[sdiy] broken oberheim matrix 6r

[Bob Weigel]

Yeah sometimes that is the best way.  If you are in a real hurry  and a 
board is hard to get out...hehe..you might take sharp nips and cut the 
pins leaving most of it sticking up.  Toss the old chip then flux the 
new ones and pretin.  Flux again then melt each onto the pins quickly.  
If it has to be done..in 10 minutes :)

I haven't personally seen the chips fail.  But always a possibility.  
Often several of them are used in some kind of scheme since they have 
limited outputs.  So get the diagram for one and start testing to see if 
all the outputs are doing something reasonable.  There could also be two 
cpu's in those I can't recall.  In the kawai of similar design (SX240) a 
power supply issue took out the cpu, and an old ssm narrow package 6116 
memory chip and possibly another that I replaced before I got there.  
What a pain that was. But that would allow all the patches to be 
editable etc. but no sounds of course since that cpu system handled the 
oscillators -Bob

David Brown wrote:

> I had an 8253 fail in my Matrix-1000 which is basically the same 
> circuit design.  Two data pins shorted together with ~100 ohms.  
> Totally screwed up the processor.  I had to shotgun cutting data lines 
> to figure out where the short was.  The good news is that the 8253 is 
> cheap and available but a bear to replace.  I ended up cutting off all 
> the pins and removing each pin individually with a solder sucker.
>
> Dave
>
> At 12:46 PM 4/4/2007, Danjel van Tijn wrote:
>
>> Hi karl,
>>
>> Does the 8253 timer commonly fail? I will definitely check it out...
>>
>> thanks for the tip!
>>
>> Danjel
>>
>> On 4/4/07, karl dalen <dalenkarl at yahoo.se> wrote:
>>
>>> Have you checked the 8253 timer?
>>>
>>> If these dont work you wont get any sound!
>>>
>>> KD
>>
>
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