MIDI Time Control rack unit power supply

Smithers XKR

Well-known member
Hello all

Sorry if this question is a bit obscure, I am really hoping someone can help.

I am using an a old legacy system running MIDI to analogue multitrack.

I have an XRI XR300 MTC striper, the original white one. It uses a plug in 9V power supply. I lost the original adaptor so I do not know whether the polarity is centre negative or positive. There is no polarity information on the back or in the instruction manual.
I dont want to risk plugging in an adaptor with the wrong polarity in case I fry a chip.
Most units have a protection diode I know but I dont want to take the chance.
Can anyone help please? 🙁
Thanks, Smithers 👍
 

jamesperrett

Active member
Looks like you must have a prototype XR300. All the reviews I've found say that the production models have an internal power supply but one showed a white prototype. However, if it is based on the XR03, as one of the reviews said, then I found a picture of the back panel of the XR03 at


which shows

Img20509-4.jpg


So I'd guess it is the same as this. However, I'd open it up and check the internal connections with a meter first to be on the safe side.
 

Smithers XKR

Well-known member
Looks like you must have a prototype XR300. All the reviews I've found say that the production models have an internal power supply but one showed a white prototype. However, if it is based on the XR03, as one of the reviews said, then I found a picture of the back panel of the XR03 at


which shows

Img20509-4.jpg


So I'd guess it is the same as this. However, I'd open it up and check the internal connections with a meter first to be on the safe side.
I dont have a meter and have no manual skills to open it up. A simple musician I am... but.. I do have a little electronic knowledge.
From what I can see that looks like centre positive, can you confirm this please James? Yes I do have the original white proto without the internal DC voltage converter, so I have no reason to believe XRI would change the polarity.
Thanks mate made my day buddy 🥰🥰👍👍👍
 

Smithers XKR

Well-known member
Looks like you must have a prototype XR300. All the reviews I've found say that the production models have an internal power supply but one showed a white prototype. However, if it is based on the XR03, as one of the reviews said, then I found a picture of the back panel of the XR03 at


which shows

Img20509-4.jpg


So I'd guess it is the same as this. However, I'd open it up and check the internal connections with a meter first to be on the safe side.
PS I am being a stingy bastard on a budget now ha ha. I have a centre positive 9V adaptor which provides 0.5 A current. The unit draws 800mA. I am suspecting it will run on this but the adaptor may run hot and go bang in time but as long as the unit remains ok?
 

Smithers XKR

Well-known member
Looks like you must have a prototype XR300. All the reviews I've found say that the production models have an internal power supply but one showed a white prototype. However, if it is based on the XR03, as one of the reviews said, then I found a picture of the back panel of the XR03 at


which shows

Img20509-4.jpg


So I'd guess it is the same as this. However, I'd open it up and check the internal connections with a meter first to be on the safe side.
It powers up and seems to all work great with all of the functions and the centre positive 9v 500mA adaptor. It is said to draw 800mA at peak current so the only thing that can possibly go bang is the power supply overheating which I dont care about and not an issue without any possible damage to the XR unit. Thanks James, you are a superstar for this info.
Cheers mate 🥰😉👍
 

jamesperrett

Active member
Good to hear it all works. To be on the safe side I'd go onto the CPC website and order one of their TT Electronics universal supplies which are really handy to have around. They're only about a tenner and can supply up to 1.5A.
 
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