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Power supply recomendation for Thandar TD201

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prof328

Member
Hi all, I have just bought a Thandar TD201 digital storage unit, but it came with no power supply.

I think it needs between 4V and 10V dc.
Before I buy a wall wart supply I would be grateful for some advice.
1) Does it matter if the supply is switching or regulated
2) Is it a standard plug arrangement where the centre pin is positive.
3) What voltage would you recommend
Typical power consumption for the unit is 500mW.
Thanks.
 

spec

Well-Known Member
Most Helpful Member
Any 4V to 10V, 1A or more DC supply will do. It does not matter if the DC supply is linear or switch mode. I would recommend a 9V 1A or over supply, but a 5V, 1A or over supply would also be fine.

The center pin or tip of the connector is positive.

spec

PS: I have both the TD201 instruction and service manual if you want them.

2016_06_03_ETO_THANDAR_TD201_DIGITAL_STORAGE_UNIT.png
 
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prof328

Member
Thanks for the advice spec, I have already downloaded the user instructions and service book in pdf format, but thanks for the offer most generous.
Being new to all this and at the lower end of the "steep" learning curve I found the diagram for JK1 confusing, as the V shaped connection I would assume to be the ouside contact of the plug but it is connected to the positive side of the battery ??
 

spec

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Hy prof,

No probs- why they can't specify exactly what the tip or center polarity is in the documentation I just don't know. You get this all the time, but it is fairly standard these days for the tip or center of the plug to be positive. Note that there are two types of connector, jack and barrel. I don't know what type of power socket is on the TD201.

No, the V shaped part on the schematic connects to the positive tip or center on the plug. The bar shape connects to the part of the plug barrel closest to the plug self-lead (0V). The circuit symbol is confusing.

spec

PS: we have relations over the bridge at Aberdare and my misus is half Welsh- not sure which half though. :)
 
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prof328

Member
Thanks again spec I've learnt a tiny morsel more on how to read diagrams.

I'm English but moved here with my job, been here 30 years and no plans to move, retired now and live in a little village.
 

spec

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Thanks again spec I've learnt a tiny morsel more on how to read diagrams.

I'm English but moved here with my job, been here 30 years and no plans to move, retired now and live in a little village.
We wouldn't hold it against you if you were Welsh. :)

North Wales is nice, I spent some time in Prestatyn.

spec
 

prof328

Member
We wouldn't hold it against you if you were Welsh. :)

North Wales is nice, I spent some time in Prestatyn.

spec
Hey spec,
Haha, I like the Welsh nothing wrong with them at all, I was just clarifying that I'm not.;)
Prestatyn is on the coast, I live south east of Wrexham in the countryside, nice and quiet:D
prof328
 

spec

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Nice area- pretty close to civilization over the border.:p I have been to Wrexham a few times. My mother-in-law lost her best cardigan through the hole in the floor of our mini van while we were driving through Wrexham in the early 1970s. She wasn't too amused when I said that it was a shame she wasn't wearing it at the time.:D

spec
 

JimB

Super Moderator
Most Helpful Member
The center pin or tip of the connector is positive.
Normally I would agree with you, but...

No, the V shaped part on the schematic connects to the positive tip or center on the plug. The bar shape connects to the part of the plug barrel closest to the plug self-lead (0V).
I am not convinced, and will wear sack cloth and ashes if I am wrong, but,
I think that the V shaped bit contacts the outer sleeve of the connector, and the "Bar" is the pin which enters the barrel of the plug.

The circuit symbol is confusing.
That is so true!

JimB
 

prof328

Member
Oh crap now I'm in a quandry, the last thing I want to do is to connect it with reverse polarity.
I need someone who has one of these to test their supply plug with a multimeter and let us have a definitive answer.
 

spec

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Most Helpful Member
Hy Jim,

It is not clear if the Thandar TD201 has a jack or barrel connector which adds a bit of confusion.


