04/09/2013 – Think back … way back. Nope, I can’t remember. Sometime in 1985 or perhaps 1986 I went to the Guitar Center in West Covina, CA (which was on the west side of Azusa at Covina Blvd, but has long-since moved to the old Standard Brands Paint building just across the street). Anyway, back then I spent a lot of time and money at the old store, often talking with a salesgirl named (stage name?) Coral Gables who always liked showing me the latest stuff – probably because I often bought the latest stuff.
One day she showed me this new Tascam 8-track recorder and I couldn’t believe it. All 8 tracks on 1/4 inch tape – all self contained with its own mixer. It was even setup to automatically switch the monitor when recording and playing back (i.e. no buttons to push between takes). So I bought one for $3000 plus tax, and brought it home.
I used it for many years, not professionally, but as a hobby and as a way to help me learn music composition and production. Then around 1993 I bought a PC and transitioned into midi composing, so the 388 was mostly used as nothing but a (good) mixer. Later, (around 1996 I believe) I bought a small Yamaha mixer for my desk and the bulky 388 was rolled out to our enclosed patio area, covered up until today. For fun (and possibly to sell it), I thought I would see if it still works, and also try to document what I found as I go along.
As I’m looking this thing over, I noticed the serial number is 100043 (below). Could this mean that I got one of the first of these boxes that was manufactured? Could be, I guess. And this thing was made in Japan. Nothing is made in Japan anymore.
Also, sometime perhaps in the early 90′s I could tell the main tape head was wearing out. I can’t remember if I judged this by looking at the head, or perhaps there was a degradation in the sound. Since the TEAC building in Montebello was within 20 miles of my house, I packed the thing up and brought it over to them to check out. Sure enough, it needed a new tape head, and if I remember correctly, it cost me less than $150 for the parts and labor. Such a deal …
So, as the original owner of this beast… let’s see if it still works …
Time to roll the thing out to the garage (on the rolling stand I made 27 years ago) and (gulp) plug it in. No sparks so far. Next I turned on the power switch in the back and … hey it lights up! All the meter lights are working and the tape counter LED’s indicate 0000. If I click some of the buttons red lights turn on and off. Now if I can just remember how to use it.
Making the Tape Move
I laced up an old 1/4 tape and pushed the Forward button – Hey it moves! But (uh oh) the center horizontal segments in the tape counter do not light up, making 8′s look like 0′s and other numbers unreadable. I pressed Stop and Reset and the machine responded properly. A little more Forward, then RTZ to return to zero and, hey … it all works. The tape counter is fed by the right-hand rubber guide wheel, which (amazingly) seems to still be in decent shape.
Play and Record
I fully expected all the rubber on this machine to have long since turned to dust, but oddly enough the thick pinch roller seems in very good shape. Maybe because I often used a rubber conditioner liquid way back when. When I pushed the Play button, the solenoid pushed the pinch roller into the capstan, and the tape appeared to move slightly, but then immediately stop. A few attempts resulted in the same problem. Oh well … something is broken somewhere.
Before I bother opening up this thing, let’s see if the mixer even works. I placed an SM57 mic (also purchased from Coral Gables) in front of a portable radio as a continuous sound source, plugged it into channel 1, pressed assign buttons to send it to tracks 1 and 2 (pan centered), adjusted the monitors, but no sound came out of the headphones. Ok … let’s jiggle some of the buttons and sliders. Knobs and sliders that haven’t been used in a while tend to gunk up and can be “cleaned” simply by working them a bit. Nope – no sound. Maybe the gain isn’t turned up enough? Louder … still nothing. All the way up – still nothing.
Then while poking at some of the assignment buttons for channel 1, I pretty much blew my ears out. Ahah … the assignment buttons need to be worked in. I lowered the gain and started pressing them. Sometimes I could get sound, and sometimes not. It became very frustrating until I found that if I pressed down fairly hard on the sheet metal of the mixer area, sound would go through. Bad connections somewhere I guess.
Some channels worked better than others. And some of the assignments worked better than others. After some work-in it seemed like most buttons were working, but almost all of the channel 1-2 assignments failed unless I pressed down on the buttons or applied some pressure to the metal mixer board itself. Something is wrong underneath.
Diagnosis (this section continously updated as I progress)
Problem Notes The VAR led doesn’t seem to light up. Maybe this requires the capstan to be turning? LED is definitely out. Need to remove transport board to fix, I think. Assigment buttons don’t all work correctly. Some work when held down, some when pressure is applied to mixer plate. Reseating the bus-bar board help immensely, but the red mixdown buttons still have issues. Possible we need more disassembly and a deoxidizer spray. Switches and knobs are dirty and need to be worked in. Knobs seem to all work well. Input assignment switches (Mic/Line/RMX) still have intermittent issues. May need deox if that might help. When the master volume is down all the way, sound all goes to left ear. Not sure what is happening here. Master pot broken. Will replace with new slider from eBay. Paint is coming off in some places – other minor dings here and there. Ignore it – On the Antiques Road Show this is called “patina”. Capstan drive belt has apparently reverted back into the oil from whence it came. Belt replaced with real TEAC product. Works fine. Tape counter LED’s do not display center segment. Intermittently, other segments do not light up. Reseated connectors under transport panel. Have not seen a re-occurrence of the problem. Capstan motor seems a bit noisier than I remember, almost a slight clicking sound coming from it. Problem was eliminated once belt was installed. The pretend leather is coming up a bit right near the Record button. Stretched and glued. Seems to be much better now.
