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TEAC 1230 clicking issue

Discussion in 'Tape' started by Drew Bennett, Nov 10, 2018.

  1. Drew Bennett

    Drew Bennett New Member

    Messages:
    3
    Hello!

    This is my first post here... I'm just wondering if anyone would know how to fix an issue i'm having. I picked up a TEAC 1230 for $25 off craigslist. I fixed the sticky pinch roller and deoxited everything, and it sounds great. Yet recently, it's been giving a slight, high-pitched crackle/popping sound out of the left channel. It sounds similar to a dirty record. The issue gets worse as you play it.

    Here's what I know:
    - It's only the left channel.
    - No other concerning noises.
    - Headphone output compromised as well.
    - Issue is NOT present while listening to the external inputs going through the machine.

    Is this worth re-capping? And if so, does anyone know what capacitor it would be? I don't have any idea.

    Thank you!
    Drew
     

     

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  2. rojoknox

    rojoknox Active Member

    Messages:
    100
    Location:
    Gresham OR
    Greetings from RojoLand!

    A Teac 1230 is nearing 50 years old. ALL the electrolytic capacitors should be replaced. Green Mylar caps should be fine. And if you encounter any gray Suzuki "oil capacitors," they should be replaced on sight. They are little time-bombs waiting to go Pop-BANG! I speak from personal experience. Use 0.1 µF 630 V yellow axial film caps to replace them; cheap and effective.

    The 1230 uses a wafer switch for play, pause and fast-mode. That wafer switch is becoming known for failure and will be difficult to replace. Check it out carefully.

    HiFi Engine has the owner's manual online. Unfortunately, they don't have a service manual. You'll have to hunt that one up (and may have to pay $$ for it rather than a free download).

    Does the crackle/popping sound go in and out, or do anything other than change level, when you rotate the Output control back and forth? Those pots may need more DeoxIT if so. (Use DeoxIT F5 for the pots.)

    Take care,

    J. E. Knox "The Victor Freak"
     
  3. Numone

    Numone Active Member

    Messages:
    116
    Hi and welcome to AK.
    I have a A-1230 2T which was used in many European radio stations. It's a nice deck.
    How are the heads? Can you upload some good quality close-ups?
    The Pause/Play/Fast switch issue Rojoknox mentions is repairable, by moving the wiring from the damaged wafers to the unused, and thereby, undamaged wafers which are avaible on the switch. I know this as I had the switch fail on our A-3300-10 and the fab tech I use had it fixed in less than a couple of hours.
    What you must do is to really lubricate the motors through the oil tubes - use a oil syringe to ensure you get plenty of oil in there; work on the basis they may never have been lubed! Once that's done, put the deck on its back to allow the oil to go down the shaft to the rear bearing. Also, change the capstan belt. There is a service manual available for the physically identical A-1250 on HiFi Engine - https://www.hifiengine.com/manual_library/teac/a-1250.shtml. You'll need to join the site - its free - to download it.
     
    rojoknox likes this.
  4. Drew Bennett

    Drew Bennett New Member

    Messages:
    3
    Thanks so much for the reply! The popping does not go in and out. In fact, it’s very consistent and rapid. It does get louder with the output knob, along with the music. If I were to replace them, how should I identify the electrolytic capacitors? How many would you say there are? I’m away from home now so I’m not able to post a picture of the heads, but they’re in good shape.

    Since this thing is so old, do you think it’s worth it to service?

    Thanks again!

    Drew
     
  5. Numone

    Numone Active Member

    Messages:
    116
    Yes it is, Drew, because all these 50 year-old TEAC decks are becoming rarer and rarer, because people still chuck them away/brake them up for spares, so if you can afford to get it to a good tech to properly diagnose, fix and then service it, it'd be great to do so - with light use you'll then enjoy it for another 50!
     
  6. rojoknox

    rojoknox Active Member

    Messages:
    100
    Location:
    Gresham OR
    Greetings from RojoLand!

