Tascam Portastudio 424 Mk I - Channels "dropping out" in playback - please advise

[Beardmoss]

Tascam Portastudio 424 Mk I - Channels "dropping out" in playback - please advise

-I also posted this in the Tascam forum but read I may get more engagement here-

Hello,

I own a second hand Portastudio 414 Mk I, which served me well while recording a project recently. However, it's time to do a mixdown, and I've noticed a concerning problem.

At random moments certain channels suddenly lower in volume. Usually it's just channel 2. It drops to "very quiet" for a while, then slowly comes back up to normal volume. I know this is a playback problem and not on the actual recording, as it happens at unpredictable moments.

My band's songs are 7-10 minutes in length, so I dread the prospect of running the signal out to the master tape, then all of a sudden at 8 minutes in a channel drops out.

Is this a common issue? Is this something I could fix myself? I have very limited mechanical/electronic experience but my gut feeling is that a connection somewhere is compromised. There is an a/v service place in town but I know the tech has a huge backlog and I'd like to also avoid the $75 it might cost me (which is what I paid for the machine in the first place).

I appreciate your input!

 

[Gtoboy]

My 424 has never had this issue so I cant say for sure though I would suggest deoxit cleaning of sockets, faders, pots , etc and cleaning and demag the heads and transport. Anyone else have any info?

 

[RFR]

First off, a THOROUGH cleaning of the heads is advised. With that narrow width, its amazing how little dirt can ruin your day.

I've had heads that looked clean yet the playback volume was funky. Cleaning and cleaning again brought it back to normal.

I can't say if this is your culprit, but it's a basic remedy to apply.

If it doesn't solve your issue at least you have removed one non optimal issue.

Can't hurt to try.

 

[Beardmoss]

Thanks guys, I previously demagnetized the heads and cleaned the heads and rollers, shocked at how much crap came off, but I will clean them again after reading this. I haven't done a deoxit cleaning, that's one of the things I was hoping to find out about how to tackle this. Is there a forum thread about cleaning the pots etc? I just want to make sure I'm doing things right.

 

[RFR]

Plenty of info in the analog section. Lots of tascam 4track threads. Get some coffee, tea, whiskey or whatever and start reading.

 

[Beardmoss]

I'll take all of the above! Cheers!

 

[ourshape]

Tascam Portastudio 424 Mk I - Channels "dropping out" in playback - please advise

-I also posted this in the Tascam forum but read I may get more engagement here-

Hello,

I own a second hand Portastudio 414 Mk I, which served me well while recording a project recently. However, it's time to do a mixdown, and I've noticed a concerning problem.

At random moments certain channels suddenly lower in volume. Usually it's just channel 2. It drops to "very quiet" for a while, then slowly comes back up to normal volume. I know this is a playback problem and not on the actual recording, as it happens at unpredictable moments.

My band's songs are 7-10 minutes in length, so I dread the prospect of running the signal out to the master tape, then all of a sudden at 8 minutes in a channel drops out.

Is this a common issue? Is this something I could fix myself? I have very limited mechanical/electronic experience but my gut feeling is that a connection somewhere is compromised. There is an a/v service place in town but I know the tech has a huge backlog and I'd like to also avoid the $75 it might cost me (which is what I paid for the machine in the first place).

I appreciate your input!

Hi, I'm having this exact issue now and am wondering if you ever found a solution? I've looked everywhere and can't seem to find one.

 

[sweetbeats]

Check if the same issue is present when monitoring via the TAPE OUT jacks, the TAPE CUE buss, and when you set input channels 1-4 to source TAPE. If it is the last one, it could be the channel source select switches. The quality of the source select switches dropped drastically with what I call the “plastic” generation of Portastudios…424/464/488/644/688 machines. Don’t get me wrong, I’ve owned almost every machine in that generation and have used a 424 mkII quite a bit…but the smaller horizontal PCB-mount slide switches on the later generation machines just do not last like the large vertical mount toggle switches in the older machine (like the 244 for instance), and the solder joints are more fragile. These issues can cause random cutting in and out of signal. Try exercising the switches. It may be necessary to disassemble the unit so you can get to the switch itself and jet DeoxIT D5 or similar and exercise more and then let them dry…exercise again. If the issue happens the same at the TAPE OUT jacks as well as the TAPE CUE buss then it is something further upstream. If the dropouts can be repeated (like listen for dropouts, rewind the tape a bit and play again and if the dropouts occur in the same spots/same way) then the dropouts printed to tape during recording and it’s an issue on the input/record side. So check those things out and report back…maybe we can hone in on where/what to look at. Also…what tape are you using? And is the transport clean? What does it look like in there on the guides and the heads? What’s your cleaning regimen and what products are you using? It takes almost nothing as far as debris to interrupt signal…like a speck of something almost too small to see when you’re working with multitrack cassette. If the tape is old/bad or the tape path is dirty with oxide or dust/dirt that’s all it could take to cause trouble.

