[sdiy] on the search for some MXR Digital Delay memory chips

[Todd Sines]

Thanks to Paul Perry for the tip-off,  it seems like some Arcade Game  
suppliers have these chips. So I'm going to try and round them up  
soon.  :)


+odd
--
On Sep 19, 2008, at 10:39 AM, ChristianH wrote:

> On Fri, 19 Sep 2008 09:21:36 -0400 Todd Sines <sines_tr at scale.gs>  
> wrote:
>
>> I have 2 dead MXR blue face Digital Delay units that look like this:
>> http://www.sonicflux.com/pics/mxr_ptx_dd1_c2.jpg
>> [the one on the bottom]
>>
>> Takeshi, the tech that has been repairing them, cannot find the
>> memory ICs.
>> he gave me this list of possible ICs that might work.
>>
>> "This is Memory IC of MXR.
>> long time ago. 4 or 5 company made this memory IC.
>> AM9060.
>> D2107C
>> uPD411
>> MM5280
>> TMS4060.
>> Sorry I do not know name of company.
>> so you can use any those type IC for MXR Digital Delay.
>
> Gee, haven't seen those numbers in a long time...
> Looks like AMD (?), Intel, NEC, National (?) and Texas Instruments, in
> that order.
>
> Was a faily standard dynamic RAM chip in the late 70s. I should have
> data sheets from Intel and NEC at home. IIRC, it's 4kBit. Wow, that's
> 4096 whole bits in one chip... <gr>
>
> Maybe it's sufficiently similar to later dynamic RAMs, like the 4164,
> which I have seen quite recently at my supplier. Quite often later  
> chips
> just have additional address inputs, due to the increased capacity.
> Might work to simply ground those inputs, and use only the needed part
> of the larger capacity.
>
>> I imagine I'll need somewhere between 30-80 of these things. I got a
>> ridiculous quote  for $580 for 100.
>>
>> Anyone have a batch of the chips above that won't be more than $200
>> total?
>
> Unless there has been a misbehaving power supply unit, I wouldn't  
> expect
> *lots* of memory chips dead.
>
> If really all of the memory is shot it might be a worth considering
> to redesign the circuit using current static RAM chips (may even be
> possible to replace the whole bunch with a single chip). If you have a
> schematic, that is.
> Most certainly not for the faint of heart, but this is diy ;-)
>
> Christian
>
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