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Rabite2
9 Posts |
 Posted - 03/06/2018 : 10:58:11
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Hey! 
I just got my pcb5.0 willem eprom programmer (the only one I could afford), the one with the dipSwitches.
I got it all set to program some 27c801 eproms for an snes repro, only to find out it wouldn't even get a bit right after programming. Classic error 0x000000 chip = 0x04 buffer = 0x20
After a few research I see that this is a very common problem with this programmer and that you should set the right jumpers before you burn it.
I set the jumpers as adviced by the information:
1) Remove the jumper from the 3-way jumper (J3) and place it between pins 6 and 7 on the 8-way one (A19 and P1)
2) Anything else set to normal
3) DIPswithces set as adviced
4) Use a 12VDC 1Amp PSU
5) Set anything else to normal (12,7V Vpp and Jumper 1 Jumper2 set to normal)
Still I got no luck
After further research to the board itself (via test h/w from the software) I found out that the pin 26 (Address 9) of the zif has only 3.3V high voltage, when every other address returns 5V. In addition, I cannot set the Vcc. No matter where I place jumper 8 I always get solid 5.03V Vcc.
Here is an HD photos of my setup (I can provide more, if needed):
Download Attachment: 
4069418
Any help is appreciated, please.
Thanks in advance. |
Edited by - Rabite2 on 03/06/2018 11:02:42
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| Reply #1
Rabite2
9 Posts |
Posted - 03/10/2018 : 08:26:54
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| Need help |
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| Reply #2
anniel
2540 Posts |
Posted - 03/11/2018 : 04:52:10
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quote:
Originally posted by Rabite2
Need help
Your picture does not work. |
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| Reply #3
Rabite2
9 Posts |
Posted - 03/11/2018 : 11:49:29
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I will update it asap.
By the way, is the A9 address supposed to have such a low voltage? I am curious, because in the 27c801 diagram is stated that this is a special pin and it could take up to 13V, as opposed to all the other addresses that do not surrpass 7V. |
Edited by - Rabite2 on 03/11/2018 11:50:26 |
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| Reply #4
anniel
2540 Posts |
Posted - 03/12/2018 : 04:38:01
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quote:
Originally posted by Rabite2
I will update it asap.
By the way, is the A9 address supposed to have such a low voltage? I am curious, because in the 27c801 diagram is stated that this is a special pin and it could take up to 13V, as opposed to all the other addresses that do not surrpass 7V.
Just to be clear you are using an UV or OTP?
A9 is no special pin on a 27C801, it's only to get the chip ID... |
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| Reply #5
Rabite2
9 Posts |
Posted - 03/12/2018 : 05:06:39
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Well, it seems I am not able to upload the images via the attach function here, so I'll upload them to imgur and share the link.
To start things up, this is my board:
https://imgur.com/a/LtCaA
I can mark the chips and jumpers if you need so, cause I know the image quality is a little... blurry 
Anytime I try to program a 27c801 (M27c801, to be exact, the "ST Electronics" ones) I get the following classic error:
https://imgur.com/a/LSirJ
In the EPROM datasheet is stated that 6.2V +-0.25V at Vcc are needed for the ic to be programmed but I could not set the Vcc voltage no matter how I placed Jumper 8.
After a little research I found the schematic of the pcb4.5 revision: http://msevm.com/md/766/sch3m.gif,
which seems to be very similar to mine, with the exception of the plcc ports and some more (troublemaking! ).
https://imgur.com/a/F9S1n
Those two aren't stated anywhere in the schematic. Also, on the board, above J12 is written "15 open 3.6V" and I found out that the Vcc pin (pin 32) of the zif is connected to the top left pin of the jumper. If I remove the top jumper, the power led becomes noticeably brighter and then I am finaly able to set the Vcc from Jumper 8, following the information of the jumper schematic! http://www.mcumall.com/support/StandardWillemUserGuide_files%5CPCB5.0JumpersLayout.jpg
I haven't noticed any voltage difference if I remove jumper 16 (which is mentioned as "spare jumper" in the last schematic), but I am not sure how it works. Will it cause any change whether it is placed or removed? [P.S. The Vcc pin of the zif is connected to the left pin of the jumper.]
I still haven't found the reason why I get only 3V at A9 (I also get only 4V at A19), but i found out the following:
1) The A9 signal passes through a diode before reaching the zif and this diode gives me 606 Ohm resistance, so maybe that's the reason of the problem (note that I checked this with my multimeter set to resistance and I paid attention to the polarity)
2) The A19 signal starts from pin 2 of a 4015 chip and is also connected to pin 7 of the same one before leaving for the zif, so again maybe that's why I get 4V from the zif.
