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Bender Comments Page

These are Reel to Reel Questions, Answers, and comments, things I've posted on several discussion groups, some when people write and ask me questions.


Comment #25

Subject: Question reguarding the Akai GX-635D reel to reel tape deck

Date: Mon, 01 Sep 2003 20:27:33 -0500

From: John Gado


I came across your web site while researching a problem I have with my Akai deck. I purchased this deck several days ago at a flee market, when I got it home I discovered that although the deck seems to work fine, the playback function (in any direction) has a problem. It seems that the speed control is not working correctly, when I press Play the deck will start playing but at an extremely fast speed.

My tapes are recorded at 7 1/2 IPS, however, the deck plays back the tapes at 3-4 times that speed (regardless of the setting of the speed select button).

I was wondering if you could suggest what I should look for, I'm quite proficient with a soldering iron and have limited diagnostic capabilities (in short - I know my way around), but I though I would ask before starting to poke around insides the deck.

I also wanted to say that your web site is quite impressive, you've collected a wide range of great information on these decks and it was a very interesting read. If you have any suggestions please let me know. Thank you.


********** And Bender Sez: **********

Hi John,

Most times I would suggest my Akai Servo Fix Kit, but in cases where the capstan motor speed is running at maximum, regardless of the speed switch, I found there is a much more extensive repair required. And that would be my SYSCON Rebuild Kit, which is a fairly extensive rebuild of the SYSCON Board, which isn't yet completed for the GX-635D, and also the manual isn't written. I've only seen this exact set of symptoms twice, so the need to complete the SYSCON Rebuild Kit has lagged...

One would most likely need the Syscon Rebuild Kit, and manual; the GX-635D Service Manual, and a Precision Test Tone Tape to complete this, so the cost will hover around $200.00 for those three items.

If you want to Pre-Order these items, the wait will be around 2 - 3 months more before delivery. The Pre-Order price will be $175. I suspect, as I'm working on a GX-255 which had those same symptoms, as well as my own GX-635D, and a GX-630D-ss at this time, with a GX-747 coming in tomorrow ( being driven in from Ohio.. ).

-Steven L. Bender

Comment #26

Subject: Akai GX365

Date: Wed, 10 Sep 2003 01:58:45 -0700 (PDT)

From: Michael

Hi Steve I was surfing your tape recorder site and I have a GX 365 tape recorder it wont play-i clicks/buzzes when you press the FWD button and if I put it reverse the capstan thing goes backwards then it stops and goes to the fwd direction again and of course wont go around.

It FF and REW no problems with very little sound and the motor goes the whole time. As it used record quite well and it "used" to play what could it be?

It is physically in quite good condition.

Regards Michael

********** And Bender Sez: **********

Hi Michael -

One thing you should understand... is that the possibility that a stored or unused set would fail to work when turned on. I just got in a mint GX-747dbx for repair, and also heard today from someone else whose GX-747 had not been used in 15 years and it now fails to play or work properly.

Most people have no idea that a set stored for more than 5 years may totally blow-up or fail once plugged in and turned on. Some sets will be damaged way beyond repair, as replacement parts have not been available for these sets for a long time; in the case of your early GX set - for over 30 years, or more.

Local repair people often don't know what to do with these sets now... In terms of keeping a set going, long term, and for repairs, finding a competent repair person for a treasured Reel to Reel machine can be an arduous task at best... Few among the independent repair places you will find in the yellow pages will still work on these sets.

Among the problems, and reasons, they typically cite are: 1) "Its obsolete equipment." 2) "We can't get parts." 3) "Can't get service data." 4) "Stuff is older than our technicians." 5) "Would likely cost more to repair than the equipment is worth."

To some extent, all of the above are true for most service places, which have to make a profit from every technician in the place, every month, to offset their rent and other costs. Since such service places are likely less than 20 years in the business, they deal with TV's, VCR's, and CD Players, and are likely unfamiliar with Reel to Reel sets, and are less inclinded to know about the proper functioning or of proper repairs for failures.

I have come across repair shops that take in a Reel to Reel Deck, and never finish it; one fellow said, after nearly three years his local repair place not only hadn't finished the repairs, they couldn't even find his Akai, when he demanded it back ( he was going to send it out to me ).

Most people don't know that sitting unused can cause parts in a set to go bad.

All of the upgrades and rebuilds that I specially designed for the Akai's - were specific to much later sets, those from 1974 or 75 and after, so my rebuilds will not work in your older set.

One thing I can say, that GX-365 used a lot of power relays, and I do not have replacement power relays for this set. They are not available from any source to my knowledge. Any replacements would have to be taken out of another GX-365D set.