On the Good Side
- When power was applied, nothing blew up or started smoking. Multiple power-ups and still no issues.
- All incandescent bulbs and all (almost all?) LED’s seem to be working.
- All meters are working.
- All 8 input channels seem to be working.
- Even without a capstan belt, I can use the tape lifter to show that (at least) tracks 1-2 can grab music off an old tape.
- Basic erasing, recording, and playback seems to work well on all 8 tracks.
- DBX noise reduction works well
- Variable speed control works (but LED does not light).
- Effects loop (may have to wait until I fix the SPX90 – or maybe I can use the effects in my Yamaha mixer)
- Archiving a dozen old tapes (possibly into a borrowed 8-track Pre-Sonus Audiobox)
- Remote control modification (notes are on back page of manual)
- Punch-in pedal (real TEAC pedal)
Opening the Top
I opened this thing up years ago to take a peek inside, and also to add my own port for a remote control. I remember the insides looked a bit like something from the 1970′s rather than 1985. But I’m not complaining, it could be that TEAC was just using their tried-and-true methods of electronic and physical design.
First I wanted to see why the capstan was not turning. I seemed to remember the front plate comes off of the tape area, so I removed the screws from the control button panel (as shown in the pictures below) and then removed the side bars and front panel from the tape drive area. Nope … nothing here but solenoids and the braking system.
Hmm… now that I see the braking mechanism, something in the back of my head remembers the brake pads being burned and brown colored. But there is no burning or browning now. I wonder if a brake failed or glassed-up and I had them repaired too. These look new so that could be the case. I do remember that after the TEAC servicing, I hardly used this machine. I probably intended to sell it and never did because there was no eBay at the time.
Time to pull the bottom off.
Opening the Bottom
Opening the bottom means I need to lift the entire machine off its stand and lean it up against something. Not for the meek – this thing is HEAVY. The bottom has a dozen or so screws that need to be removed and the entire sheet metal bottom comes off, revealing these complex innards:
Not shown in the photo above is the black goo which once was the capstan belt. It had apparently long-since fallen and stuck to the sheet metal bottom. So at least now we know why the Play button does nothing. Hmm … TEAC is still located at the old location in Montebello! Maybe I can call them and see if they have parts.
Fixing the Mixer Problems
Ok … why are there so many problems with the mixer? The pots and sliders seem to be working well and without any scratching (once I worked them in a bit). The top input switches (Mic/Line/RMX) were a little rough but also managed to be worked in with no problems. Since pressing on the top mixer plate seemed to help with the problems, that gives me the impression that we simply need to reseat some connections.
Sure enough, there’s a buss-bar board that crosses all 8 mixer boards (and then some, left above). I didn’t remove the board to reseat, but simply rocked each connection back and forth a few times and then pressed it firmly against each mixer board. I think that did it! Now I can input the mix on any of the 8 channels and properly route the signal to any of the 8 channels using the assignment buttons.
Fixing the Tape Counter Problem
Well, as long as I have the bottom open, let’s wander over to the pile of wires behind the transport control buttons, shown below, to jiggle and seat the various connectors.
Hey … that seems to have done the trick. The tape counter now displays all LED segments properly. Apparently old-age can be corrected by jiggling.
In the photo above, you may notice a blue connecter and ribbon cable at the upper left that is not part of the original 388. I seem to remember having great difficulty obtaining the remote control box for the 388 (whether price or availability), so I dug into the manuals and found the connection points myself, and routed them to the 15-pin blue connector. Here is the chart I made in the back of the manual:
I also made a small box with a few buttons and LED’s, attached to a 25-foot (or so) ribbon cable so I could control the 388 from my living room where the grand piano lives. I haven’t yet found that old box, but I’m sure it’s in the garage somewhere – I just need to dig. Or someone could make another using the chart above.
Ok, now I remember why I made this interface. The remote control that TASCAM sells doesn’t have all the buttons I needed on it.
Fixing the Capstan Drive Problem
This should be fairly simple. The web shows TEAC in Montebello has a phone number at 323-727-4840. I’ll give them a call tomorrow and see if they have a belt. There are also some belts available via eBay, but I’d rather get the real thing even if it costs more.
The capstan drive motor is always turning (even when not playing or recording), and it makes some unusual noise. Let’s take a closer look (below). You can see the motor pully and just to the left the larger flywheel which is directly connected to the capstan. And no belt of course.
