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Post by jukenorman on Feb 3, 2021 9:57:36 GMT
Hi Roger,
Good news! One bit of clarification - did the jukebox ever work with the MC14503 installed? Actually I can see "new to me" in your signature so obviously not while you've had it! And probably didn't ever work!
Norman.
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Post by rogerroll on Feb 3, 2021 21:01:01 GMT
Actually, it did work for a few months with the MC14503 on the Logic Board. From my gleaning of the descriptions on the internet, it has the same functions/parameters as the original. Should I be worried that this new chip won’t last?
Btw, I also installed a little digital voltage display to keep tabs on the 9.6v.
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Post by jukenorman on Feb 4, 2021 11:16:30 GMT
The Rock-Ola parts list calls for MM80C97N which is from the CMOS logic family. The MM14503 is from the TTL logic family (I have just downloaded the data sheets to have a look!) which is why the chips are the same description but the numbers so different. Best sticking to the MM80C97N and if that's what you got, there would be no reason why it wouldn't last.
Norman.
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Post by Ron Rich on Feb 4, 2021 13:28:14 GMT
Hi All,
Can anyone 'splain me what the difference between TTL and C-MOS is-- I have heard that C-MOSS is "better"-- but have also heard it is much more sensitive to static charges, when un-installed ? Thanks, Ron Rich
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Post by rogerroll on Feb 4, 2021 14:51:36 GMT
The replacement chip I found is from Fairchild, P0330AB, CD4503BCN. A description I found includes this: <<Pin-for-pin replacement for MM80C97 and MC14503 3.0 VDC to 18 VDC>> I will nonetheless order some actual MM80C97N (they have a longer delivery wait time, which is why I went for the others). Thanks again! |
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Post by jukenorman on Feb 4, 2021 17:12:36 GMT
Ron,
In the simplest of terms, the difference between TTL and CMOS is progress; CMOS is a generation on from TTL and could be described as allowing more sophistication of circuits. In Roger's case he had two chips which were like for like replacements (one CMOS, one TTL) and in basic circuits they can be mixed. In more complex circuits there can be interfacing problems because although they operate in the same voltage range, current requirements are different.
Roger,
I haven't checked that Fairchild chip but the CD4503BCN ident would suggest that it is the same as MC14503 and it is correct to say that it is a pin for pin replacement for the CMOS chip. The fact that the original MM80C97N was replaced by an MC14503 which has subsequently failed might suggest that it's not the ideal long term replacement. The MM80C97N isn't particularly expensive so getting one might be sensible.
Norman.
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Post by Ron Rich on Feb 4, 2021 17:47:52 GMT
Hi Norman,
Thanks-- that's basically what I remembered, except that I have heard people who should know, say that there really was no difference between the two, other then operating voltages--sometimes-- ? Then you get into the prefix and suffix differences--- way above my pay grade ! Ron Rich
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