While these Reel to Reel sets were still being made, some did fail, often in quantities large enough that Akai suggested in their 1970's Service Bulletins repairs for these known parts failures. I don't have any Service Bulletins old enough to cover the GX-365 set, so all I can say is that there is an inherent tendancy for power relays to arc which eventually ruin their contacts, and as such, the relays then need to be replaced or certain functions will no longer work.

Another relay related failure happens when relay contacts become welded together, this also causes a failure condition in which certain functions will no longer work. Next, the supporting transistor to diode logic of the operational block is also known to have failures in these early sets, so either the transistors, the diodes, or both - can also fail in there.

Any of these three things can cause the motor or some operational functions to fail - the same symptoms you report. Certainly the reliability of these sets over time will decrease, even when unused, as the relays are not hermetically sealed against air pollutants, which is the reason why many of the power relays were replaced with solid state logic and then proprietary IC logic in later production Akai sets.

The cost of repairing a GX-365 is likely in the $200. - $400. range, as it is rather difficult to judge what failures exist, since the resulting failure to operate symptoms can result from so many things, I've only gone through the three most likely of perhaps six different possible failure modes that leaves the set inoperative. Without having the set opened up and testing it in front of me, this is the total extent of troubleshooting that is possible.

I can supply you with the GX-365 Service Manual, it costs $25. also the GX-365 Parts List Manual is $25. either plus $4. Book Rate shipping; or $6. for Priority Mail shipping. These would be of help if you can find a local technician to track down these types of problems - if you can find one who is willing and capable of working at it.

Also these sets were pretty heavy, so shipping it bothways to me will run up to $100. So at this point it this set might not be worth repairing. That's entirely up to you.

If you do want to ship it out to me, I have detailed packing instructions which need to be followed to the letter to prevent in-shipping damage, which is rather prevalent these days for heavier packages.

Hope this all helps!

-Steven L. Bender

Comment #27

Subject: I am not sure what to do now

Date: Sat, 13 Sep 2003 02:11:14 -0500

From: Jason

Mr. Bender, I am a new user and unfamiliar with the nuances of analog tape. I was inherited an Akai -150D from a friend it is in good condition but it was in storage for some time. I would like to have a total work up of all electronic and mechanical functions, as close to a restoration possible. This might take a but of time and money and I am not sure who to trust. can you suggest a professional that can assist me in getting it right or someone who can help service it?

It was my friends wish for me to use it and I intend to record with it. Is this crazy, what say you? Jason Street

********** And Bender Sez: **********

Hi Jason -

Here is some basics: The X-150D was an older single motor Akai. These old sets - anything that old can have hidden problems. The older single motor Reel to Reel sets used cams, friction cams, wheelies, springs and rubber wheels internally and can have a multitude of mechanical operational problems thirty or forty years later.

The heads are NOT the GX crystal glass surface heads, and so your machines' heads are very subject to wear, and this will deteriorate any new recordings, and possibly the frequency response will be poor.

The metal rotating part is called the capstan, it is driven by a belt on the motor. The wheel part that contacts the capstan during play and regulates the speed is a rubber covered part called the: Pinch Roller. Together these regulate to speed that the tape passes over the heads.

In the case of the capstan older sets like the X-150D, which used a single speed motor, a larger metal capstan sleeve and a reverse thread knurled cap to keep it in place to operate at a faster speed. If this part is lost, it is nearly impossible to replace.

Some problems encountered would be - The problem of tape sliding off of the tape path which has several possible causes. First, the rubber pinch roller might be too slick and isn't gripping enough, or the set may have been left in "Play" mechanically when unused, resulting in a deformed pinch roller, or dents in the surface of the pinch roller, which needs to be properly "round" and "hard".

Also, the right side take-up reel torque could be too low, due to a poor or worn internal friction cam, this is also a common problem.

The capstan should have a smooth metal surface. Unfortunately, the capstan sleeves varied from Akai machine to machine, and is unavailable, also they are near impossible to duplicate.

The rubber Pinch Roller can be re-tired, a process which costs about $35. plus shipping is possibly more than an Akai X-150D is worth. Problem being is it is a combination of slick or deformed pinch roller and poor reel takeup torque, investing in the pinch roller may not actually solve the problem. :-(.

Another problem is that the inherent wow and flutter of this older Akai is about ten times ( at best ) that of Akai machines made some twenty years later; so you may find this wow or flutter to be objectionable in the recordings you make. Nothing can be done about that, except get a better machine; the W&F of a tape made on such a machine will always be present, even if the tape were to be played on a much better machine.

