Tascam 238 Syncaset | First Impressions, Tear Down & Repair.

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My first impressions of the 238. This unit was sent to me for repair, as well as basic cleaning lubrication and alignment/calibration, signal path electrolytic capacitors were replaced on two of the eight amplifier PCBs to resolve low recording levels on two tracks. I wanted to get the unit back to the customer ASAP, hence everything being jumbled together in one long video!
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TETRAKAN - Fix & Use Tape Recorders
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...covering every cassette multitrack recorder ever made!*
*(eventually)
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CHAPTERS
0:00 Introduction
2:00 First impressions - front panel
5:21 Rear panel
8:09 Looking over the User manual
9:17 Source tape switching & insert button
10:55 counter units & TRT tape run time
11:05 External synchronisation
11:26 MIDI & FSK frequency shift keying
11:39 Tape sync & filter switches
12:15 Caveats regarding the recording of sync data
13:21 Computer control via SMPTE
1400 Serial port & bps rates
15:11 Tape speed vs tape run time etc
15:42 User pitch control
16:13 Rack ears - my thoughts on the format
16:49 Multi region voltage
17:23 Frequency response, Dynamic range & signal levels
17:45 Official accessories
18:05 skimming over the service manual
18:52 Trimpot locations
19:09 Contrast & compare build with 234 and 488
20:00 Deciding what to do next
20:37 First test
23:18 Shuttle control silliness
23:40 Results after adjusting playback amps
24:58 Aligning meters & testing record amplifiers
25:48 Remove upper case
26:47 Safety precaustions
28:11 Remove amplifier PCBs
31:16 Remove cassette player
34:34 First look at cassette mechanism
36:35 Access Idler tire & pinch roller for cleaning
40:09 Idler tire and pinch roller sizes
40:55 remove front panel & access shuttle controls
43:45 Access control boards, meters, counter switches etc.
45:34 Mother, power supply & rear switch PCBs
47:56 Replacing electrolytic capacitors on faulty amplifier PCBs
49:12 results of repair & conclusion

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Опубликовано:

12 июл 2024

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Комментарии : 29

@DaveZula 4 месяца назад

I will never stop being amazed to see you completely tear apart a machine like this and put it back together again.

@Tetrakan 4 месяца назад

I played with Lego a lot as a child

@drfonta 3 месяца назад

I have two of these. The better (less use) one is for sale on Reverb. I've replaced most of the Electrolytics caps and replaced all the caps on the capstan board as well. Calibrated and sounds fantastic for a cassette 8 track.

@johntammaro 4 месяца назад

This looks like a beast of a unit. Looking forward to your tear down and review.

@VultureCulture 4 месяца назад

Whenever I see there's a new Tetrekan video I know it's going to be a good day!

@Tetrakan 4 месяца назад

You flatter me. I won’t lie, I like it.

@wehappyfewmusic 4 месяца назад

Great to see the process of this getting repaired and you’ve also explained what some of mysterious buttons on the control panel do! I feel a similar way about all the midi sync stuff but must give it a try it out at some point. Thanks again for fixing this unit and I’m delighted to have a working 238 again! 🙌🙏

@Tetrakan 4 месяца назад

Someone commented about seeing two of these synced by computer as a 16 track - I wondered if that'd be possible with this unit and your 688, I forget whether the 688 has SMPTE control as well?

@wehappyfewmusic 4 месяца назад

@@Tetrakan I saw that comment too and have been wandering if it’d be possible all afternoon. I’d love to have a go if so and was planning on asking you for some advice! 🙏😊

@DigitalFacts 4 месяца назад

Got three of them and one Dolby-S version a few years back when no one wanted them and kicked them out. Repaired them (especially the capstan board on all units needs attention). The Dolby-S version was unrepairable till this day because of some faulty dolby chips. What a beauty of engineering art! :)

@Tetrakan 4 месяца назад

Have you seen the site 238pro.com? I’ve only skim read it but there was information about getting the Dolby version working up there. I’ve come to prefer the less obtrusive and coloured sound of Dolby NR to DBX, so having that NR on an 8 track with my studio master 16/ mixing desk sounds like peak cassette recording tech

@DigitalFacts 4 месяца назад

@@Tetrakan No I didn't know the site even exists. Thanks for letting me know! Will check the information on there regarding the Dolby-S problem.