Normally I would agree with you, but...
Agree, but going by the PSU circuit diagram the center or tip is positive

I am not convinced, and will wear sack cloth and ashes if I am wrong, but, I think that the V shaped bit contacts the outer sleeve of the connector, and the "Bar" is the pin which enters the barrel of the plug.
It depends if the connector is a jack or barrel.

On a jack, the V can either engage in the indentation at the back of the tip or on the main barrel.

With the barrel the V can only contact the outside barrel but that is physically; the contacts can be isolated.

That is so true!
It is a nightmare, especially as there are four main sizes of jacks and N sizes of barrel connector: diameters both inner and outer and even different lengths.:arghh:

spec
 
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JimB

Super Moderator
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Why don't you simply open up the case of your TD201 and have a look?
Use a multimeter to measure what is on the terminals as they are?

Looking at the PSU schematic which spec has provided, the -ve side of the battery connects to one of the connector terminals. Check it out.

JimB
 

spec

Well-Known Member
Most Helpful Member
Oh crap now I'm in a quandry, the last thing I want to do is to connect it with reverse polarity.
I need someone who has one of these to test their supply plug with a multimeter and let us have a definitive answer.
Don't worry. I am pretty sure I am right, but in any case it wont matter if the polarity is reversed, you won't do any damage because there are two diodes in the PSU to protect against reverse connection. If you could tell us what connector you have: jack or barrel, that would be a big help. Can you take a large picture of the power connector on the instrument.

spec
 

prof328

Member
OK so why didn't I think of that - doh.
There are four batteries in a carrier, they are used to retain the data in memory.
The power connector is of the barrel type but a little bit smaller in diameter than the most popular ones.
The multimeter shows the negative side of the battery is connected to the central pin of the socket and the positive is connected to the side sleeve of the socket.

So I need a power supply 9V 1amp with a negative central socket of the plug, is that correct ?
 

spec

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Most Helpful Member
OK so why didn't I think of that - doh.
There are four batteries in a carrier, they are used to retain the data in memory.
The power connector is of the barrel type but a little bit smaller in diameter than the most popular ones.
The multimeter shows the negative side of the battery is connected to the central pin of the socket and the positive is connected to the side sleeve of the socket.

So I need a power supply 9V 1amp with a negative central socket of the plug, is that correct ?
From what you have measured, yes but that does not accord with the circuit diagram. Your best bet is to get a PSU that can be switched betwen positive and negative inner. You can also get a PSU with a wide range of connectors. I will have a look for a suitable unit

spec
 
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JimB

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Most Helpful Member
So I need a power supply 9V 1amp with a negative central socket of the plug, is that correct ?
Yes, when you say it quickly, but why not find a PSU, find a plug, and fit the plug to the cable of the PSU?
Maybe easier than finding a readymade PSU with the correct plug.

yes but that does not accord with the circuit diagram.
At the risk of being controversial, I think it ties up exactly with the (ambiguous) circuit diagram.

JimB
 

prof328

Member
The user instructions leave a lot to be desired, the instrument is portable and can be powered by four C size batteries, the batteries can be either disposable or rechargeable, and there is a selector switch on the rear.
The instrument may be powered by an approved AC adapter/charger.
If using rechargeable batteries and the selector switch set to rechargeable the power supply will recharge the batteries at a rate of 170mA.
If using disposable batteries and the selector is set to disposable inserting the power jack will automatically disconnect the batteries.

It's just confusing to me.
It would be really nice if someone who has one of these to take a picture of the label on the power supply as this would surely show all the information needed.
 

spec

Well-Known Member
Most Helpful Member
At the risk of being controversial, I think it ties up exactly with the (ambiguous) circuit diagram.
I have seen the light. Nice one Jim. :banghead: Please send sack cloth and ashes.

spec
 
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JimB

Super Moderator
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If using disposable batteries and the selector is set to disposable inserting the power jack will automatically disconnect the batteries.
Ahh, I was wondering what the DISP annotation was about next to one of the switches in the schematic.
All is revealed.

:banghead: Please send sack cloth and ashes.
This is like these charity bags wanting old clothes, which get put through my letterbox from time to time.
Do they not realise that that is what I am wearing most of the time?

JimB
 
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