Re: 128DCR lockups

Hi Dan,

Hmmm never gave much thought to that :)

Thank you,

Terry Raymond

On Thursday, September 17, 2015, Daniel V. Mackey <n2dvm@arrl.net> wrote:

> At 06:17 PM 9/17/2015, you wrote:
>
>> Hi all,
>>
>> I proudly own 3 128DCR's just last year I attached my V2 Super CPU MMU
>> adapter and its jumper clips clip to certain pins on the 8502 CPU of course
>> using the CMD installation guide.
>>
>> This all seemed to work okay I had the computer on for a few hours and
>> then out of the blueÂ
>> some random fine dots appeared on the screen and it locked up completely.
>> This was intermittent so I never knew when computer would lockup. Â
>>
>> I asked Ray Carlsen about this he suggested isolating each chip with a
>> piece of thick cardboard heat each chip this way and maybe the lockup might
>> happen.
>>
>> I heated the MMU chip BAM it locked up the same way.
>>
>> I removed the MMU chip out of the MMU adapter, installed MMU chip in MB
>> socket heatedÂ
>> again, Bam same lockup.
>>
>> I robbed an MMU chip out of a dead Flat 128 installed in socket heated it
>> but finally no lockup this time.  I wonder if the Super CPU MMU adapter if
>> that is installed wrong if this might damage the MMU chip.  I had always
>> installed mine correctly anyway and recheckedÂ
>> a few more times before applying any power.
>>
>> I just wanted to pass this info on maybe some know of isolating chips in
>> this way
>> this sure made my day to figure this problem out. Â
>>
>> Im just wondering if anybody else has had the same MMU problem or bad
>> MMU,Â
>> intermittent lockups?
>>
>> I like the V2 SCPU for the 128 but it seems to be a bugger to get it to
>> run correctly I have always had problems occur with the MMU adapter itself,
>> the Super CPU unit has alwaysÂ
>> performed good.
>>
>> Positive SUPER CPU comments only I really like the unit, but really
>> concerned about the MMU design.  The MMU I believe has something to do
>> with the timing on the MMU so theÂ
>> Super CPU can run in 128 mode I may have missed other details.
>>
>> Terry Raymond
>>
>
>
> I soldered the wires from the MMU board directly to the CPU, I had no more
> problems. Those clips suck!
>
>
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>
> QUOTE : "A Clean bench is a sign of a weak mind."
>
>
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