Alice Air 2000 PSU Transistors


Alice Air 2000 PSU Transistors

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ben
ben
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Hi All,

Has anyone in here ever done a repair on an Air 2000 PSU?

We have found that one of the transistors has blown and we are struggling to find a replacement.  All usual suppliers have been checked (RS / CPC / Farnell / Scattergood's), does anyone have any suggestions or is there a mod that can be done.  Its the 48v one (Im going from memory - its either 40 or 48) that has died.

Thanks
Ben

Ben P
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City Radio Services
City Radio Services
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Hi Ben.
If you still struggling with the Alice PSU, I have full schematics.
There are a number of 20mm fuses inside the PSU.
If the 48v Phantom Power has failed, disconnect from the mains and check the fuse (F4 350mA) feeding the bridge rectifier.
The semiconductors in circuit are bipolar diodes Q14/Q15 (ZTX753), TIP31 (easily available), CA3140 MOSFET, etc.

If it is the Phantom Power, check all mic leads as a short may have damaged the circuit in the first place. The Mic channels also have jumpers on the PCB to switch power to input A or B, or off the phantom power to dynamic vocal mics.
Anton Matthews
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City Radio Services - Thursday, June 02, 2016 11:09:10 AM
Hi Ben.
If you still struggling with the Alice PSU, I have full schematics.
There are a number of 20mm fuses inside the PSU.
If the 48v Phantom Power has failed, disconnect from the mains and check the fuse (F4 350mA) feeding the bridge rectifier.
The semiconductors in circuit are bipolar diodes Q14/Q15 (ZTX753), TIP31 (easily available), CA3140 MOSFET, etc.

If it is the Phantom Power, check all mic leads as a short may have damaged the circuit in the first place. The Mic channels also have jumpers on the PCB to switch power to input A or B, or off the phantom power to dynamic vocal mics.

Hi
Having found your forum entry wonder if you can help
Am trying to find the circuit diagram / service manual for our Broadcast truck 'Alice' which has an Alice 2000 desk www.10radio.com
There is what I suspect is a PSU fault and without a 'schematic' we are really stuck to troubleshoot the problem
Can you help or point me in the right direction please?

Cheers

 Anton

 10Radio Tech Team Director
 Mobile: 07889 074758
 Email: anton@10radio.org


David Boulton
David Boulton
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Hi Anton,

my advice is to sign up to the community radio group in Facebook. There is a sole trader who has purchased the rights for all the Alice gear that is left and they are currently offering refurbishment.

i cannot for the life of me remember the website, but i know it has been discussed on that Facebook group.




Regards

David Boulton
Brand Manager
Broadcast Radio Ltd
Anton Matthews
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David Boulton - Wednesday, July 04, 2018 3:49:24 PM
Hi Anton,

my advice is to sign up to the community radio group in Facebook. There is a sole trader who has purchased the rights for all the Alice gear that is left and they are currently offering refurbishment.

i cannot for the life of me remember the website, but i know it has been discussed on that Facebook group.



Many thanks for your advice - someone has come up trumps and we now have all the circuitry, so an inspection and repair will be underway soon...
Cheers
Anton Matthews
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To round things off...   Managed to get a set of circuit diagrams and effect a repair on our 'Alice's power supply.  Three 'puffed up' capacitors and the +\- 18volt rail voltage reguilators (of which I have a couple spare for grabs). http://www.10radio.com/wp/ Alice is (after and MOT) back on the road doing events and looking forward to the Taunton Flower Show - a splendid occassion https://tauntonfs.co.uk/ 
Thanks to all who helped   √
Best wishes,
Anton
10Radio Tech Team Director
 Mobile: 07889 074758
 Email: anton@10radio.org

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