2" Tape 16 track help?

[iomegaman]

that is an optical disc, not magnetic. the red and white wires to to LED and phototransistors on both sides of it.

on a Stephens that disc on the underside of the turnaround idler is where all the speed data comes from for control. Here is could be either speed or simply tape location. don't know yet.

so if I understand correctly, the left capstan is the shaft of the large pulley under the deck that should have the belt to the blue motor. and the right capstan is driven by a small belt on the upper portion of the shaft.

Mostly except backwards...all of these last few pictures are from the FRONT of the machine...so picture = "Flywell right head roller" is the capstan roller that connects to the shaft on the blue Honeywell motor (last seen in last pic) via a flat belt (I assume since it is missing)...it in turn is connected to the left capstan by a round rubber belt that is present...

I think I'll dig up my logitech USB camera and connect it to the laptop so I can get better pictures from inside...all of these are done on my iphone and its not so easy with my glasses to focus at weird angles...

 

[waltzingbear]

Here is what I think you have.

The blue motor is the capstan motor, the encoder on the bottom is used in some sort of control loop for better speed (ie PLL)

That is coupled by a flat belt to the capstans thu the right shaft and pulley, the left capstan is driven indirectly with a belt from the other shaft.

The optical disc at the turnaround idler is used for tape location only.

the geared motor drives levers that activate the pinch roller mechanisms.

not clear if or how tape tension is controlled.

 

[iomegaman]

Here is what I think you have.

The blue motor is the capstan motor, the encoder on the bottom is used in some sort of control loop for better speed (ie PLL)

That is coupled by a flat belt to the capstans thu the right shaft and pulley, the left capstan is driven indirectly with a belt from the other shaft.

The optical disc at the turnaround idler is used for tape location only.

the geared motor drives levers that activate the pinch roller mechanisms.

not clear if or how tape tension is controlled.

That makes a lot of sense, so the two direct motors on the reel hubs are just for additional tape consistency?

 

[waltzingbear]

I don’t understand that statement. The reel motors are there too supply and take up the tape.

normally there is some sort of control on the voltage or current through those motors. Making it either a constant torque or a constant tension situation. Not sure how this is addressed in this machine.

good luck finding a belt for this thing. It Hass to be absolutely flat the whole circumference including the joint. Otherwise there’s a big speed blip when it goes over the motor pulley.

 

[iomegaman]

So further "deconstruction" to get to the heart of the beast:

The capstan motor is a Pacific Scientific (Formerly Micro Switch) 2vm61-000-2 DC motor...runs on 18-30 volts DC...I pulled it out and put on the test bench with my 20 volt DC supply, fires up and spins...there were no power leads connected to the DC nubs on the motor...so I will have to track down the PSU DC portion and test it...this motor is the blue one that spins the right side capstan (which belt drives the left side at the same time)...it has the Sequential Information System shaft encoder attached to it via a rubber sleeve which had three leads from it going to a bus connector...which in turn is connected to a Xentek XPX20-5w that I pulled the AC leads and tested it outputs 7.22 volts DC into the Sequential Information Shaft encoder.

 

[waltzingbear]

Bump???

 

[bgaullier]

Well no I have not sent them off, but I did physically inspect them with a jewelers loupe there's virtually no wear on them.

I suspect the belt not being there is the main reason for that.

The transformers look exactly like the Urei transformers from a Mod One...at least the line transformer did...the can transformer is not one I've seen before.

Came out of a Studio in Phx. and apparently was in the Rumbo Recorders studio prior to that...at least thats the history as related to me, who knows for sure.

