MCUmall EPROM BIOS Chip Burner Forum
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 Using The Enhanced/Dual power Willem Programmer
 Dual power willem Vpp questions
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lbaeza

7 Posts

Posted - 06/13/2009 :  08:37:41  Show Profile  Reply with Quote
Hi

I bought a Dual power Willem eprom programmer from Mcumall several years ago, mainly for burning 2716/2732 eproms with no problem at all.
Last week I wanted to burn a 27C512, so I set up the right Vpp and Vcc, but couldn't burn the eprom. After several tries, I started to check if everything was OK on the burner side. So I checked Vpp and values were off range. Then I went to my computer BIOS and set up the EPP printer port mode, but I had Vpp values off range too. So I started checking all possible combinations of Vpp and Printer port mode, and the results are in the attached picture (DMM = Values I got with my digital multimeter when checking Vpp values).

Image Insert:

50.44 KB

Is there a problem with my EPROM programmer? What components should be replaced when I get these values for Vpp? Should I give it a try using another computer?

Regards

Edited by - lbaeza on 06/13/2009 08:39:51
Reply #1

ZLM

2926 Posts

Posted - 06/13/2009 :  23:34:53  Show Profile  Reply with Quote
The printer port mode shoulde not change the VPP value. It seems the programmer Vpp circuit has some problem.

Check the schematic:
http://www.mcumall.com/forum/topic.asp?TOPIC_ID=2028
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Reply #2

lbaeza

7 Posts

Posted - 06/19/2009 :  17:51:47  Show Profile  Reply with Quote
Hi

Thanks for your reply, ZLM.
I have downloaded the schematics, but I am not very clear where to look at...
any ideas what components in particular I must check?

Regards
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Reply #3

ZLM

2926 Posts

Posted - 06/21/2009 :  06:43:44  Show Profile  Reply with Quote
Check U11, MC34063A output. See if it has a correct VPP voltage.
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