 

[ourshape]

Check if the same issue is present when monitoring via the TAPE OUT jacks, the TAPE CUE buss, and when you set input channels 1-4 to source TAPE. If it is the last one, it could be the channel source select switches. The quality of the source select switches dropped drastically with what I call the “plastic” generation of Portastudios…424/464/488/644/688 machines. Don’t get me wrong, I’ve owned almost every machine in that generation and have used a 424 mkII quite a bit…but the smaller horizontal PCB-mount slide switches on the later generation machines just do not last like the large vertical mount toggle switches in the older machine (like the 244 for instance), and the solder joints are more fragile. These issues can cause random cutting in and out of signal. Try exercising the switches. It may be necessary to disassemble the unit so you can get to the switch itself and jet DeoxIT D5 or similar and exercise more and then let them dry…exercise again. If the issue happens the same at the TAPE OUT jacks as well as the TAPE CUE buss then it is something further upstream. If the dropouts can be repeated (like listen for dropouts, rewind the tape a bit and play again and if the dropouts occur in the same spots/same way) then the dropouts printed to tape during recording and it’s an issue on the input/record side. So check those things out and report back…maybe we can hone in on where/what to look at. Also…what tape are you using? And is the transport clean? What does it look like in there on the guides and the heads? What’s your cleaning regimen and what products are you using? It takes almost nothing as far as debris to interrupt signal…like a speck of something almost too small to see when you’re working with multitrack cassette. If the tape is old/bad or the tape path is dirty with oxide or dust/dirt that’s all it could take to cause trouble.

Hi, thank you so much for the reply I'm going to try out all of the above but as far as what I've done already is cleaned heads and path with 99% Isopropyl Alc and I've also taken the thing apart to check connections and things but I have not used Deoxit on anything. If I remember correctly, the dropouts did seem to occur in the same spots but I will double check this to be 100% certain. As far as the tape I'm using it's brand new maxell XL II 90 minute cassette. I'll go ahead and clean it once more later today as an interesting thing is when I began recording about a week ago there wasn't nearly as noticable an issue, if any, when I was recording and playing back but maybe even the next day or two the issue presented itself. Thanks for all the advice and I'll test and report back when I do.

 

[sweetbeats]

“Brand new” XL II tape or new old stock?

And the 90 minute tapes *should* be okay? But note the specified tape length is 60 minutes. I’m not positive if there are any 90 minute tapes that use thinner tape stock or if that is only when you get up into the 100, 110 and 120 minute tapes.

It might be worth getting an actual new late manufacture tape to test assuming the Maxell tape you are using is new old stock…if so that’s 40+ years old by now and who knows the storage conditions.

 

[ourshape]

“Brand new” XL II tape or new old stock?

And the 90 minute tapes *should* be okay? But note the specified tape length is 60 minutes. I’m not positive if there are any 90 minute tapes that use thinner tape stock or if that is only when you get up into the 100, 110 and 120 minute tapes.

It might be worth getting an actual new late manufacture tape to test assuming the Maxell tape you are using is new old stock…if so that’s 40+ years old by now and who knows the storage conditions.

That is interesting I’m not sure if it’s brand new or new old stock as I ordered it from Amazon. Is there anywhere you suggest that I could get actual new tape not old stock and hopefully the 60 minute length?

 

[sweetbeats]

Okay everything I see on Amazon is definitely NOS (refers to being ideal for recording from Compact Disc, for instance), but I was thinking of UD XL II, not the later XL II and XL II S. Those tapes are probably 30-35 years old. They are probably fine. And I *think* 60 and 90 minute cassettes use the same tape stock. So it’s probably fine. I guess just keep in mind just because it’s new tape doesn’t mean it’s good.

Yeah after doing a quick search it looks like new type II 60 minute cassettes are hard to come by. If you can find TDK SM60 tapes those are my favorite and are a newer production tape. Not current by any means but good quality and significantly newer than the Maxell XL II tapes. The Maxell was/is good quality though. But yeah it’s like $10-15 a tape…crazy. I was just suggesting trying to get ahold of *something* truly new to help rule out if your Maxell tape is part of your issue…it’s probably not and I don’t want you to spend money on a goose-chase. It’s just where my brain goes as a troubleshooting step and I have the advantage of having a good quantity of different tapes here…if I was having your problem I’d just grab a different tape and test it out…no change? Not the tape…on to the next step, etc.