The Glorious Tascam 424mkIII

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I can’t help myself. It’s a problem.

Yeah the issues with the AT-RMX64 are scant user community and technical support. It’s getting harder and harder to find qualified people to work on any analog tape machine, and I feel like there are more and more people selling machines as “serviced”, but they don’t know what they are doing. And the AT-RMX64 is among those machines that are extra hard to find qualified support because the service manual and schematics are unobtanium.

I had a client bring in a 244 recently that was “serviced”…transport rubber was supposedly replaced…they did replace the belts and reel table drive tires with proper parts, but didn’t do any of the proper disassembly, cleaning, lubricating and necessary transport adjustments after replacing the rubber parts. They also used one of those horrible replacement pinch roller donuts…the cheap-o option. As a result the headblock assembly was not adjusted…did not have the correct travel cycle, and the pinch roller rotated eccentrically, which caused a significant wow issue. The new drive tires were only partially effective because the tables and drive mechanism were not cleaned of the old gooey rubber. So FFWD and REW didn’t work correctly. Also, as a result of the removal and reinstallation of the transport, the pitch control assembly was reinstalled incorrectly and the pitch control knob would barely turn. Last but not least the -12V audio power rail was faulty, but whoever did the work decided to ignore the loud hum in the outputs, and multiple non-functional busses/outputs. And that was “serviced.”

Back to the AT-RMX64…I want clarify I typically have disdain for equipment that is either wholly unreliable, is not something I can easily service (like stuff that utilizes anything more than a minimal amount of surface-mount tech for instance…I don’t like working on the surface-mount stuff…I can do it, but my aging eyes are making it harder and harder), or for which there is extremely dismal community support or absence of available tech docs. The AT-RMX64 fits solidly into that last category…and I went to great lengths to try and locate tech docs for it…even have an inside contact at AT-USA and they couldn’t find anything. And AT-JAPAN may or may not have access to something, but their corporate liability policy prevents them from dealing with consumers. I was even willing to sign a hold-harmless agreement that would exonerate their liability in any case AND gag me from sharing anything they shared with me with anybody else. I even sent them an example. This was ultimately a successful tactic in similar circumstances trying to get ahold of tech docs for the TDK Lambda power modules that are used in the power supplies for my Studer console. But no luck with Audio Technica. So…why am I all gushy about the AT-RMX64? Because the AT-RMX64 is a rare instance for me where the kit is *so* cool I knuckled down and reverse-engineered the thing in order to repair what mine needed, and also to be able to fully calibrate it. So that puts me in a position to be able to service it and have some decent working knowledge of how power and signal and logic flows and what and where circuit blocks reside. This helps me feel less intimidated about the notion that, eventually, something obscure will fail, but I likely will be able to repair it. And, yes…people are asking silly money for some of this stuff these days. The point I want to make to you in all this is if there is something with which you are familiar, and it’s functional, it’s wise to consider the value of those factors…keep them in the forefront. I support you sticking with your Revox. I don’t know what model machine you have, but as I’m sure you know Revox is the consumer division for Studer, and the stuff is well-built. And of course typically revered. So…thumbs up from me on your decision.
I can’t help myself. It’s a problem.

Yeah the issues with the AT-RMX64 are scant user community and technical support. It’s getting harder and harder to find qualified people to work on any analog tape machine, and I feel like there are more and more people selling machines as “serviced”, but they don’t know what they are doing. And the AT-RMX64 is among those machines that are extra hard to find qualified support because the service manual and schematics are unobtanium.

I had a client bring in a 244 recently that was “serviced”…transport rubber was supposedly replaced…they did replace the belts and reel table drive tires with proper parts, but didn’t do any of the proper disassembly, cleaning, lubricating and necessary transport adjustments after replacing the rubber parts. They also used one of those horrible replacement pinch roller donuts…the cheap-o option. As a result the headblock assembly was not adjusted…did not have the correct travel cycle, and the pinch roller rotated eccentrically, which caused a significant wow issue. The new drive tires were only partially effective because the tables and drive mechanism were not cleaned of the old gooey rubber. So FFWD and REW didn’t work correctly. Also, as a result of the removal and reinstallation of the transport, the pitch control assembly was reinstalled incorrectly and the pitch control knob would barely turn. Last but not least the -12V audio power rail was faulty, but whoever did the work decided to ignore the loud hum in the outputs, and multiple non-functional busses/outputs. And that was “serviced.”