@Ejlectronics6 4 месяца назад

How funny, I've got one sitting on my bench too! Yet to crack into it might go in blind first ;)

@Tetrakan 4 месяца назад

Much nicer to work on than that 234 you shared on Instagram, doable with no scouting from me I'd say

@valleywoodstudio7345 4 месяца назад

Excellent stuff - interestingly my old Fostex E 16 does not advertise in the manual (or the front panel) that it has anything but a global Dolby C defeat switch - yet when you open it up and get access to the channel cards there are defeat switches for track one and track 16. I'd assume they kept it simple for most users, but more discerning 'pros' if asking the dealer would have been supplied the information. Separate note (please excuse this off topic to the video) - I've a Fostex 250 that I'm using with students and owned since 1988, and have been going through the maintenance manual to bring it all up to spec - which it nearly is - and found the ferrrite screw for the channel one Dolby encode circuit is missing! It still seems to function fine on primary record passes (does not like excessive transient materiel on a bounce to track one though) as the inductor only sets a minimum bias point for that section, according to the manual Just wonder if possible you may have something that may go in there if you have scrap spares etc - and if so best way to contact?

@Tetrakan 4 месяца назад

I don’t have a scrap 250, unfortunately ,….for the sake of one channel could you house an extant part of equivalent value on a little Vero board baghterboard and use hookup wire to manage any difference in footprint?

@valleywoodstudio7345 4 месяца назад

@@Tetrakan Thanks. Sadly that may be the case - I've scoured old radios etc to see if I could find a similar screw to no avail.

@valleywoodstudio7345 4 месяца назад

@@Tetrakan I managed to source one from TascamNinja - he had the exact part so all sorted

@drfonta 3 месяца назад

Bias setting question. I was having a hard time getting the bias setting just right. Manual calls for same level of 1k and 10k. Can be time consuming for sure. I tried sending 1k then 10k, playing it back and seeing the difference then tweaking R62 again and again. Then I decided to try recording a dual tone 1k and 10k, then looking at it on the spectrum analyzer making it easier to see how far off I was. Saved a lot of time and I got them dialed in tight now with a nice flat frequency response. Do you have any tips on how to do this better? Thanks for the great video BTW!

@Tetrakan 3 месяца назад

With a open reel system with 3 heads it’s much easier to set bias because you get slightly delayed feedback from the repro head on what the trimpot adjustment is doing. The compromise I use with two head systems is to record a vocal narration of the position of the trimpot on an adjacent track to the test tones with a microphone, so my voice will say stuff like “fully counter clockwise, 20 degrees higher, twenty degrees higher, halfway,…..” and so on. Then playback both recordings, listening to my voice while observing the meter behaviour for the test tone. It’s still a PITA compared to setting up the same thing on a three head system but you get some sense of where the needle peaks and how far to go beyond that for an appropriate level of over-bias.

@BolognaFullof 4 месяца назад

question: how easy is it for me to replace the belt in my Fostex X12? i'm nervous about tearing it open and would like some suggestions on how to approach it

@Newmusicreview Месяц назад

Hi bud....I just got one of these but as usual the motor sounds like a small jet engine...tapes plays / FF / REW but stops randomly frequently....what would you suggest first step ?

@aronslegogbcs1057 4 месяца назад

wow, what a deck, i would love one for my colection just cause it looks cool, could the speed be changed to 1/78?

@Tetrakan 4 месяца назад

There’s a tiny trimpot on the capstan motor board marked 4.8 which I assume means it could be calibrated for the lower speed, though I guess that’d require some modification, I didn’t have time to look into it properly.

@frequincyrecording4286 4 месяца назад

I’ve seen video of 2 of these units synced together using that serial port, but I don’t recall what device accessory was used. I assume one tape was stripped with SMPTE.

@Tetrakan 4 месяца назад

As mentioned in this video, I’m normally a bit of a sceptical curmudgeon when it comes to to sync stuff, but the idea of a cassette based 16 track does sound exciting - please post a link here if you find the video again?

@frequincyrecording4286 4 месяца назад

Both tracks 8 were striped with SMPTE from the Tascam ATS-500. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-UNGRONFxoc4.htmlsi=lGeYfY3dcwoNtZsK