If the set has electrical problems, mechanical problems, or both, it could easily exceed $200. to get them repaired. Parts ,might not be available, and this will increase the cost ( heads are definately not available unless pulled out of a similar "low hours" set ). So while you can use it, or spend money to get it serviced, beware that is is always going to be limited by its age and its tolerances, likewise with its recordings.

To recap - Sets without the GX prefix were single motor, belt and wheelie driven, mechanically operated units with permalloy heads, which are very subject to wear. I'm not a big fan of any single motor set, but they are the most prevalent type out there, and the first ones to break down and stretch and irrepairably ruin tapes.

Those belt, cam, and wheelie based sets are infamous for having mechanical problems with the friction cams, wheelies and springs, putting dents in their pinch rollers and stretching tapes, among other things.

Repair costs on the early single motor sets are likely to be double what the set is worth, as will be the shipping costs if you have to ship it far to a suitable repair person. The only single motor sets worth fixing are the ones that had the GX heads, these were among the last Akai's made, and I did make one excellent working set out of two donated GX-4000D units with problems once a long time back.

In terms of normal 2 channel stereo sets, the best idea would be to get a better 3 motor set, so that if it breaks down it will be worth repairing. Among the more popular and quality vintage sets, depending on the numbers of heads and features you desire, those available at moderate prices, say from $100. to $400. these days... Akai's: GX-230D, GX-255, GX-266D, GX-267, GX-266II, GX-270D, GX-365D, GX-370D, GX-620, GX-625, GX-630D, GX-650D, and GX-77. Tandbergs 9000x, 9100x, 9200xd, Pioneers RT-707.

One could also look at a number of the Sony's like the TC-650 and TC-651, the Revox A-77 and B-77, and I'm sure others will suggest their fav machines, as the used market is so limitless... It doesn't pay to throw away money on a single motor set.

For those willing to spend even greater sums: the Akai GX-400D, GX-400D-ss, GX-636, GX-646, GX-747, GX-747DBX, and PRO-1000, Tandbergs 10XD, TD-20A, and TD-20SE if you can find a working unit, Pioneers RT-909, Sony's TC-766, and similar sets will often set you back about $500. to $700. or more... depending on condition, level of repairs, accessories, and upgrades.

-Steven L. Bender

Comment #28

Subject: Re: TDK GX 35 90B tape

Date: Tue, 21 Oct 2003 00:33:35 -0700 (PDT)

Jim Barrentine wrote:

Does anyone besides me have any problems with this tape being so dirty. I play one 7" reel and my Teac X-10R is so dirty I spend 10 to 15 minutes cleaning. This tape is supposed to have a life time warranty but I don't know who to contact.

Thanks for any help

Jim B.

********** And Bender Sez: **********

Hi Jim -

I have to admit my own TDK GX seems to shed a small amount of white dust, and most of my reels are the slightly older TDK Audua, Audua/B, or the LX / LX-B so I don't have much GX to use as a reference, but what you have sounds like classic Sticky-Shed Syndrome, whose symptoms onclude: screeching sounds when the tape passes over the heads and tape guides; and brown or black gunky residue left all along the tape path.

Many later production reel tapes were affected in such a way that batches from late 1970's to the mid 1980's, so at some point, almost all brands of reel tape were affected with problematic batches.

After whale oil was outlawed, a synthetic substitute had to be used, so the binder which retains the oxide onto the plastic backing is made of different hydrocarbons. When the content or ratio of long to small polymer hydrocarbon chains was apparently improper, tapes slowly became hydroscopic - began absorbing water from the air, with the end result - Goo and Sticky-Shed Syndrome.

Tape is subject to a bunch of ills, high temperature and humidity can be the worst offenders, and while fungus spots can be the toughest sickness of all, caused by mildew and mold which can be smelly and physically seen and even this apparently has a cure.

After 5, 10, 15, 20, years... these affected tapes shed massive amounts of oxide. Tapes affected include mostly Ampex 406, 456, Sony ULT, SLH, Scotch 808, 807, 806, 226, 227, some 206, 207, and maybe a few others.

Some backcoated tapes also seem to have a similar but possibly unrelated problem, where the backcoating would drift and ooze to the tape edges making adjacent tape layers stick together, forming clumps of the black backcoating material, a condition usually worse in tapes fast wound and then left for years. That I've only seen this in some Sony SLH and ULH tapes, and a couple of later Barkey-Crocker pre-recorded reels.

