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 Using The Enhanced/Dual power Willem Programmer
 5.0E A12 and A15 lines low voltage under test
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freddyisaac

USA
2 Posts

Posted - 06/18/2015 :  14:23:58  Show Profile  Reply with Quote
Hi,

Not having much luck using my 5.0E. Using parallel port an dlatest version of the software. Also using an external 12v power suply. Getting good Vpp and Vcc.

Tested the ZIF using the test page and I only get 1.8V on both the A12 and A15 lines. Funny though they both go to "high" together. All other lines go 5v "high" correctly.

With power of the A12 and A15 pins have 132 Ohms across them - doesn't sound right. Thought it might be the 4015 shifters so I replaced two of the the ones shown in the schematic for 3.0 version and those that test as connected with new ones but no change.

In fact I get 132 ohms with the 4015s removed. Not sure what else is connected to these pins on a 5.0E.

Any help would be much appreciated.

Cheers

Reply #1

freddyisaac

USA
2 Posts

Posted - 06/23/2015 :  14:42:56  Show Profile  Reply with Quote
update

After replacing the 4015 chips with no change, I decided to replace the ZIF itself.
Anyways after replacing this the problem has been rectified. No more resistance between A12 and A15. Might have been a very small solder splash or some other foreign conductive matter.

I am now able to program my 27C801 - YAY !!

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