    I second Numone's statement.

    Electrolytic capacitors are generally tubular, in an aluminum case, and are polarized (marked with a positive and/or negative terminal). They have specified capacitance and working-voltage ratings printed on them (as do many other capacitors). The problem with electrolytics is that after all these years they are prone to drying out internally, or becoming "leaky" (meaning they begin to exhibit a resistance which can upset circuit operation or lead to failure of other components). You'll need to acquire the service manual to find out how many are used in your set.

    Take care,

    J. E. Knox "The Victor Freak"
     

     

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  7. audiojones

    audiojones Jonesin' for audio Subscriber

    Messages:
    7,170
    Location:
    Central NJ
    Hi -

    From your good troubleshooting it sounds to me like your problem is a noisy transistor in the left channel of the playback amp board (also called the head amp board). Since the noise is present when playing a tape but not when listening to the source through the deck that rules out the line amp and points directly to the head amp. Since it affects only the left channel that narrows it down further, and since the symptoms you are describing are very typical for a noisy failing transistor (a very common failure at this point) your most likely suspects are either Q101, Q102 or Q103 head amp transistors.

    The schematic for your exact model doesn't seem to be available from the usual sources but your amplifier board should be the same as the one used in the 1250 (the auto-reverse version of your deck). Of course you should check your machines head amp board before assuming they are the same but the layout should look like the screenshot below (disregard the forward / reverse head switching relay, yours won't have that).

    The head amp circuit uses three transistors per channel to bring the playback head signal up to the proper level for the line amp input (which is routed through the Source / Tape switch). For the left channel they are Q101, Q102 and Q103.
    image.png
    Q101 (2sc732) and Q103 (2sc828) can be replaced with commonly available KSC1845.
    Q102 (2sa494) can be replaced with KSA992. These are modern subs that should be ok in these positions, probably best to replace the same three in the other channel (Q104, Q105, Q106) to keep things even.

    (Please note that there is another schematic in this manual with a typo that mixes up the NPN / PNP symbols for Q101 and 102, don't be confused by it!)

    Not saying this is absolutely your problem but the symptoms certainly point that way and it's a fairly common problem I've run into in the past (less frequently with TEAC but I've seen it happen). If you've never replaced transistors before there are plenty of good tutorials here and on YouTube for identifying the legs and getting them installed correctly. Don't bother trying to test them, noisy transistors almost always test ok with simple basic testing (you need sophisticated test equipment to test them under load conditions) so it's best to just go ahead and change the suspects out.

    My 2 bits on the subject, hope this helps and of course welcome to AK!
     

    Attached Files:

    Last edited: Nov 15, 2018 at 11:21 PM
  8. Drew Bennett

    Drew Bennett New Member

    Messages:
    3
    Wow! Thanks for everyone who replied! I’m going to repair it. I’ll be replacing the electrolytic capacitors and those noisy transistors.

    Thanks again,

    Drew
     
  9. audiojones

    audiojones Jonesin' for audio Subscriber

    Messages:
    7,170
    Location:
    Central NJ
    Hey before you go through all that have you tried other "known good" tapes? Just asking because a defective tape can cause these issues too (especially stuff like Sony PR-150 which is known to dry out and cause squealing noises, and not always in both channels). Also make sure the heads are spotless with no trace of gunk on them. I've had a lot of recorders come through here that have had sticky shedding tape run through them leaving gunk deposited all over the heads and tape path causing all sorts of problems.

    One last thing, try playing back a tape with the record inputs disconnected from the source. Sometimes a dirty contact on the relay for the record oscillator circuit can prevent an incoming signal from being shunted to ground and it can show up as a garbled crackly distorted mess being printed over on your tape as it plays. Unplug the record inputs and turn the record volume to zero to eliminate that suspect, use a good tape to eliminate the other suspect. Just puttin' it out there, simple stuff first.
     

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