The wheel comes off with a couple of set screws, and the u-shaped holding plate comes off with 4 phillips screws. The front of the motor looks like it could suck up a little oil, but the back bearing does not seem easily accessible. I put a small amount of tri-flow oil (the same stuff I use on my model helicopters) in the front, but there was no change to the slight clicking noise coming from the turning motor.
Then I happened to touch the spinning shaft with my finger and hey … the noise immediately stopped. With my finger applying even slight sideways pressure on the rotor bearings, the motor sounds exactly like it did when I last ran it almost 20 years ago. That means that once I get a new belt tugging on the motor, the noise should go away. Hmm… could be that is part of the design. Let’s get that belt tomorrow and see.
I thought of one more test I can do without the capstan belt. I put in an old tape which (I assumed) had music on it, and ran it back and forth 10 feet or so using the CUE and RTZ functions. While doing that I used the tape lifter to get the tape close (or touching the tape head. Music came out on tracks 1 and 2 (which I assume is all that is recorded) – so the tape head and electronics is probably in good shape!
During this process none of the mixer controls had any effect on the sound output except for the monitor knobs. I guess that’s how it works but I cannot remember. I rarely used the tape lifter in the past, if at all.
The TEAC building
Google says TEAC is located at 7733 Telegraph Rd Montebello, CA 90640 – same place I took the box for repairs over 20 years ago. Hmm… I don’t think the place has changed a bit! The big sign looks the same (or is it a different color? I can’t remember).
And the Google image on the right looks like the exact spot I parked in the early 1990′s when me and a guy from TEAC carried the 388 through that very door. I don’t remember the wheelchair ramp though. Guess I’m lucky to live in the Los Angeles area and have all this stuff nearby. Music production capital of the world (well, unless you count Nashville – but that’s Country).
TEAC – 323-727-4840
Replacing the Belt
04/10/2013 – Called TEAC this morning and talked to a nice guy named Gary. He says they do not have any parts for the 388 other than a few rubber parts. Cool… that’s what I need. So I drove over there and for less than $10 I have a new belt.
Replacing the belt is easy – there are two screws holding down the u-shaped bracket that keeps the flywheel in place. I actually only needed to remove one screw and loosen the other. Since the flywheel bearing sits on the bracket (gravity), I added a little grease there before putting it back together:
Once the belt was in place, the capstan strarted rotating smoothly and I could play back the old tape that was sitting in the machine for the last 20 years. One song was on tracks 1 and 2, which was the theme from the movie Littlefoot, recorded from a VHS tape. One of the last things I did was learn that tune well enough to make a midi recording cover for my wife’s cousin Thess, who liked the song at the time. No wow/flutter or any problems. Looks like the pinch roller is fine and the head works great (playing of tracks 1-2 tested so far).
The Master Volume Slider
I don’t know what’s with the master volume slider. It has no effect on attenuating the volume either during playback or monitoring. And when you move the slider all the way to zero the sound suddenly cuts off in my right ear, leaving the left ear working. Before I put the cover back on the bottom I will test this on the ohmmeter. Here’s a pic of the slider, and the designers were nice enough to hook it up with plugs for me to remove for testing:
Well, this dual 10K pot is shot, and in a strange way. Testing directly against the carbon surface shows normal resistance from the high side (left in the picture), all the way over until right before we get to the low end. Then there is a break and the ohms go to infinity. The odd thing is that both sides are broken in just about the same position. Don’t know what could cause that other than a manufacturing error. Wait a second … if that was the spot that the pot sat in for 20 years, and maybe when I moved it recently it stuck and broke the carbon. That actually makes sense. Luckily all the other sliders work just fine.
This explains why the slider had no effect on the sound output. With the low (grounded) end broken, the output from the sliders would have been virtually the same voltage regardless of pot position. And if the right channel break was in just a little different location from the left channel break, that would explain why the right side sound was lost when the slider was moved to its lowest level.
No way to fix this pot properly. Turns out there is a 388 pot on eBay (someone must be parting-out their 388) and I ordered it for 20 bucks. In the meantime, I will solder the connecters to an old 50K dual slider (I happen to have in my junk pile) for further testing. Update: The 50K temporary slider works fine, proving that only the old pot was bad and the circuits are in good shape.
Cleaning and Reassembly
I guess from years of use there are small bits of this and that in the tape drive area, plus finger dirt on buttons and frame. I cleaned all this up as well as possible before re-assembling the parts I had undone.
I can’t believe how cheap I was back then. Or maybe I put money into important things, and less into things I could make myself such as this stand made of 2×4′s. It also has some very heavy drawer slides (grabbed from a trash can at an industrial site by my dad) which slid out to hold my DX7 keyboard. Looks bad, but it worked great.
Originally, the stand consisted of only the parts painted brown. Later I added the keyboard sliders, and even later I added the unpainted plywood area to the right as a spot for cords and cables.