Tascam 488 Mk 1 & 2 | poor playback levels - SOLVED - 2 screw fix

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After a lot of wild theories about why my Tascam 488 was playing back a test tape much quieter with the case closed than with the case open, the solution turned otut o be really simple and dumb - i only had one of the two screws inside the cassette cavity in place! Inserting a second screw mitigated the problem. The same issue will apply to 646 and 488 MK II as well since those models have these cassette cavity screws.
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Опубликовано:

15 авг 2022

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Комментарии : 32

@recursivedeleteaudiovisual Год назад

That particular screw size is M2.6 x 8. 👍

@Tetrakan Год назад

Thanks Jack!

@johnuhmmmiles Год назад

Hey there tetrakan, quick question if you have a minute. I followed your video on changing gear c, and that did the trick on getting the cassette moving and the play/pause/stop buttons working. However, now the issue I have is that I don't seem to be getting any sound out of the inputs. Neither XLR or 1/4 inch produce any volume. Also, the output from my tape (with music already recorded on it) only sends out a very very low volume. Is this a wiring issue perhaps? Or something needs to be cleaned? I am a bit of an amateur, but I don't think it has to do with my tape cue or grouping settings. Thanks for your videos -- they've made this process much easier for me!

@Tetrakan Год назад

No sound whatsoever from any input would lead me to suspect the power wasn't reaching that part of the circuit. That could be something unplugged, bad caps, bad solder, damaged cable, really you'd need to get in therexwith a DMM and an audio probe and diagnose. Low playback level - adjusting the gain on the playback amplifier trimpots could do the trick but sometimes it will be down to the same issues - power not reaching opamps, audio going to ground through leaky caps or not passing properly through leaky audio path caps, bad cables or solder creating more resistance to the audio signal than bother circuit designers intended, etc.

@syntholabo Год назад

Posting here as it’s your latest video, and your ABOUT page says you prefer to answer queries in comments. Can you do anything with a Revox B77 that needs love?

@Tetrakan Год назад

I don't think I'd better. I'm a reel to reel virgin and I'm up to my eyeballs in cassette stuff still!

@syntholabo Год назад

@@Tetrakan haha! Thanks for getting back to me. It’s a beast that was so fine once upon a time. Can’t bring myself to throw it out. It’s there if you wanted to experiment. I’m probably close to ya at EH postcode ;)

@Tetrakan Год назад

Don’t throw it out! At the very least it has parts value so you should eBay it….but yeah it was my intention to look at R2R stuff on a timescale of EVENTUALLY so if you didn’t mind it being here in a get around to it one day pile potentially for years I’m in Edinburgh occasionally to see friends and could pick it up. Do you have fb messenger so you could contact me about this there?

@TheEnd10026 Год назад

Would you be able to fix a tascam 424 thats not recording on track one and has a problem with the rca outs?

@Tetrakan Год назад

Where are you based?

@TheEnd10026 Год назад

@@Tetrakan United States.

@Tetrakan Год назад

I'm in the UK but I can put you in touch with people your side of the pond if you're willing to ship within the US? If so msg me on Facebook

@TheEnd10026 Год назад

@@Tetrakan Thank you I will Dm you.

@Eywalian Год назад

i have a 424 mk1 that has a poor playback level on track 1 only, would you have any leads of what i should look for to fix it?

@Tetrakan Год назад

Try turning up the playback amplifier gain trimpot as described in the service manual. Failing that, replacing the coupling capacitors in the playback amplifier audio path often yields improvements. If you look at videos I've made with "colour coding schematics" etc in the titles, you'll get more information.

@Eywalian Год назад

@@Tetrakan thank you! ill try that

@LIQUIDAETHERAudio Год назад

Hey mate, my 488 MK2 has some signal fluctuations (level and frequency) on Track 1; on one new cassette it even had nearly zero signal on that track. I did some deep cleaning of the tapeheads and I can't say if it had theses fluctuations before since I got it with abroken C-Gear and can only now start testing it in practice. Do you have any suggesttions on how to fix that? By the way thank you for showing us how to change the C-Gear! Much appreciated!

@Tetrakan Год назад

Sounds like the edge of the tape is rubbing against something in the tape path, most likely the metal tape guides attached to the heads themselves. This creates level pitch problems on tracks 1 or 8 because those are the tracks physically closest to the edges of the tape. You might need to adjust the azimuth so the tape doesn’t rub against the guides.

@LIQUIDAETHERAudio Год назад

@@Tetrakan Thanks! Do you have a video on how to adjust the Azimuth?

@Tetrakan Год назад

@LIQUIDAETHERAudio not yet. But the instructions are in the service manual, which is available for free download from my blog. In your case its more a matter of adjusting the screws (or is it Allen keys on that model? I forget...) just enough so the tape goes past the heads etc without rubbing against anything. If you can buy a tape path checker at a reasonable price or build one (Its a blank cassette with a small mirror build into it at 45 degrees so you can see how the tape interacts with the heads and so on) that'd be helpful.

@LIQUIDAETHERAudio Год назад

@@Tetrakan It is in there? Okay, I will check the manual again. Thanks! Building a mirror Cassette seems to be a nice project and may come in handy in the future when working on other machines.

@LIQUIDAETHERAudio Год назад

@@Tetrakan Track 1 of my 488 just 'died'. Overnight, and before I even started to adjust the azimuth or playhead etc. I recorded an SR-16 Drum testsignal yesterday and it showed no flaws anymore, but this morning the track went silent. Signal is coming in, but playback shows no sign of life anymore. Do you have an idea what this could be?