I took a look at your story. Nice adventure !
The 3M central transport mechanism was used of course by 3 M but also by STEPHENS who manufactured dedicated multitrack.
Quite rapidly 3M considered STEPHENS as a concurrent and was unhappy with this cooperation. For this reason 3M stop delivering transport.
Since 1971 STEPHENS build his own transport with this so peculiar central mechanism. All electronic boards was proprietary design of Stephens Electronics.
STEPHENS used 3 M transport in 1969 to 1971. After 1971 it is a Stephens Electronics design.
Stephens stopped in 1982.
Stephens machines were really interesting.
Hope this will help
Best regards

 

[dale116dot7]

Yes, the Stephens system was a bit odd, it was a two motor design. The circuitry basically measures the tape speed using the idler and an optical pickup below it, and steers torque between the two reel motors. The reel motors are set up to tension the tape as the diameter of the tape pack changes, and then at a fairly high bandwidth, modulate the torque to the two reels to adjust the speed. The brushed DC motors needed to be very smooth, as any additional flywheel mass to try to smooth out the motor’s torque just inserts a delay into what is pretty much a PID controller. The 821B and some late examples of the 811D (with three optical pickup sensors) work pretty well, the earlier ones don’t have tape direction sensing and are a bit more finicky. I’ve reworked the controls on mine and a small handful of others with brushless motors and new encoders, basically as some of the parts were custom made by John, and I don’t care to make that exact part again, updating the design seemed logical.

 

[iomegaman]

Thanks for this ino...I've seen similar stuff online...
Currently I have gotten a trove o manuals or some MCI's and Sony's that seem to have similar design...I've been going through the MCI JH24 mnuls and there' a lot o the design that seems to match stuff in the Bouse...
Also been using the variac to slowly restore the big caps in PSU...
There's a lot of reverse engineering going on and finding data sheets on older parts has proven to be rather tedious...

 

[iomegaman]

Here's the latest...weather finally approved of taking this thing outside where I could maneuver and crawl around it...lots to document but this week I've managed to pull out the power supply...holy moly its quite heavy...

Testing caps before I fire it up...had several blown fuses which appear to be either the wrong type or inconsistent at best...
The vertical fuse bank has 4 good ones and 2 bad and both of the bad ones are AGC3 250v whereas all the good oes are AGC5 32 volt...the top fuse is a MDL 10 and appear to be good...
Caps are friggin pricey...the 2 large Sprague Powerlytic 36DX's are 75000 uf 25v nd run about $104 on Digikey...Yikes!
There are a couple of bus inline fuses o the back panel that are labelled "Audio +15v/4.5A & Audio -15v/4.5A...the -15v is blown...

So gonna test the caps...maybe try reforming them at least once...

There is also a separate smaller PSU that provides power to the small capstan motor I've previously tested the motor nd I think it needs like 18volts don't remember gotta check my notes...

 

[iomegaman]

Here' the creepy crawly underbelly...

 

[iomegaman]

It dawns on me none of my LCR meters go up to 75000 uf...sheesh...

 

[EmilFrid]

It dawns on me none of my LCR meters go up to 75000 uf...sheesh...

Wouldn't it be better to just recap the whole psu? Awfully expensive if done all at once (referring to the figures you cited) but maybe you could spread it out a bit, changing them all over a longer span of time. If you need the machine functioning asap, that wouldn't work though...

By the way, this thread is so exciting. I'd love to spend a few romantic nights with that machine. It's s3xy as hell! A truly unique piece of history. I will follow this with great interest.

Good luck!

 

[iomegaman]

Yes it would be best to recap the psu...the Sprague 36DX's are pricey best price to replace all the 36Dx's is around $400...but I've found 75000 uf 25 volt for much less...(large can computer grade for about $14.00...here)....so maybe not using the Sprague Powerlytic 36DX's....I can do it for half or less...

Not sure what the difference is between the Sprague 36DX's and "computer grade"...gotta research.


(Just as a "what the everlasting F?", Mouser wants $222 per 30,000 uF/40v caps...that makes the replacement cost closer to $800 YIKES!)

 

[EmilFrid]

That's a  much nicer price. I did a quick search, since I'm unfamiliar with the term "computer grade", but it seems like a good candidate, maybe you found this already:

"Power electrolytic capacitors or computer grade capacitors, as they have been traditionally called are a good choice for applications that require large capacitance or a high voltage. They are aluminum electrolytic capacitors that are offered in a can with screw terminals. As the name “computer grade” implies this style of capacitor was originally designed for main frame computers because of their long life and high ripple characteristics. These same characteristics have proven to make them a popular choice in designing power supplies, welding equipment, communications systems and in automotive applications."