Such tapes can be baked in very low temperature ovens to be playable for a few weeks, but eventually the audio must be transferred onto another tape ( which requires a second tape deck equal or better than the original ) as the sticky-shed returns and tape becomes more ruined with each loss of oxide shed.

BTW - If you do return your tape to TDK under the lifetime warrantee, TDK will return your tape to you, as they no longer make reel tapes, and have zero stocks of the stuff. In my case they also sent a box of audio Cassettes, which they offer as a sample of the current products :-(.

Hope that helps,

-Steven L. Bender

Comment #29

Subject: Re: Saving Sony Sticky-Shed Tapes!

Date: Tue, 18 Nov 2003 08:39:58 -0800


Have you figured out the mystery of TDK LX and GX tapes? or tried to save those? I always thought that TDK tapes were comparable to Maxell in terms of sound and longevity. Years ago, I bought several reels of TDK Audua L (no "B")and TDK LX35-90 (no "B") tape from Circuit City and they still sound and look great with no oxide loss whatsoever (always stored in my stereo cabinet).

Well in the last month on Ebay, I bought 4 reels of GX35-90B tape and 2 metal reels of LX35-180B from different sellers. All 6 reels are catastrophically spitting out white oxide flakes everywhere and with the 2 Metal reels this oxide shed has caused pitting on the inside of each reel (some sort of chemical reaction?--what in the world!!).

I tried baking some of the tapes like I do my Ampex, but that didn't even work. Can this TDK tape be saved? Should I stay away from the TDK "B" types? You know its amazing, I've never noticed one bad reel of Maxell tape (LN, UD, XLI, XLII), Scotch (Classic, 178, 996, or 207) or Realistic Supertape (both the blue and silver box types)--what did they do differently?

I hate tapes with dandruff!! I sure do miss Maxell-manufactured tapes! and new Radio Shack tapes sound HORRIBLE (no bass response)!

********** And Bender Sez: **********


I have about 50 or 60 Audua reels ( older silver box ) from the '70's and no problems so far. Knock on wood !~! I also have maybe ten still sealed Audua reels and I hope no problems show up.

The TDK LX and GX, I have about 15 reels mostly backcoated version, some plain, and didn't notice any problems ( but then I haven't been looking for them :-). Still I notice an occassional few white specks. Someone else has also complained to me about seeing white specks after playing TDK LX and GX tapes.

White stuff would not be oxide. I don't know if it is fungus, excess binder flakes, or maybe dried lubricant ( most likely I think ) or what....

Turns out there are SO many ills that can affect tape... I really don't have any good answers when it comes to TDK and Scotch Reels. One GX reel seemed slit poorly, but ya know its way difficult to find out if that was a factory problem, or something that happened due to a poorly maintained reel machine ( Akai 4000 and other single motor machines with springs, wheelies, and friction cams can stretch and ruin tape if mal-adjusted! ).

I have had bad Scotch 808 reels both 7" and 10.5" reels show up here, and I think one 207 which wasn't good, but sometimes its difficult to know what tape is actually on a reel and is it the reel that goes with that box... 30 years later... I'll agree that Reels of Scotch Classic so far seem fine.

Of all the explanations or not-explanations I've heard, it seems that the ratio of long to short hydrocarbons in the binder when synthetic stuff was used in later production tapes was at fault. Seems when measured ( as far as I can read between the lines ) these things "average" out, so it looks right even if the ratio is way, way off.

So when they mixed up the soup ( oxide, binder, and chemicals ) it seemed OK, but after the tape production was finished, 5 or so years later the problems started showing up, much to the perplexed chemists.

Apparently, the techie's and chemists much to their lament soon discovered that their measuring equipment simply wasn't sensitive enough to catch errors of this sort and they probably had to invest in some rather costly new technologies to determine the actual specific ratio's of long and short chained hydrocarbons in their "soup".

I also notice that how well the oxide sticks to the plastic backing under stress or under normal playing conditions also differs among different good tapes... some tapes the stuff starts falling off if you just look at it mean... 1970's Basf LP-35 dry sheds a bit off every pass on the reel. If one stretches a length of TDK, Scotch, Sony, whatever, usually the oxide stuff is already falling on the ground before the tape is "wire thin".

But recently I tested a Basf/Emtec LPR-35 and it has almost no oxide shed even if the tape is yanked and stretched to "wire thin". This is pretty much current production, as a small print four digit number on the box, which I suspect is a date code, puts it as a late 1998 product.

Hate to say it, but tape's still a mystery to me... :-).

-Steven L. Bender

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Last Update - February 5th, 2004 9:00 PAM.

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