P.S. I know this post is enormous, but I've got two more things (please? ):
1) Does anyone know what do those jumpers do?
https://imgur.com/a/wme0I
2) For some reason the ground of the board is not 0V, but ca. 0.6V. Is that a problem?
That's it; hope this does it 
Thanks in advance! |
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| Reply #6
Rabite2
9 Posts |
Posted - 03/12/2018 : 05:13:33
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quote:
Originally posted by anniel
Just to be clear you are using an UV or OTP?
A9 is no special pin on a 27C801, it's only to get the chip ID...
Sorry, I didn't notice your post; I am using the UV ones and I have checked them to be blank. |
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| Reply #7
anniel
2540 Posts |
Posted - 03/12/2018 : 07:12:45
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quote:
Originally posted by Rabite2
Well, it seems I am not able to upload the images via the attach function here, so I'll upload them to imgur and share the link.
To start things up, this is my board:
https://imgur.com/a/LtCaA
I can mark the chips and jumpers if you need so, cause I know the image quality is a little... blurry
Anytime I try to program a 27c801 (M27c801, to be exact, the "ST Electronics" ones) I get the following classic error:
https://imgur.com/a/LSirJ
In the EPROM datasheet is stated that 6.2V +-0.25V at Vcc are needed for the ic to be programmed but I could not set the Vcc voltage no matter how I placed Jumper 8.
After a little research I found the schematic of the pcb4.5 revision: http://msevm.com/md/766/sch3m.gif,
which seems to be very similar to mine, with the exception of the plcc ports and some more (troublemaking!).
https://imgur.com/a/F9S1n
Those two aren't stated anywhere in the schematic. Also, on the board, above J12 is written "15 open 3.6V" and I found out that the Vcc pin (pin 32) of the zif is connected to the top left pin of the jumper. If I remove the top jumper, the power led becomes noticeably brighter and then I am finaly able to set the Vcc from Jumper 8, following the information of the jumper schematic! http://www.mcumall.com/support/StandardWillemUserGuide_files%5CPCB5.0JumpersLayout.jpg
I haven't noticed any voltage difference if I remove jumper 16 (which is mentioned as "spare jumper" in the last schematic), but I am not sure how it works. Will it cause any change whether it is placed or removed? [P.S. The Vcc pin of the zif is connected to the left pin of the jumper.]
I still haven't found the reason why I get only 3V at A9 (I also get only 4V at A19), but i found out the following:
1) The A9 signal passes through a diode before reaching the zif and this diode gives me 606 Ohm resistance, so maybe that's the reason of the problem (note that I checked this with my multimeter set to resistance and I paid attention to the polarity)
2) The A19 signal starts from pin 2 of a 4015 chip and is also connected to pin 7 of the same one before leaving for the zif, so again maybe that's why I get 4V from the zif.
P.S. I know this post is enormous, but I've got two more things (please?):
1) Does anyone know what do those jumpers do?
https://imgur.com/a/wme0I
2) For some reason the ground of the board is not 0V, but ca. 0.6V. Is that a problem?
That's it; hope this does it
Thanks in advance!
A diode does introduce a voltage drop...
The ground should be your reference point for all your voltage measurements... |
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| Reply #8
anniel
2540 Posts |
Posted - 03/12/2018 : 07:13:58
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quote:
Originally posted by Rabite2
quote:
Originally posted by anniel
Just to be clear you are using an UV or OTP?
A9 is no special pin on a 27C801, it's only to get the chip ID...
Sorry, I didn't notice your post; I am using the UV ones and I have checked them to be blank.
Ok that's what I was looking for. |
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| Reply #9
Rabite2
9 Posts |
Posted - 07/14/2018 : 01:04:21
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Just to close this topic, I found the source of the problem and it is so that windows keep polling the parallel port where you have placed the programmer and you need to prevent them from doing this.
Someone has posted a registry key for xp that solved this and I think it should work on 7, too
Just follow that link "shrubbery.net/~heas/willem/Program_EPROM/XP_stop_polling.reg" (just select all the text, without the quotes, and click "open as URL") and by right-clicking anywhere on the page select "save page as..." and save it as "all files (*.*)". Then just open the file you downloaded and click yes to the prompt
Hope that helps anyone that still uses that kind of old equipment as I do |
Edited by - Rabite2 on 07/14/2018 02:20:20 |
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Unable program 27c801 and set Vcc
