MCUmall EPROM BIOS Chip Burner Forum
MCUmall EPROM BIOS Chip Burner Forum
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 True USB Willem Programmer (GQ-2X,3X,4X & GQ-4x4)
 GQ-4X reads from, but does not write to, M27Cxxx
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SparroHawc

USA
3 Posts

Posted - 03/22/2015 :  19:50:08  Show Profile  Reply with Quote
I purchased a GQ-4X with an accompanying ADP-054 adapter. I'm trying to burn two different kinds of EPROMs. One is the M27C160 and the other is the M27C322.

I seem to be able to read from the chips just fine. Admittedly I only have blank ones available to read from without potentially destroying some difficult-to-replace stuff, so I can't verify that.

When I attempt to write, it fails on the first address. I can read back the first address though, and when I read the failed burn, it appears as though the second most significant digit is incapable of writing a zero. If the second most significant digit of the first byte is a 1, it does attempt to write the second byte and will fail on that if it has a 0 for the second most significant digit.

e.g. I try to write
10100000

It fails, and when I read back from the chip, it reads
11100000

However, if the second digit is a 1, it moves on to the next byte.

I assume this is a hardware problem and not a software problem? It has the exact same issue with both chips mentioned.
Reply #1

ZLM

2945 Posts

Posted - 03/23/2015 :  12:44:02  Show Profile  Reply with Quote
How do you know the reading is correct.

There are many reasons can cause the write fail:

1. Poor chip pin contacting with adapter.
2. poor contacting between adapter and programmer.
3. Bad chip.
4. Wrong jumper settings on adapter.
5. Bad USB cable?
6. Bad adapter?
7. Bad programmer?
............

So, you may need to do more testing to get more information. V3/V5 jumper to see if it makes different.
Also, try

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Reply #2

SparroHawc

USA
3 Posts

Posted - 03/24/2015 :  00:17:40  Show Profile  Reply with Quote
I am using the correct jumper setting for the chip, and I have tried switching the V3/V4 jumper with no change (I usually leave it on V4 because I know these chips require relatively high voltage to write).

I have tried multiple chips and I have tried it multiple times, even shifting the chip and adapter a bit in the ZIF socket to make sure it has good contact.

The USB cable works fine; if it didn't, there is no way I would get as far as writing anything with a 1 for the second bit.

It may be that my adapter or burner are bad. I purchased the two as a set recently; is there a manufacturer warranty? Can I send them in for a replacement?
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Reply #3

ZLM

2945 Posts

Posted - 03/24/2015 :  16:44:37  Show Profile  Reply with Quote
All programmers have warranty. Contact support@mcumall.com for the warranty. It is best if you can send back the programmer with your chip together, so that they can verify the problem, and send test the now programmer before send them to you.
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Reply #4

SparroHawc

USA
3 Posts

Posted - 03/24/2015 :  20:35:17  Show Profile  Reply with Quote
Will do - thanks for your help, ZLM.
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