Page 1 of 2 1 2 LastLast
Results 1 to 10 of 20

Thread: Tascam 388 adjustments

  1. #1
    Join Date
    Mar 2011
    Posts
    37
    Thanks
    0
    Thanked 2 Times in 1 Post
    Rep Power
    0

    Tascam 388 adjustments

    Sign in to disable this ad
    Hi all,

    I've owned a Tuscan 388 for a while. It is still fully functional, but I want to take the leap into adjusting and calibrating the machine. I'm going to start acquiring the necessary items, but had a few questions first. Quick note, I'm pretty new to this so I'll be learning as I go.

    I've adjusted the tension arms a few times in the past - most recently the right arm when I was getting extremely slow playback. I noticed this most recent time the adjustment trim pot for the right tension arm would no longer turn clockwise, like it was turned as far is it would go. Is there a way to adjust this? Is it simply a matter of contact cleaner, or does it need to be replaced?

    Secondly, I would like to adjust the VU meters. But I'm wondering how this will affect the tapes I've already recorded on the machine.

    Lastly, is this a decent multimeter for the general tape maintenance purposes? I've found one used locally.

    https://simpsonelectric.com/images/F...heets/2608.pdf

    I know there's a bunch here.

    Thanks in advance.

  2. #2
    Join Date
    Mar 2011
    Posts
    37
    Thanks
    0
    Thanked 2 Times in 1 Post
    Rep Power
    0
    So a little follow up. I should have researched the multimeter ahead of time. I ended up buying a Leader LMV 181A. It still needs to be shipped. I do have one question about the machine though. Do you know what kind of probes are compatible with this machine? It does not come with any. I have a very cheap digital multimeter with red and black probes - would these work?

  3. #3
    Join Date
    Apr 2008
    Location
    Pacific Northwest, USA
    Posts
    8,553
    Thanks
    223
    Thanked 218 Times in 198 Posts
    Rep Power
    3753124
    Cheap digital multimeter with standard probes will work fine for measuring DC volts, but won’t work for accurate measurement of AC audio voltage across the audio spectrum. For measuring frequency response ya need a true rms measuring ac voltmeter that is reasonably accurate from 20Hz to 20kHz. I use a Fluke 85. It’s okay. Gets the job done anyway but there are much better meters out there.

    To your earlier questions, calibrating the VU meters has no impact on the levels of signal going to tape or coming off of tape or monitored at the input. Calibrating the meters simply makes it so when the meter reads 0VU with a 400Hz tone input (I think I’m remembering right the reference tone on a 388 is 400Hz), the amplitude of the tone is -10dBV, or 316mV AC. It makes it so what the meters show you is calibrated to a known signal and level.

    What trim pot are you adjusting for the takeup tension arm? Can you post a pic? Have you looked at the trimmer? Does it look corroded? You can try sweeping the trimmer back and forth to see if that improves things. If sweeping it doesn’t help, and you are adjusting the right trimmer, it’s not usually a problem with the trimmer, but either something else out of adjustment, or a component failure around the trimmer. It’s important you follow the steps in the manual exactly as the are, included preceding adjustments. You can end up chasing your tail because (for instance) maybe the tension seems off but you haven’t first checked and adjusted the brakes. Or if we are talking PLAY mode maybe the pinch roller needs replaced, or pinch roller pressure needs adjusted, or the capstan belt is slipping. I’d go that route first before assuming there is a problem with the reel servo board. Also, what kind of tape are you using?

    Can you post a video of the problem you are having with the takeup tension?

  4. #4
    Join Date
    Mar 2011
    Posts
    37
    Thanks
    0
    Thanked 2 Times in 1 Post
    Rep Power
    0
    Thanks for the reply, Sweetbeats. I'll have a lot to look into. I was hoping to use some holiday downtime to dig in and gain as strong an understanding of this machine as I can.

