CD player mods-newbie

[quan]

Hi guys, 1st post-need help!!!!
I have a Thule spirit cd player- to be mod. How do i replace the rectifier bridge-W1G-100V,1.5amp rating with HexFREDs(TO220)?
How do i build a rectifier bridge from those TO220 HexFRED?.Thanks in advance.

[JonHarrison]

Hi,

In the picture below you can see the pinout of the bridge module and also how it is connected internally. You need to wire the individual diodes in the same manner. The simplest option may be to put them on a small piece of veroboard and then solder short wires down to the pcb.

Cheers,

Jon

[quan]

Hi Jon, basic questions here-so i wire the hexfred in series/parallel on vero board then short wires to the original holes yeah? Would these short wires degrade performance?

[JonHarrison]

Hi,

Yes connect the diodes as two serial pairs parallelled and connect the AC to the inner and the +/- to the outer as shown in the diagram. If you want to snub the diodes you can fit the capacitors (and resistors if required) on the vero board too.

Do you have a schematic for the CD player. Is this bridge part of a linear or SMPS ? A photo of the board layout would also be helpful.

The wires will have some effect but twist them together and keep them as short as possible and you should be ok. If you are worried you may want to think about moving the bulk capacitor, transformer connections and perhaps the input filtering to the vero board - depending on board layout and power supply design. The input filtering capacitors if fitted should be as close to the rear of the power socket as possible to be effective. A small series resistance (the connecting wires) after the bulk capacitor can actually help.

I have replaced one of these bridges using axial diodes on the original board but it wasn't pretty - you have to cross diodes over one another and stack them on top of each other. You can figure it out if you look at the wiring of the bridge module and compare it with the discrete diode layout.

Have you thought about using Schottky diodes instead ?

Cheers,

Jon

[quan]

Hi Jon, trying to find the camera-need fixing thus unable to provide a layout of cd board-i don't have a schema for the cd player.
i think moving the transformer/capacitor onto the veroboard would be too much for a newbie like me.
The bridge rectifiers(4)is supplying for all the analogue n digital boards-?linear?SMPS.
you mentioned Schotky diode-what would be a suitable alternative?
PS- i am still waiting for 25 HexFREDs from RS components!!!!
quan.

[JonHarrison]

you mentioned Schotky diode-what would be a suitable alternative?

11DQ10 is a common choice although this is rated at a lower current than your bridge. There are a number of surface mount options also. I personally like the SiC (silicon carbide) diodes but these are very expensive !

I really need to see a photo of the psu before going any further.

[tubenut]

I normally fit 2 diodes on to the PCB where the bridge was (with long leads so they stand proud. I then sollder the remaining 2 diodes with leads clipped short (but hooked around the other diode leads) on to the leads of the PCB mounted diodes. In CDP and Pres the current draw is typically low enough for this to be just fine.

Another neater way I use as well is to mount 2 diodes on top of the PCB through the holes and the remaining 2 below the pcb just soldered on to the pads. You need a fair bit of clearance between PCB and chassis for this method though.

[JonHarrison]

tubenut,

I've done something similar with axial diodes but how easy is this to do with four TO220 packages ?

Regards,

Jon

[tubenut]

how easy is this to do with four TO220 packages ?

Not.... Nearly impossible. I tend to use Axial where I can. I use NOS BYT53 and BYT56 mostly. Tried some Schotky diodes a decade ago and preferred the BYTs...

I have "threatened" in my mind to make a kind of small universal PCP for years but never got there. I thought of a Diagonal cross of tracks (though not crossed) on a small 2,5 cm * 2,5 cm PCB with multiple holes drilled along each track. Extra holes would allow caps as well I suppose and most size diodes and leadd outs for replacing most scuare lay out bridges. Those in line jobs may need another PCB or insulated fly leads...

[quan]

Hi guys, trying to fix the camera for a picture-like they say-worth a thousand words!!!!
i am still not sure what to do-
tubenut-do you have a picture of what you do to replace the bridge rectifier?
i have received the Hexfred TO220 yesterday-can't wait to get my hand to it.
Jon-here comes the picture.