What you need to know for Repairs

Over the last 45 years of service in the Electronics Industry, I have worked on anything from Coffee Pots, Rice cookers, VCR’s, Camcorders, Digital Betacam, and then Transmitters in the AM and FM Radio business.  There is a lot to see. But in working on consumer tape decks and amplifiers there are a few things that stick out for anyone wishing to repair electronics should watch out for.

They can be things like poor wave soldering of the boards. There is so little solder on these parts that the smallest bump or vibration will cause a failure of that circuit. Multiply this by 100- 200 joints in a machine and you have a real good chance that it will need repair sooner rather than later. Other things that can break weak joints are conditions of thermal cycling. Does the part have a heat sink on it or does it get hot? Well so does the joint. So many cycles will make the solder joint weak and it was develop a ring around the part lead and again an intermittent connection or break. Corrections done by a good Technician who knows how to solder using Kester 44 (Lead) solder will do wonders for the longevity of the unit.

That is not the only thing that causes failure. There is the infamous 10 V Electrolytic capacitor. These 10 V types have proven a very high failure part so that I often tell others that I am allergic to 10 V caps. Many a tape deck or other equipment that have this part are on borrowed time from when they are made. I just was working on a Teac Z6000 tape deck. Playback was lost on the left channel. Further examination indicated that the coupling cap was defective and must have had a bad connection inside. What value was it? 220uFd/ 10V. Not the type of part I would expect in a $1500 tape deck. Don’t feel bad Teac, Revox and Uher have their Frako caps too. They are notorious for shorting.


OK, Now for the X series tape decks from Teac. Some think that having dual capstan drive is a plus. Technicians can tell you what a headache they can be. There is sensitivity to belt length, belt position, how clean the pinch rollers are and dirt on the capstan shaft. However, what causes me to write this is that I have also found the the two conditions that are seen are either Skew or tape looping. Looping is when the tape comes away from the heads making a perfect loop down below them. This is most likely caused by a loose belt. Most all X series need a 16.8″ belt but some sell 17″ belts that are near the limit to not use them. They sometimes do not work and if they do only for 6 month. Marrs has the good belts at 16.8″ X .330″ wide.

Next there is Skew. This is when the tape travels off the straight path at the pinch roller. I have determined recently that some genius adjusted the head position on the head block so that they are tilted and THIS make the tape skew. Of course the machine never works like they adjust them. Just go turning all the head screw and you are sure to make the deck better- Yes after about $160 of Technicians work. Rule is don’t touch these screws you need a lot to put them back into position.. Please,I have more than enough work already.

The best Service Manuals come from Stereomanuals.com .  If I do not have one I need that is where I get them!

In Canada, A new site for service in your area may be this one here. http://reeltoreeltech.com/

Give them a call and see if they can help you. Tel: 604-514-1751  Talk to Curt.     Email: info@reeltoreeltech.com

11 thoughts on “What you need to know for Repairs”

  1. Sam,
    I have several reel-to-reel tape decks that need repair due to water damage. I was wondering what the estimated cost to repair.
    Allied (Model #TR-1035)
    Stereophonic Recorder (Model # 722)
    Panasonic (Model # RS-7615)
    LaFayette (Model # RK-132)
    Sony (Model # TC-440)


    1. Hi James,
      Units that are subject to any major portion of water and not sprayed clean and then dried right away with the aid of alcohol and fans are usually not recoverable as the repair of them would far exceed the value of the machine. For example, a guy brought me a Teac X-3 with some discoloration in the one meter. I said what happened- he said it was in water. I opening it up and it was in up to 90 percent of they unit. After parting it out for some mechanical parts, the PCB was clearly a lost cause and if you bought all the parts your would need to restore them provided they could be obtained, the cost might be $3000. You could have bought a restored one for less than that.
      Most all of these models are older units that also bring their own additional problems. I really do not accept water damage units as if even costs me money to work on them.

    2. The amount of water damage must be assessed by inspection. I had one X-3 come in that was under 11 inches of water. The meters had started to rust or give that color. The only way to see what the deal was is to open it up. After inspection the PCB on the bottom was all full of rusted parts- pots, resistors, Meter need replacement- it was estimated to be beyond repair and over $3500 to even attempt it which I do not have time for. It is then better to never subject the units to water as some deck parts can not have water in them at all. They will fail due to rust. The hours to take all that apart and repair it could take a $300 tape deck into $20,000 cost when you actually rebuild it from spare parts. There is no easy way to fix these.

  2. Hi, Sam. I discovered you on Tape Heads while looking for a solution to my DX-4D issue, and found your responses to be most knowledgeable. So I’m hoping you can give me some direction.

    I recently purchased a TASCAM DX-4D to interface w/ my TEAC A-3440, and the problem I’m having is that the DX-4D works for only a few seconds after it’s turned on; but, then soon after, the LEDs turn off, and it stops passing audio. Have you ever faced this issue, and if so, is it a simple fix? What can I do to resolve? Thanks in advance!

    Best regards!

    1. Hi Keith,
      The A3440 deck does not have the FV signal to put into the DX-4D to enable it even though the connector type is the same.
      The DX-4D is looking for a TTL level 1 Hz square wave which can easily be built using a NE555 timer chip but even though I did that back in the 80’s I found a better way to defeat this silly system. I open the DX-4D up, find the FV signal board and then take the wires that are the output and solder them together and slip heat shrink over the solder joint. Then after that the cable and all that circuit can be removed as it no longer is needed.
      To get detailed info I need to send you some drawing or schematics by E mail.
      Contact me at skywavebe@sbcglobal.net

      1. Thanks, Sam. Found your mod, and it worked. I’m of a mind to have my unit thoroughly serviced, and will email you.

        Best regards,


        1. Hi Keith,
          Any Technician of the least possible grade would be able to figure this out as it is not all that hard to do.
          I did it back in the 80’s. If the unit works for you and sound good then no need to service the dBx unit. Most often the reason people think a dBx unit is not working correctly or that it has adverse effects is due to their tape decks being so far off the calibration. This is what needs service not the DX-4D as these are very stable and break down rarely. In fact in my 45 years in service I had to only repair one DX unit and it was a power supply problem. They just do not break.

  3. Sam, can you help me out with some wiring information. I recently moved and can’t remember how to wire connect my Teac A3440 to my dbx150. It was working very well for years, but, I forgot how to wire them together.
    Can you help?

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