From Computer Grade Capacitors.

 

[iomegaman]

By the way, I just bought a flyer for $20...thats dumb, but in researching I found out that the first model of this machine was called the "Pro Master 16"...


(top left paragraph)

...and yes this thing weighs about 300 lbs...UNLOADED.

 

[iomegaman]

So I've obviously never worked on a 16/24 track tape machine but I have rebuilt quite a few consoles with their big power supplies, but this psu is unlike anything I have ever seen...in that last set of pics in image 1204/1208 you see a heat sink with a built in fan on the end...that is for the rectifier diodes...there's about 8-S3720 Silicone Power rectifiers on the bottom that are rated for 85 amp average forward current that connect to the Torridial Tranx inside the black box on top...then they run speaker wire to the 75,000 uf/25v caps...(testing the rectifier circuit I get around 17-18volt dc into the cap wires unloaded...)

I understand the roller motors might need a few amps...and the tranx is rated at 1.5 ARMs...single phase I've never encountered an ARMS rating...I suppose the audio cards and rec cards might require a decent current reserve...but this thing seems way over built...NFPA Type II fire rating...I'm beginning to think Mr. Bouse designed stuff for the Aerospace industry...

 

[MidnightArrakis]

So I've obviously never worked on a 16/24 track tape machine but I have rebuilt quite a few consoles with their big power supplies, but this psu is unlike anything I have ever seen...in that last set of pics in image 1204/1208 you see a heat sink with a built in fan on the end...that is for the rectifier diodes...there's about 8-S3720 Silicone Power rectifiers on the bottom that are rated for 85 amp average forward current that connect to the Torridial Tranx inside the black box on top...then they run speaker wire to the 75,000 uf/25v caps...(testing the rectifier circuit I get around 17-18volt dc into the cap wires unloaded...)

I understand the roller motors might need a few amps...and the tranx is rated at 1.5 ARMs...single phase I've never encountered an ARMS rating...I suppose the audio cards and rec cards might require a decent current reserve...but this thing seems way over built...NFPA Type II fire rating...I'm beginning to think Mr. Bouse designed stuff for the Aerospace industry...

1.5ARMS = 1.5 Amps RMS (Root Mean Square)

I had purchased several 33,000uF capacitors for an audio power-amplifier project and I -- think -- the price was maybe $8.00 each or so. I will need to search and scrounge around on my hard-drive to try and find the receipt for that purchase. However, the main difference between the capacitors that you need and the ones that I had purchased are that mine were PCB-mount instead of "screw-terminal" connections. But, they were still BIG "MUTHA'S"!!!

In somewhat related news.....should your project here ever happen to need something "rebuilt" (as in -- "made again") or any of the PCB's "re-done" (as in -- re-designed over again to be made as "new").....just let me know, OK??? I have done "Reverse-Engineer" projects on both mechanical chassis and on PCB's ranging from mixing consoles to fighter jets (NO KIDDING!!!). I am always willing to lend a hand whenever needed.

/

 

[iomegaman]

1.5 RMS is kinda what I defaulted to...however the Transformer is a huge torridial that sits inside the black box case in picture 1204...it larger than the torridials in my Soundcraft 32 or Biamp 2016 consoles...and those are both around 600 watts providing at least 5 legs of 3 amp power...it seems a bit "under-rated" for what I suspect is its actual capability...but whadda I know...

I'm going to put a public folder on dropbox with all my pics if anyone is interested...
Here's the flyer I bought from evilby...

 

[iomegaman]

For anyone interested here's a link to the dropbox picture folder...about 150 pics mostly for documentation as I reverse engineer this beast...lots of redundant pics and I tried to label them for reference...

DropBox Bouse Folder