Hi,

I want to run a Tascam 112MkII pro audio cassette deck from a precision linear bench psu (not yet purchased) to undertake a scientific task, but don't know how it could be connected. Can anyone advise me?

I have two groups of wires coming off the pcb upon which the transformer sits. One is labelled "to Cont M PCB" (5 wires) and the other "to Main PCB" (4 wires).

 

really clear pictures of these boards would help a lot, at this point we can only assume.

 

Hi,

I want to run a Tascam 112MkII pro audio cassette deck from a precision linear bench psu (not yet purchased) to undertake a scientific task, but don't know how it could be connected. Can anyone advise me?

I have two groups of wires coming off the pcb upon which the transformer sits. One is labelled "to Cont M PCB" (5 wires) and the other "to Main PCB" (4 wires).

That unit requires 120V AC. Is the unit not in the case?

http://tascam.com/content/downloads/products/322/112mkII-TechDoc.pdf

 

really clear pictures of these boards would help a lot, at this point we can only assume.

Maybe I am a little premature - I haven't got photos at the moment as I am awaiting delivery of the unit.

I was hoping to upload the Service Manual but the file size is too big, and the zip size is no smaller.

Page 1/11 shows the power supply arrangements.

I will try to think of something else.

 

That unit requires 120V AC. Is the unit not in the case?

http://tascam.com/content/downloads/products/322/112mkII-TechDoc.pdf

I am in the UK and shall be using 230VAC.

The idea is to replace the unit's own transformer with a better external supply.

 

Why do you want to this? This look like a pro unit. So it should have a good power supply inside. I might be wrong here. But perhaps using a good sound card on a PC is a better option

 

Here is a jpg screenshot of the power schematic.

 

Why do you want to this? This look like a pro unit. So it should have a good power supply inside. I might be wrong here. But perhaps using a good sound card on a PC is a better option

Thank you for your reply.

The normal power supply generates a line frequency magnetic field that radiates into the unit's playback head and circuitry, which is what I want to avoid.

 

You can get transformers that convert 230 volt to 120 volt or the other way. I am quite sure your school have some. If not they are not so expensive for then you do not need much power. Like in a cassette deck

 

You can get transformers that convert 230 volt to 120 volt or the other way. I am quite sure your school have some. If not they are not so expensive for then you do not need much power. Like in a cassette deck

I think you have misunderstood - this is not a school project.

 

Here is a jpg screenshot of the power schematic.

Looking at the diagram it supplies AC to the main pcb for some reason, so running it from a DC supply is of no use, why dont you remove the transformer and place it external if its buzzing?

 

Looking at the diagram it supplies AC to the main pcb for some reason, so running it from a DC supply is of no use, why dont you remove the transformer and place it external if its buzzing?

I know that it can be done as there is a company who adapts the 122 model in the way that I am attempting.

As I said initially, I am engaged in a scientific project and require the enhanced performance of a low noise and ripple linear DC supply.

 

I know that it can be done as there is a company who adapts the 122 model in the way that I am attempting.

As I said initially, I am engaged in a scientific project and require the enhanced performance of a low noise and ripple linear DC supply.

Have you contacted this company? If they know how to do it, ask them or buy their technology. I'm a super-noob but I can tell you that what you want to accomplish will be pretty difficult (and seems counterintuitive me).

Good luck with your experiment.

 

Have you contacted this company? If they know how to do it, ask them or buy their technology. I'm a super-noob but I can tell you that what you want to accomplish will be pretty difficult (and seems counterintuitive me).

Good luck with your experiment.

It would be indiscreet to ask the company to reveal their design technology, and their modified deck retails at $5950.

I bought mine at a fraction of that amount. If I can work out how to run it off a high end PSU I will have saved a lot of money.

 

It would be indiscreet to ask the company to reveal their design technology, and their modified deck retails at $5950.

I bought mine at a fraction of that amount. If I can work out how to run it off a high end PSU I will have saved a lot of money.

There appears to be a DIP switch in your schematic that allows operation from 230v. Have you tried that?

 

There appears to be a DIP switch in your schematic that allows operation from 230v. Have you tried that?

The internal circuit voltages are the same for all the line voltage varients - be it US, Euro or UK, so if I bypass the standard transformer it will not matter. The AC line voltage ends at the PSU.

 

Here is a copy of the Tascam 112Mkii power supply schematic.

As far as I can identify, there are two outputs +12VDC and -26VDC, but I have no idea what voltages "F" and "P Down" are, or indeed what they represent.

 

Hello,

Ususaly F is an AC voltage used for a filament.
Is there a tube (valve) in the recorder?
It could also be for a VFD display.

Bertus

 

Hello,

Ususaly F is an AC voltage used for a filament.
Is there a tube (valve) in the recorder?
It could also be for a VFD display.

Bertus

I am afraid that I do not know.

 

Hello,

According to the connections in the powersupply there could be a VFD display in the recorder.
Have a look at this page for more info on the display:
http://www.noritake-itron.com/SubPages/ApplicNotesE/vfdamapn.htm

This is one of the links from this EDUCYPEDIA page:
http://educypedia.karadimov.info/electronics/tubevfd.htm

Bertus