is that your scope?  or is it a side effect of work?   I bought an old 2216
analog Tek scope and that's ok, and I also have a USB module for my lab PC
that is a multi function scope and signal generator.  I also have a small
USB powered logic analyzer.



On Sat, Mar 28, 2015 at 12:49 PM, Stephen Adolph <[email protected]>
wrote:

> WAIT - that is a storage scope!  You should be able to really dig in
> here.  But you will need to start looking at single traces and get clever
> on triggers...
>
>
> On Fri, Mar 27, 2015 at 8:14 PM, Jovan Trujillo <[email protected]
> > wrote:
>
>> Hi Guys,
>>
>> I'm trying to fix a dead Model 100 which gives a blank screen when
>> powered on. The machine is not responsive to keyboard input as well. I
>> can't get it to beep. While poking around with the oscilloscope it
>> seems the power is ok. The clock input to the CPU is also probably
>> good enough. The only chip that gives me a messy signal is the 81C55,
>> which routes all of the I/O from the keyboard and LCD screen. I've
>> tried reflowing all the connections to the chip. There was a moment
>> when the thing beeped as I pressed a bunch of keys and the screen was
>> giving me garbled output, but upon hitting the reset button everything
>> died again.
>>
>> I'm thinking I need to replace the 81C55 but wanted a second opinion.
>> What do you guys suggest is a good replacement if I do need to buy
>> one?
>>
>> Here is a lonk to my oscilloscope output:
>> http://jovan.freeshell.org/weblog/
>>
>> Thanks,
>> Jovan
>>
>
>

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