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Sansui 9090 F-2436 board.

J

jazzbum

New Member
I'm drawing up a PCB to replace an F-2436 board in a 9090 I salvaged from the dump. It works fine as a pre-amp so there's hope for it , but there's no driver board so I need to make one . I have a couple of queries , the first being a request for a sketch or dimensions of the board , so I can get the shape and placement of the two tags that sit up from the top , and also if possible , the shape and dimensions of the bracket the tags fit into since that is missing too. Any help much appreciated.
The second query is : why do many of the boards I've seen photos of , pre and post - restoration , only have one large resistor visible on one channel , the R51 / R52 10ohm 3W ones , I presume the other is behind the board but why ? There is the same amount of room on each side of the PCB it seems to me , I'm puzzled.
 
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jazzbum said:
I'm drawing up a PCB to replace an F-2436 board in a 9090 I salvaged from the dump. It works fine as a pre-amp so there's hope for it , but there's no driver board so I need to make one . I have a couple of queries , the first being a request for a sketch or dimensions of the board , so I can get the shape and placement of the two tags that sit up from the top , and also if possible , the shape and dimensions of the bracket the tags fit into since that is missing too. Any help much appreciated.
The second query is : why do many of the boards I've seen photos of , pre and post - restoration , only have one large resistor visible on one channel , the R51 / R52 10ohm 3W ones , I presume the other is behind the board but why ? There is the same amount of room on each side of the PCB it seems to me , I'm puzzled.
Click to expand...
Just search F-2436 on eBay. Very good repo from AudioKarma members.
 
Hi , thanks for replies but in UK eBay only offers one bare board which is £36 imported from USA , and I'm quite enjoying designing my own board as a replica of the original.
 
Thanks Hippocrates . One more question - I've designed the board with one change which I now think is wrong, and that is to include a separate heatsink for a replacement for the 2sc984 . I have read suggestions on the lines of BD137 or KSC2383 and figured they could go on a separate heatsink but now I realise that the reason it's fastened to the same heatsink as the driver transistor is so that it follows the same thermal changes and alters the bias accordingly. Is this correct and does it actually work for plastic transistors , or am I better off shelling out for 2sc984 ? I suppose I also worry that very old stock 2sc984 or cheap reproductions might not be as good .
 
jazzbum said:
I have read suggestions on the lines of BD137 or KSC2383
Click to expand...
I like the TO-126 better for that application, on the 9090 and 8080 I've used BD139.
Attached you will find the contour of the board with some measurements.
I don't remember the model of the edge connector for that board I will have to look for it.
On F-2436 the pads of the edge connector are like this.

This will get you starting, have fun with it.

1736361438410.png
 

Attachments

THanks , the drawing is just what I need. I'll look at the BD139 - does it have to be thermally attached to TR13 / TR14 or can it stand on its own heatsink?
 
Thanks for all your help Hippocrates , I'll press on. I'm not sure if all sockets are the same , mine measures 68mm across all 18 pins , which gives me 4mm betweens centres. I'll get the board made and then no doubt be back on here.
 
jazzbum said:
Hi , thanks for replies but in UK eBay only offers one bare board which is £36 imported from USA , and I'm quite enjoying designing my own board as a replica of the original.
Click to expand...
A PCB house is going to charge that in shipping costs anyways, no?
 
No , I am doing the layout in Easy EDA and sending it to their production place , JLC I think.. I've had their boards before , they're solid enough and it works out at less than £15 for five boards. This is a rough MK1 version , not the right dimensions.Screen Shot 2025-01-11 at 17.37.54.png
 
jazzbum said:
No , I am doing the layout in Easy EDA and sending it to their production place , JLC I think.. I've had their boards before , they're solid enough and it works out at less than £15 for five boards. This is a rough MK1 version , not the right dimensions.View attachment 3396609
Click to expand...
print it on paper first if you need it, no reason to order things with wrong dimensions
 
Hi , i gave the wrong impression , that was just a gerber file I uploaded to the manufacturers website to get an estimation of the price . I thought that perhaps a shaped board would push the price up , but not so. The board that gets made will have the original setup for the 2sc984 and be the right dimensions.
 
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