Hello again everyone. I have been hunting down several different IC's for a couple of Apple II cards. Specifically a Z-80 Microsoft Softcard clone and a Mountain Hardware, Inc. Apple Clock. Got the chips no sweat but the Mountain Card is missing the crystal. I found a nice closeup of the same version of the card but I know diddly squat about how to identify (and subsequently search for) these things. i never even knew what those little cans/canisters were when I was originally using this stuff, I just knew when something did or did not work!
THIS LINK HERE will show the front of the card and the component I am missing is the bottom left corner (silver crystal canister/crystal)
I have been learning a lot from this site and trying things out. When/if I get the replacement part the next step will be to attach it! Clock card works but does not keep accurate time due to the missing component.
Can anyone help me see if a place like Digikey or Jameco has a viable replacement? Again, not sure what I am looking at so hard to know what to search for. Thank you for your help.
Clock card was also missing the 74LS04N chip but that was easy to identify/find!
Thanks again,
Zan
Hello,
To me, it's a 1 Mhz crystal.
You can find it on eBay.
Hello Zan,
the crystal is deffinitly a 1,0000 MHz type.
2 remarks:
the CD4077 and the CD4013 in the left part of the middle row have changes of top surface ....
this occasionaly happens if the ICs have got too hot or have exceeded limits in powersupply....
my advice would be to replace them.....
the second remark is related to the time itself:
the trimming capacitor at the upper most left corner - ( or right top besides the marking:SN of the serialnumber )
is determined to adjust the clockcycle and determines the speed of the clock ! It permits you to adjust the
precision of the clock ( getting it run few tenthparts of seconds faster or slower ).
last comment:
when the computer is shut off the clock stops working unless you add a 9 Volt backup source at the 9V plug in the lower row ( 9 Volt block battery )- beware of the polarity of the jack to plug in there....
if you are not sure use an open plug and measure the GND line to find out where minus of the battery must be connected to... the battery was formerly fixed to the card with the stripcable..... the GND line is connected to pad 26 at the rearside of pad 25 at the slot - it must be connected to the GND / Minuspol of the battery.
speedyG
Speedy and all, thanks for the comments.
Speedy, that photo is from the apple2.org.za archives that showed the crystal missing from my clock. That is why I was not sure what I needed since that was the only photo I found and the other Mountain clock card I have is different from the one in the photo and the one I have missing the crystal.(virtually identical but newer with some different style components(but same numbers) and with the one card missing parts I did not want to assume they were the same as the other card) The clock card in question has the battery still attached and the clock does show up in the Mountain software when booted and I can switch it to allow the changing of the time. The crystal on my clock is gone and you can see where it was soldered to the board (old solder still there and empty holes) My card does not have the discolored chips like the one in the photo from the archives, so I should be good just replacing the missing components. I have ordered a replacement crystal (as well as the chip I mentioned that was missing....when replaced with one from another mountain clock the card worked) so once I get the parts I will let everyone know how I made out.
Thanks again,
Tony
Respectfully. I disagree with having to replace the CD4077 and the CD4013. While overheating can cause changes in surface finish - I don't believe that to be the case here. The pattern is all wrong.
I have many IC's which exhibit this sort of change. Mfg. techniques and printing and surface finishing were not as consistent back then as they are now. This is a simple matter of age and handling.
Hello Keatah,
it was not a MUST but rather more a MAY BE A GOOD IDEA recommendation.
I said: this occasionaly happens ... not allways....
and ZAN mentioned the clock to be failing in precision....
the reason may be a twist of the trimming capacitor, but it might also have cause by damaged chip.....
in such case all possible suspects should be listed not only those in first place of the list....
BUT of course you are right.... exceeding power or heat must not be the reason of the changes in surface - but it can be...
speedyG
It is strange that a 1Mhz crystal would be used in any modern clock in order to keep the time. This chart will tell you what that crystal is probably for:
http://en.wikipedia.org/wiki/Crystal_oscillator_frequencies