    Regarding the Leader LMV 181A, I believe it fulfills the requirements you've mentioned. I'm mostly just curious about what probes I'll need to purchase to get the meter functional. Here is a link to the manual:

    http://bama.edebris.com/manuals/leader/lmv181a/

    With the tension arm, I'll have to check it out when I get home from work. I followed the procedure from this link:

    Tascam 388 Maintenance, Repair and FAQ thread - Message Board

    Essentially, I lined it up according to the description. It actually went just that far then maxed out, maybe a hair under what is described in the post. It was enough to get the Tascam to play and record.

    I have a small collection of tapes, but mostly I've been using NOS Maxell 35-90, Quantegy 457, and occasionally Scotch 207.
    Last edited by illuminations; 12-22-2017 at 12:32.

  5. #5
    Join Date
    Apr 2008
    Location
    Pacific Northwest, USA
    Posts
    8,553
    Thanks
    223
    Thanked 218 Times in 198 Posts
    Rep Power
    3753124
    The Scotch 207 may be sticky-prone. Refer to the sticky-shed thread at the top of the forum. I can’t remember off the top of my head.

    That voltmeter looks like it will work fine as far as accuracy.

    I’m not sure I’m clear about what the quandary is with what probes to get. Can you link some examples of probes you are looking at so we can quantify your options? Probes are probes...you need probes. Get probes. Throw up some links and maybe I’ll better understand what quandry is.

    And let’s back up on these test procedures...you DO have the Operation - Maintenance manual, yes? That should be your #1 reference source for servicing your 388, and in the order the tasks are laid out in the manual...there’s two main chunks that comprise servicing your tape machine: 1. Transport checks and adjustments, and 2. Recorder/reproducer electronic checks and adjustments. The 388 of course has a 3rd chunk that being the mixing section electronic checks and adjustments, but that’s of lesser interest or concern usually. So, you first get the transport dialed in, and then proceed to the tape machine electronics (the “alignment”), but it is very important you follow the order of the different steps and components of each chunk.

  6. #6
    Join Date
    Mar 2011
    Posts
    37
    Thanks
    0
    Thanked 2 Times in 1 Post
    Rep Power
    0
    The Scotch 207 is fine, I think. I'm pretty meticulous about clearing the heads/tape path when I use the machine. There is rarely more than a speck or two when I use the machine.

    Regarding the probes. I think I was thrown off because the probes I have for the digital voltmeter have sheath that goes over the banana plug, which is not compatible with the Leader voltmeter I bought. I guess I'll just have buy new ones without the sheath.

    I am going to wait to use it though, and heed your advice to go through the transport adjustments first. A few of the adjustments call for a spring scale. Would either of these be suitable for the tasks?

    American Weigh Scales - Digital Scales Wholesale

    Feedback Sports Alpine Digital Scale | Competitive Cyclist

    These were both referenced in other forums, but in regards to different tape machines.

  7. #7
    Join Date
    Apr 2008
    Location
    Pacific Northwest, USA
    Posts
    8,553
    Thanks
    223
    Thanked 218 Times in 198 Posts
    Rep Power
    3753124
    Quote Originally Posted by illuminations View Post
    The Scotch 207 is fine, I think. I'm pretty meticulous about clearing the heads/tape path when I use the machine. There is rarely more than a speck or two when I use the machine.

    Regarding the probes. I think I was thrown off because the probes I have for the digital voltmeter have sheath that goes over the banana plug, which is not compatible with the Leader voltmeter I bought. I guess I'll just have buy new ones without the sheath.

    I am going to wait to use it though, and heed your advice to go through the transport adjustments first. A few of the adjustments call for a spring scale. Would either of these be suitable for the tasks?

    American Weigh Scales - Digital Scales Wholesale

    Feedback Sports Alpine Digital Scale | Competitive Cyclist

    These were both referenced in other forums, but in regards to different tape machines.
    Okay on the Scotch 207. Keep in mind tape that is going sticky won’t necessarily shed, but may bind on the tape path causing over-tension. Just keep it in mind. I’m assuming you are having the same problem with the take-up tension arm regardless of what tape you are rolling though, yes?

