Tascam 112B Motor Questions

[rtp_burnsville]

Hi Guys,

Tonight I dug into my Tascam 112B and have a few questions. I believe the capstan motor is trashed but have a couple questions:

1)Does anyone have a clue as to what the color code of the capstan motor wires are? The motor is a Sanyo marked with SHW2L, 00-0206A. It's a CCW rotation motor and I believe it is 12 volts. There are two pairs of wires Orange and orange with black marks, the other pair is yellow and yellow with orange marks.
2)The yellow pair runs to a PCB labeled PCB 52101958-00, Teac, AP42S. This looks like a power supply board as the large filter caps have roughly 17 volts across them. Would anyone have a schematic for this board??? There looks to be a sense resistor of about 10 ohms on the high side but I don't understand the return portion of the circuit. The are a couple other resistors and caps on the pcb but not exactly sure what their purpose is at the moment.
3)The orange pair runs to the area of the pitch control switch and pot.
4)My guess is two wires are power so are the other two wires an encoder or sometype of feedback?
5)I would test the motor stand alone but really would like to understand the wiring scheme before letting the magic smoke out.

Does anyone know of a source for the above motor or something which may work? I searched around the internet a bit but did not find much of anything.

Does anyone have a schematic which could help?

Thanks,
Robert

 

[laatsch55]

The man you need is Sam Palermo, AKA Skywavebe. I'll rattle the bush.

 

[laatsch55]

The Hounds have been released!!!!

 

[Fast Forward]

post a Pic of the motor Maybe I have a one from a donor unit,,FF

 

[rtp_burnsville]

Here is a photo of the motor....

Thanks,
Robert
[attachment=0:3nlpr233]Img_0469_a.jpg[/attachment:3nlpr233]

 

[Fast Forward]

let me do some scrounging this weekend

 

[Skywavebe]

Hello Robert,
I have been crazy busy with repairs and so have not had a lot of time to look over my three or four forums. Well I am here now. I have one of these in my shop now. The motor was taken apart and the brushes were so worn they broke off as they were touched.
These motors are not high end by any means. The motor type that can be substituted is the Mabuchi 4 terminal CCW 12 volt type servo motor but from most places these have been sold out. I think a compatible one is the EG530AD-9B. Studio Sound Electronics used to have motors like this. The pitch control board is nothing fancy. It has a switch and a couple of LED's and then a temperature comp resistor and then a pot. There has been at least one modification to the board resistor value wise due to a sub'ed part for the motor.
Here is a schematic of the 112 deck, it is probably the same unit except the 112B has a balanced converter section built in. The rest may be the same. See Pdf attached.

 

[Skywavebe]

Hi Robert,
I did a search of motors on E bay and some from China where they are made came up rather cheap.
You can do a search of the model in this auction as well to find the one of your liking.
See item # 250818233840.

 

[rtp_burnsville]

Thank You Sam!!!

I ordered two motors this morning, can't wait for their arrival. Thanks for the schematic as that was a big help. I now understand what is going on without having to retrace the pcb's. The current motor is junk as it's drawing way to much current as that 10 ohm 1/2 watt resistor is showing about 2.5 Watts!!! That is more than enough to reflow the solder joints, yikes!!!! Hopefully this will get the deck back in shape shortly.


Many thanks guys!

Robert

 

[rtp_burnsville]

Hi,

Thought I would post an update on this project being FF asked in a different thread. The motors arrived this week so early this morning I dug into the Tascam. Got everything apart then it turned interesting, always does at some point......

First, was that tiny setsecrew on the capstan motor pulley. I have a basement filled with most every tool imaginable but not a micro-miniture, metric allen key so the pulley is still on the original motor. Monday will order a microset from McMaster Carr and hope one fits!

Second, The new motor has four holes for wires all is good, NOT! The motor is not the same as the original but I think I will be able to get single speed operation once the above pulley issue is solved. The new motor has the 4 holes wired in parallel (2 for positive and two for negative) the original has two for positive and negative and two for what looks like speed control. It looks to me like the current Tascam speed control circuit would not work with this motor (Thanks Sam for the schematic). I took the original motor apart and the bearings are shot and I also managed to break the brushes as well so it's now toast. Once I got the original motor apart I can see that there is some control electronics inside that I am pretty sure is very different than the new motor. If I get a few minutes I'll reverse engineer the original internal motor circuit board to see if I can see what it's doing.

Anyway, I put everything back together (less the motor pulley, I can still get to that) and powered it up just to see what would happen. I think there is hope for single speed with no pitch control. The one thing is I need to check is if the new motor allows one to adjust the speed via a pot in the back of the motor.

FWIW, the Nakamichi is a whole lot easier to work on.... Oh, I only have one extra screw, and I haven't a clue where it goes!!!!! After spending most of the day messing with this I am at the Panera having coffee!

Good Afternoon,
Robert

 

[speakerman1]

Wow I just remembered I have a Tascam 302 parts deck I haven't opened yet. It supposedly works. The 302 has trim also. I might have a motor. Sorry I just remembered that.

Larry

 

[rtp_burnsville]

Original motor markings:

[attachment=2:1x5f6d5p]Img_0502_rs_orig.jpg[/attachment:1x5f6d5p]


Original Inside:

[attachment=1:1x5f6d5p]Img_0500_rs_bearing.jpg[/attachment:1x5f6d5p]


New Markings:

[attachment=0:1x5f6d5p]Img_0505_new_marking.jpg[/attachment:1x5f6d5p]

 

[rtp_burnsville]

Ha, everything I do turns into an adventure......

I usually learn a bunch along the way which makes it fun!

 

[laatsch55]

If its not fun, ain't worth bein done!

 

[Fast Forward]

is it silver or black

 

[Skywavebe]

Hi Robert,
The motors I bought fit perfectly. What motor type or model did you get?

 

[rtp_burnsville]

Hi Sam,

They physically fit, it's the four wire connection which appears to be different from the original.... The original has -,+,H,L while the new only has -,+ (see photos above) Here is what I bought:

EG-530AD-2B DC 12V CCW DVD Player Micro Electric Motor
250818233840

Did I mess up and get the wrong ones???

Thanks,
Robert

 

[speakerman1]

Main motor PN 9278365900 Tascam number
Reel motor PN 9278365700 Tascam number

Do any of these numbers work for you? If so let me know and I'll pull it.

Larry

 

[rtp_burnsville]

Larry,

thanks, I'll check the numbers......

Today I reverse engineered the original circuit board in the old motor and now understand how the speed control really works. If someone wants to know the details let me know and I'll write up a description. It's rather interesting as the original motor contains an internal speed control IC. The extra two connections (marked H and L) on the motor allow access for the motor speed to be controlled via external resistor values. I even found the datasheet on the internal control IC and the sample application circuit in the data closely mirrors what Tascam used in the 112 cassette deck.

The new motors I have with only two connections will work fine (single speed only) but one no longer would have a speed control option (pitch control) from the front panel. If I get a few minutes I might break apart a new motor and see if one can fish a couple wires out to regain the external speed control option.

A rather cool adventure this has been now that one understands what is going on..

I also ordered a set of micro size hex keys so I can get the pulley installed and give the deck a test spin. Thanks everyone for all the help!

Robert

 

[rtp_burnsville]

Hi Larry,

The only numbers I can find on my original motor are:

SHW2L
00-0206A

I doubt they are the same, but thanks for checking.

Robert