where you can see if there's justification in ordering a proper alignment tape. JRF Magnetics is a good place to order one when the time comes.

I just hope the thing hasn't been run to death in the past with the heads severely misaligned. About 12 years ago I straightened out a Teac A 3340 S whose record head height had been tampered with such that half of the gap of track 4 jutted out below the bottom edge of the tape! The machine could not be calibrated due to this head having been destroyed from years of hard use with this gross misalignment. The machine had to have both the record and repro heads replaced. At least I was able to get the proper heads for it. Best of luck with your 635!!

I scanned my service manual awhile back and made a mini-manual of all the important stuff. I'll upload it when I get home.

One thing to watch for, a common problem, is in reverse play, you get the forward tracks played backward. In your picture, the long bar above the green arrows, is supposed to move back and forth (or left and right) - controlled by the solenoid on the right end of the bar. While you have it apart use some contact cleaner on the switches that are shifted by that bar. This will head off a likely "inevitable" problem.

tapehead

Thanks tapehead,

I cleaned the switches that bar controls and put a little grease at the far end of the bar where it slides. One question, is it good to clean the solenoid with Deoxit or just contact cleaner that has no lube in it.

Ozric-
I used contact cleaner on mine. I don't really have an opinion about anything with lube in it - I've never used it. Others may have another opinion. I'm mainly a Teac guy, with a few nice Akais. Good luck!

tapehead

Never use lubricant on solenoids, it will gum up. Just clean with IPA. I am uploading the SM right now to Yousendit. I'll PM you with a link and post it here also in case anyone else wants it.

Service manual can be downloaded at:
http://s50.yousendit.com/d.aspx?id=3NOCMFBF8JB7A3DSYGWWSHXW1L
37 Meg file!

Warren-
Thanks for the SM for GX-635D!

tapehead

You're welcome!

Thanks again dr*audio for the 635D Manual. It has made things a lot easier to figure out as far as getting everything adjusted on this machine.

hi all....
I tried the above given link to the GX625d manual..i got a page not found message....hmm..
also, i did finally find a downloaded service manual for the GX635d...and i printed out the pages that show the id for the bottom pc board with the adjustments for the playback and record levels..forward and reverse, .they are id'd....also printed out the page with the adjustment levels....using a test tone tape etc....BUT Unlike in the Teac manual for the 4300 and 6300, the procedure and sequence of events to make proper adjustments is NOT provided.....
can it be the same as Teacs????
thanks..for a great site blooeyz