Back to the AT-RMX64…I want clarify I typically have disdain for equipment that is either wholly unreliable, is not something I can easily service (like stuff that utilizes anything more than a minimal amount of surface-mount tech for instance…I don’t like working on the surface-mount stuff…I can do it, but my aging eyes are making it harder and harder), or for which there is extremely dismal community support or absence of available tech docs. The AT-RMX64 fits solidly into that last category…and I went to great lengths to try and locate tech docs for it…even have an inside contact at AT-USA and they couldn’t find anything. And AT-JAPAN may or may not have access to something, but their corporate liability policy prevents them from dealing with consumers. I was even willing to sign a hold-harmless agreement that would exonerate their liability in any case AND gag me from sharing anything they shared with me with anybody else. I even sent them an example. This was ultimately a successful tactic in similar circumstances trying to get ahold of tech docs for the TDK Lambda power modules that are used in the power supplies for my Studer console. But no luck with Audio Technica. So…why am I all gushy about the AT-RMX64? Because the AT-RMX64 is a rare instance for me where the kit is *so* cool I knuckled down and reverse-engineered the thing in order to repair what mine needed, and also to be able to fully calibrate it. So that puts me in a position to be able to service it and have some decent working knowledge of how power and signal and logic flows and what and where circuit blocks reside. This helps me feel less intimidated about the notion that, eventually, something obscure will fail, but I likely will be able to repair it. And, yes…people are asking silly money for some of this stuff these days. The point I want to make to you in all this is if there is something with which you are familiar, and it’s functional, it’s wise to consider the value of those factors…keep them in the forefront. I support you sticking with your Revox. I don’t know what model machine you have, but as I’m sure you know Revox is the consumer division for Studer, and the stuff is well-built. And of course typically revered. So…thumbs up from me on your decision.
 

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The first pic is at 25%, the second at 50% of actual resolution. Service and parts list for the AT-RMX64.
Includes Block Diagrams, parts lists, and circuit board blueprint/x-ray/scans with part symbols superimposed for the entire machine.
Plus there is the two page typed out "Alignment Procedures", as well as a twelve page "How to" pamphlet for recording procedures.

BTW, I'm doing my own "scanning", because it's a 'buck a scan' at a retail store, and it'll be over 150 pages when all is said and done.
I'm just getting started, it will take days... also not sure of the best way to share so many large files, but I will share with all who need it.
 

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O…

M…

G…

So schematics too??

Let me know if I can help in any way.

Unbelievable…thank you.

The Raiders reference is hilarious, BTW.
 
I use WeTransfer or Dropbox for sending large files. If it makes it any easier for you, you could email pdf chunks to me and I can assemble into a single file and host on my website…just an option. PM me if you want to collaborate. Thanks again.
 
It contains the whole kit and caboodle...! There are double page foldouts for the schematics and circuit board layouts, along with complete parts lists, with prices in Yen!
I must say, getting a setup together, to photograph these is proving to be a challenge - A. keeping the long folded pages down under glass, B.maintaining even lighting, and without reflection - then it will all have to be cropped etc. We'll workout how you want me to end it once I get into it (still haven't taken the book apart yet, perfecting the setup first)
It'll take some time, but I'm on a mission, just as you were getting your AT back in shape... I only wish I had found your videos earlier so that you could have had all this info from the get go.
 
It contains the whole kit and caboodle...! There are double page foldouts for the schematics and circuit board layouts, along with complete parts lists, with prices in Yen!
I must say, getting a setup together, to photograph these is proving to be a challenge - A. keeping the long folded pages down under glass, B.maintaining even lighting, and without reflection - then it will all have to be cropped etc. We'll workout how you want me to end it once I get into it (still haven't taken the book apart yet, perfecting the setup first)
It'll take some time, but I'm on a mission, just as you were getting your AT back in shape... I only wish I had found your videos earlier so that you could have had all this info from the get go.
Sent you another PM. Thanks.
 
In case anybody lands here in the future and is wondering about the Audio Technica AT-RMX64 technical/service documents, I’ll be posting updates to this in my thread dedicated to the AT-RMX64 found here:

https://homerecording.com/bbs/threads/audio-technica-at-rmx64-story….419129/

HUGE thanks to @oddiosmith for 1. a gracious willingness to benevolently serve the AT-RMX64 community by sharing the documents, 2. taking on the work to convert the hard copies to digital, and 3. allowing me to have some part in helping!
 
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