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DSP-610 Photos
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Author:  N4BKT [ Fri Sep 21, 2012 5:18 pm ]
Post subject:  Re: DSP-610 Photos

How my build is going using the board as published. If I had to do it again I would wait til T3 was mounted before installing C143- it made the soldering tight. I installed a heat sink on VRG1 as it makes it harder to accidentally knock it about- and I had an extra anyway... anybody spot obvious errors?

Attachments:
File comment: The Coto relays with the ECO per Jim - caps added across diodes on top of board.
IMG_20120921_173047-1024x768.jpg
IMG_20120921_173047-1024x768.jpg [ 192.42 KiB | Viewed 6310 times ]
File comment: The LM317 needs an insulator
IMG_20120921_173000-1024x768.jpg
IMG_20120921_173000-1024x768.jpg [ 194.98 KiB | Viewed 6310 times ]
File comment: Heat Sink on Finals
IMG_20120921_172945-1024x768.jpg
IMG_20120921_172945-1024x768.jpg [ 172.58 KiB | Viewed 6310 times ]

Author:  jimveatch [ Fri Sep 21, 2012 9:21 pm ]
Post subject:  Re: DSP-610 Photos

Nice looking board.

The RD16HHF1's don't need insulators and the heat transfer is better without them. You'll need to couple that heatsink to something else because it doesn't look like 70 to 100 sq. in. maybe you can force air over it.

Jim.

Author:  N4BKT [ Sat Sep 22, 2012 12:19 pm ]
Post subject:  Re: DSP-610 Photos

Hey Jim,

It's about 35 in square and I do have a fan to suck air past and out the back panel. I will remove the insulators as you suggest. As it is the heat sink floats- and I am concerned removing the insulators may create a ground loop and a loss of stability as mentioned by G6ALU in his similar design notes here: http://www.radio-kits.co.uk/radio-relat ... /index.htm

May I ask how the calculation result of ~70 sq inches is arrived and at what duty cycle is it targeted?

73 es HAGWE

Bill
N4BKT

Author:  jimveatch [ Sat Sep 22, 2012 8:07 pm ]
Post subject:  Re: DSP-610 Photos

I have always grounded the tabs of the RD16HHF1's to the heasink that was electricall connected to ground (not just by the transistors) given the RF issues that you are going to face by having the 25W amplifier on the board with the low-level circuits, you are going to need all the ground you can get. The PCB uses a 2 oz copper ground plane but it still has RFI issues.

Jim.

Author:  thiruppathy [ Tue Oct 30, 2012 4:54 am ]
Post subject:  Digital Graffiti Wall

wow,, Great Post.

Author:  nicorar [ Tue Jan 01, 2013 2:41 am ]
Post subject:  Digital Graffiti UK

Wonderful 610 photos! interesting.

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