    And on the probes yes I see what you mean now...yes you’ll need some sort of probe with an exposed banana plug on one end to connect to the combo terminals on the Leader.

    And regarding the spring scale, the one you linked might work, but I don’t know what the minimum measurable weight is and how fine the gradient is on the display. There are typically two things you use spring scales for on a tape machine: calibrating the brakes, and calibrating the pinch roller pressure. The two tasks call for different weight ranges...the brake adjustment procedure often measures in ounces, while the pinch roller pressure procedure is orders of magnitude more weight, usually pounds. So I have two spring scales with each with a different range. I use Ohaus scales. I think these are pretty common for our purposes here.

    OHAUS | Spring Scales

    So, again, that digital one might work just great, I’m just not familiar with it (but haven’t been in the market for a spring scale in about a decade), and you just want to look in the 388 manual to see what ranges you need to cover and the measuring accuracy and then cross reference that with the digital scale’s specs and see if it’s a match. If it works that’s great. Nice to have one tool to do the job than two.

  8. #8
    Join Date
    Jul 2012
    Location
    In the garage
    Posts
    303
    Thanks
    1
    Thanked 30 Times in 25 Posts
    Rep Power
    810094
    Unless the brakes are slipping or grabbing,you don't need the spring scales.More critical would be the tape tensions.which you need a Tentelometer to adjust precisely.
    Re.the tension arm position adjustment:as you said you can get close and that may be close enough. What has happened is component values have drifted or there is something wrong in the reel servo circuit.Also,unless you have a playback alignment tape any tape recorded on your machine will not be compatible with any other 388.

  9. #9
    Join Date
    Mar 2011
    Posts
    37
    Thanks
    0
    Thanked 2 Times in 1 Post
    Rep Power
    0
    I finally had a chance to try the trim pot again tonight. I noticed something this time that I didn't notice the first time. The top of the trim pot has a a ring with a little tab on it. There is a little metal piece that prevents this tab from moving fully. In the picture below the trim pot on the left is for the right tension arm. It is turned as for clockwise as it will go because that metal tab is being obstructed. Does that mean that this can't be adjusted any further? Seems kind of strange. It's pretty much in place now, but I think it would be better if it was just a hair higher.
    Attached Thumbnails Attached Thumbnails tension-trim-pot-jpg  

  10. #10
    Join Date
    Mar 2011
    Posts
    37
    Thanks
    0
    Thanked 2 Times in 1 Post
    Rep Power
    0
    I’m wondering if the trim pots normally only need to be turned a little normally? Mine has gone fully clockwise and still the tension arm is not high enough.

    wkrbee do you think if the components values have drifted it would cause there to be an inconsistency in the tension? Maybe this is forcing the trim pot to overcompensate?

    I have a spare machine. I’ll try to swap the reel servo card in the next few days to see if that helps things. Do you think it would be a matter of changing the caps? I’ve considered doing this throughout my second machine slowly over time until I’ve done them all anyway.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Adjustments to Vocal?
    By Dr.Reign in forum MP3 Mixing Clinic
    Replies: 1
    Last Post: 09-18-2014, 23:04
  2. How I Record Guitar - EQ Adjustments
    By STAT1STICK in forum Guitars and Basses
    Replies: 0
    Last Post: 03-14-2014, 13:34
  3. Truss rod adjustments...? maybe?
    By Dogbreath in forum Guitars and Basses
    Replies: 23
    Last Post: 02-17-2010, 10:25
  4. Any EQ adjustments that you *always* make?
    By DM1 in forum Mixing Techniques
    Replies: 12
    Last Post: 04-06-2006, 08:08
  5. Neck adjustments
    By SSgtP in forum Guitars and Basses
    Replies: 13
    Last Post: 03-07-2002, 10:07

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •