Tascam M-___ Story...

[A Reel Person]

You are an Animal! Gearslutz rejoice! Here's our Mentor!

Heh, heh......

Hey, that's a pretty sharp and impressive looking board! Fully loaded, no doubt.

I guess you got more than you were bargaining for in the Master section! Blecchh! Did I have to view that with my morning coffee? Aaaggghhh!!!

All those nifty PCB's and no formal part numbers? Screw holes scribed and drilled by hand? Of course it's a prototype, now c'mon!

Not just a prototype, but IMO a legitimate piece of history!

Too bad I missed you on the Burbank run. It would have been fun to meet you down there for the pickup. Plus, there's Pro-1 AV, a great recording specialty shop down there that I could've shown you! Well, next time!

Question: If I decided to give up all my gear, would you come down with a U-Haul and pick it up??? Never mind, I think I know the answer!

 

[cjacek]

[insert applause]

Cory, just wanted to second Dave's emotion! Hear, hear!!

--

 

[sweetbeats]

I guess you got more than you were bargaining for in the Master section! Blecchh! Did I have to view that with my morning coffee? Aaaggghhh!!!

I seriously did LOL on that one!

Yeah, I debated...the rodent defication is pretty old I believe, but that didn't stop it from glistening in the light from the flashbulb in the second picture did it?!?



I pulled the channel 1 module apart completely last night and took stills of each side of each PCB...indeed there are no part numbers!

I'll put shrinky-dink versions of them up here with a link to the full-size versions. Any comments on them would be fully welcome.

Dave, I did think about trying to hook up with you while I was down in your neighborhood...it was just insane though; the schedule. It was midnight when I hit Burbank and picked it up and then back on the road...lasted until over the Grapevine. I had a short window...next time, friend.

Question: If I decided to give up all my gear, would you come down with a U-Haul and pick it up??? Never mind, I think I know the answer!

Clearly, a certain amount of reasoning has left this person, but I can still calculate the area needed to haul your collection, and in doing so select the proper set of trucks to do so.

 

[cakewalkKaKed]

GREAT THREAD !!! ive just read all of it (including the start thread)...
cant wait till you get this beast fired up,and find its history !!!!

 

[sweetbeats]

Here Come The PCB's...

{cakewalk, thanks for the encouragement!}

Remember: I'm arbitrarily naming these PCB's based solely on the controls that are mounted on them.

INPUT PCB, full-size versions here and here

PGM PCB, full-size versions here and here Lookit how many open locations there are on this PCB...there were plans for other stuff methinks...

EQ PCB, full-size versions here and here

AUX/MONITOR PCB, full-size versions here and here

MUTE/SOLO PCB, full-size versions here and here

REMOTE PCB, full-size versions here and here

 

[sweetbeats]

Phew!! Its about time for a modern art break...

Okay...break's over...

 

[sweetbeats]

VU Meters...

So I mentioned a few posts back that the VU meter PCB looked very familiar with respect to my handling of the M-520 VU meters...I had hoped they were the same and then it would be safe to assume that the meter bulbs run off of an 11VAC rail like the M-520, and that information would put another puzzle piece in place with respect to building up a power supply for this mixer.

Well, they aren't the same, but much of the componentry is the same...lots of similarities, and the meters themselves are identical. I can't get to the backside of my M-520 meter bridge very well at the moment...would somebody be willing to pull the back cover off of their M-512/520 to tip a pair of meters out to see if the M-500 METER AMPL PCB is labeled "METER PCB-121" like this one here out of the M-___ mixer?

Here is the trace side of the PCB by the way...

 

[sweetbeats]

Other Activities...

I got the Mother PCB's and their frame completely out last night and cleaned that assembly up...not much to do but dust it off, really...I will apply DeoxIT on the card slot connectors when the time comes, but other than that it looks to be in really good condition.

I also took a crack at cleaning up the input module dress panel. For those of you that are familiar with the work I did on my M-520, I got those panels to look pretty good using a Finish 2000 car polish product, though the M-520 dress panels were in much better condition to begin with. I seriously wondered if the M-___ panels were actually painted with flat paint, because that's what they look like in addition to being nasty grungy...I didn't have very high hopes...I used a product called TR-3...Didn't effect the silk-screen at all and the panels are indeed glossy.

Here are some side-by-side before and after shots. They don't really do it justice. It is night and day in-person.

The next major task in sight is to clean up the main frame (which will include repainting) in order to have something in which to reinstall modules as they get cleaned up.

 

[sweetbeats]

Talked to Tascam...

Talked to Jimmy in Operational Support. He's been there for 25+ years and has always been a tremendous resource on really sticky issues in the past. He saw the pictures that shoulderpain sent and it sounds like they passed them around to all the gurus and nobody has any idea what it is...he kept saying that it might be a prototype to the M-300 or M-512...I reminded him that many of the features extend a bit beyond either the 300 or 500 series boards...I kept at that for a bit and then he said that maybe it was even a prototype for the 5000 series but I think that's off chronologically...the M-___ looks to be pre 300 or 500 because of the orange detailing on the lower trim strip...like around the time of the beginning of 38/58 production...1983? Which I guess is when the 300/500 boards started too. Hm...

Anyway, he said that Teac really doesn't maintain archives and that you would think they would but they don't. He further suggested that maybe it was custom built for a specific installation, or that it was a prototype that got stolen as opposed to being destroyed, which is the protocol...might explain the missing PS...

He had no interest in getting links to this thread and he stated that he didn't think anybody else would either...they don't know what it is so they are done with it (my interpretation).

He suggested maybe trying to contact the author of that Tascam history book...somebody had put up a link to that in some thread...Rick or Richard I think...anybody have that?

 

[cjacek]

This one?
http://www.amazon.com/TASCAM-30-Yea...=sr_1_1?ie=UTF8&s=books&qid=1223510625&sr=8-1

 

[Richard King]

Or this one???? http://www.instrumentpro.com/C-TAS-HISTORY-1

 

[Richard King]

To me that thing looks like a cross between a Model 10 and a 512. But, as I mentioned in the other thread, the fact that it is in line is totally out of character for Tascam at the time.

 

[analogkid]

I know what it is! Just like that Johnny Cash song, some former Tascam employee got it ONE PIECE AT A TIME, likely carried out in their lunchbox.....

so it's a m-300,512,5000, 30 series mixing board. We'll call it the Sweetbeats board once he gets it cleaned up


AK

 

[sweetbeats]

AK...Um...The marketing department would hate you...that'd be a Tascam M-300512500030...sweet!

This one?
http://www.amazon.com/TASCAM-30-Year...3510625&sr=8-1

Daniel, yah, that one...thanks! I want to try and track down the author and show him the M-___ board and see if he has any contacts or resources that may be able to pinpoint some more info about it. Plus, I did get a response back initially from the guy that shoulderpain got the board from and he seemed very open to sharing what he knew about it, but I haven't been able to get further than that yet...I'm hoping there might be a name or some contact info for where he got it from in hopes of getting historic info...

Richard,

Thanks for the link. That wasn't quite what I was looking for, but I've seen that info in the past and personally I don't think it can get linked enough...very interesting and valuable bits in there so thank you for taking the time to link it here.

 

[sweetbeats]

Its like a 10,000 piece puzzle of wires, traces and components...

But its fun...

I'm starting to try to map the PCB's out. I'm starting with the basics, the Mother PCB.

A couple answers so far:

• It appears that the BUSS MASTER pots on channels 1 ~ 8 do indeed source the respective PGM ASSIGN's for channels 1 ~ 12 (i.e. if you assign channel 12 to PGM 1, it will be controlled by the BUSS MASTER pot on channel 1), and those in turn feed the BUSS OUT jacks on those same channels (i.e. BUSS MASTER for PGM 1 on channel 1 feeds the BUSS OUT jack on channel 1, PGM 2 pot on channel 2 feeds the BUSS OUT jack on channel 2, etc.)
• The BUSS MASTER pots on channels 9 ~ 12 do indeed serve as the master controls for AUXes 1 ~ 4 , and the corresponding BUSS OUT jacks on channels 9 ~ 12 output AUXes 1 ~ 4 (in fact the jack PCB's are labeled BUSS (AUX) OUT for the BUSS OUT jack). Phew!
• The REMOTE switchracks on channels 1 ~ 12 (the switches by the channel faders) do source the GROUP A & B switchracks in the master section. Not sure yet about the nature of the source of the switchracks in the master section, but the REMOTE switches on the channel strips go there.
• The MONITOR switchrack in the master section is connected to the channel strips in the same way as the GROUP A & B switchracks on the mother PCB. Not yet sure how the channels access that section of the master module, but, with the GROUP A & B/REMOTE feature (and all the other stuff), this mixer has some pretty flexible and powerful routing ability.
• Channel strips and master section are chock full of TL072 IC's, I see some 4556's in there too, and a couple "MC14069UB" Motorola chips on each channel strip...dunno anything about those yet.

Fun stuff!

 

[dementedchord]

4069's are logic chips... 6 cmos inverters per package... these would mostlikely be used in some kinda group muting or similar function... ie. when a solo is hit it's signal would go high... and the 4069 would output a low... thus muting whatever... make sense???

 

[sweetbeats]

Cool-cool-cool...thanks demented!

That makes sense...especially it being a Motorola chip. I'll take a closer look at the traces.

Those chips are on the "AUX/MONITOR PCB", but I could have/should have monikered that board as the main channel board since it has all the I/O contacts on it and all the wiring is soldered to it, whereas they are almost exclusively on connectors on all the other boards on the channel...it is like the channel mother PCB...I bet when I look at it the connections from the MUTE/SOLO sections make their way to those chips.

Wow...newbie to this, but a small-format mixer with logic chips on the channels...

 

[sweetbeats]

Model 15 similarities...

Check out a pic of the back of a model 15 mixer...comments about the M-___'s similarities with the 15 are evident here for sure...sorry, the picture is kinda funky. It was a .png that I down-converted to a .jpg and lost the transparency, but I'm looking at the back of the channel strips. Identical in form and mounting to the M-___.

 

[sweetbeats]

A number of tasks have been done since I last posted:

• Disassembled the frame and scrubbed/hosed down everything to get the mouse poo/potty out of it. Everything cleaned up just fine, and in the next couple weeks I'll be getting some paint made up to match the original and repaint the parts. The front crossmember (behind the armrest) is actually in three sections that are glued together...prototype lookin' engineering...and the self-tapping screw holes that connect the side-rails to the front rail are flimsy and semi-stripped out...glue beads were run at those junctions as well. My plan is to finish cleaning the old glue out and fill the screw holes with 2-ton epoxy and then re-drill them so the screws have a new surface to tap. I'll be repainting the rear cross-member as well after I strip the rust spots off...minimal rust but there is some by the rear left corner by the back of channel one...the main bathroom.
• There were some rust spots on the back of the channel 1 frame. They were easy to remove with a small wire wheel after which I sprayed the areas with self-etching grey primer for protection.
• Cleaned up the meter-bridge housing as well. There will be some spot painting on the inside...fortunately the outside is pretty good (since the face has the graphics screened onto it...tough to repaint) except for a scratch on the top of the face and some scuffs...I think I'l be able to minimize the scuffs by polishing/waxing and I'll touch up the scratch.
• The channel 1 knob/switch caps are scrubbed clean...I've got some parts that need to be swapped for spares due to missing or damaged knobs...channel 1 and the master section seemed to have taken the most abuse in this arena, but all the push-switch covers are in extremely good condition...like new looking. I'm wondering just how much use the board has seen. It is in rough condition for sure, but I'm wondering if that has been just from getting shuffled from place to place...
• I have figured out 10 of the 12 connections on the power supply connector. The other two go to the meter bridge but also daisy chain to the master section...Since the meter amp PCB's are so much like the M-520 I'm hoping to compare one on the M-___ to the schemo for the M-520...my hunch is that, though the PCB's are different in layout, they are close if not the same schematically...that will tell me that the two leads going up to the meter bridge are 11VAC for the meter lamps, though I can't figure ou what would call for 11VAC in the master section...haven't teased that out yet. I've decided to see if I can find the female side of the Molex connector that's on the board. There's a shop locally that may have such an animal in stock or may be able to get it.
• More "10,000 piece puzzle" stuff...I'm part way done making a connection diagram for all the channel PCB's so I can know what wires from the main board go to what plugs on all the other PCB's.

 

[technoplayer]

When It Was Made>>>>>>>

Sweetbeats, this is really cool. I may be able to add a small piece of data for you.

Most of the IC chips seem to be JRC (Japan Radio Company), but one of them on the EQ pcb looks to be a Texas Instruments TL072CP Op Amp.
The date code on the chip should be in the format (YR/WK)
with the first two digits being the last two digits of the year of mfg and the last two digits being the week of the year. Unless it was replaced (unlikely), then the board could not have been produced earlier than that date, and given chip revisions and inventory turnover, probably not more than a year or two AFTER that date. At least you can narron in on WHEN this beast was built.

Keep up the good work!!!!