Problem reading/writing EPROM

aha2940

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That's what I'm thinking. I had you write AAAA because it should bypass the bad bit.

Try writing 5555 on a blank eprom if it's a bad bit I think it will read 5515

You were absolutely right. After writing a buffer of only 55 to an EPROM, I got the EPROM filled with 5515. Now the problem is I don't know if the programmer is not writing the files right, or is simply reading them wrong...any way to know?
 

bustedstr8

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It's definitely not reading that bit correctly, you wouldn't fail to verify every blank you had.

Only way I can think of to verify that you are still writing the proper data is to use another programmer or find someone to read a 5555 filled chip.

If you can't find anyone close I have no problem doing it.
 

aha2940

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It's definitely not reading that bit correctly, you wouldn't fail to verify every blank you had.

Only way I can think of to verify that you are still writing the proper data is to use another programmer or find someone to read a 5555 filled chip.

If you can't find anyone close I have no problem doing it.

Thanks for your help, bustedstr8. I'll consider your offer and maybe send you a couple chips to test, however that's not an option for every EPROM I write :)

From what I've read, this M27C160 chip works with having a bit more than 1 million of 16-bit sections, which are addressable individually. So, you enter a number, from 0 to 2^20-1, in binary form, on the A lines (pins 1-10 and 33-42), being 0 a voltage of 0 (or very near it) and 1 a voltage of about 5 (or close to it) and you get the bits that section (sector?) contains, on the D (Q) pins, which seem to be pins 14 to 30 on this EPROM model. Therefore, it seems my programmer is reading wrong always the 6th bit (starting from 0) on all the 16-bit sections it reads (it always read 0, no matter what). Am I getting this right? if so, maybe this thing is easily fixable...what do you guys think?

Thanks!!
 
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bustedstr8

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Yes, it looks like D6 is always stuck at 0.
I have no idea how easy it would be to fix. If 27c160 verifies on another machine, you will probably be fine burning them, just not reading them.
 
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aha2940

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Yes, it looks like D6 is always stuck at 0.
I have no idea how easy it would be to fix. If 27c160 verifies on another machine, you will probably be fine burning them, just not reading them.

Damn, this is a bummer. I had not in my plans that this programmer would break so soon. Funny that it works with smaller EPROMs, however it does not work with these 160s, and I just tested with an M27C322, same FFBF pattern. Chinese POS LOL. Just curious: can anybody please post a pic of their TOP3000 boards? I seem ho have found something funny on the bottom board of mine...

Thanks!!

P.S: Can anybody please recommend a programmer that will not break my bank but is trusty and good quality? just in case I have to replace this one completely.
 

purple

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On some eproms reading and writing voltages can be different, sometimes I get error when verifying but usually write is successful. Some 160 and 322 types need just a bit more than 12v, try different psu's and see if it does make difference also try not blank checking before you write. (maybe this makes them corrupt?)
 

mainman

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Damn, this is a bummer. I had not in my plans that this programmer would break so soon. Funny that it works with smaller EPROMs, however it does not work with these 160s, and I just tested with an M27C322, same FFBF pattern. Chinese POS LOL. Just curious: can anybody please post a pic of their TOP3000 boards? I seem ho have found something funny on the bottom board of mine...

Thanks!!

P.S: Can anybody please recommend a programmer that will not break my bank but is trusty and good quality? just in case I have to replace this one completely.

The only bullet proof programmer I can recommend is the chipmax2 but it will break your bank at $545 but it is well worth it if you use your programmer a lot, excellent quality.

Both the top and vp programmers are hit and miss, you go cheap and get what you pay for.
 

Fox1

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The only bullet proof programmer I can recommend is the chipmax2 but it will break your bank at $545 but it is well worth it if you use your programmer a lot, excellent quality.

Both the top and vp programmers are hit and miss, you go cheap and get what you pay for.

You can get a TopMax (Parallel port) for under $200 and it will do more than the Chipmax2. Of course, you need a parallel port hah
 

aha2940

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You can get a TopMax (Parallel port) for under $200 and it will do more than the Chipmax2. Of course, you need a parallel port hah

The parallel port is not an issue, I have an old laptop with parallel port (heck, it even has serial port!) dedicated for usage with the programmer. I'll research a bit about this.

Thanks!!
 

mainman

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You can get a TopMax (Parallel port) for under $200 and it will do more than the Chipmax2. Of course, you need a parallel port hah

Yeah but it's not a good idea to have a programmer that is locked to one machine, the fact that my programmer is locked to xp is the only reason I am updating it despite the fact it has served me faithfully for years and despite I still have multiple machines that run xp for legacy support.

That parallel programmer might seem like a good ideal now but it will show it limitations and age quickly to you.
 
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DNSDies

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I have a GQ-4X USB, and it serves me pretty well, unless I'm trying t burn Fujiotsu 29f033c TSOP packages, in which case it might take about 6 or 7 tries to get a burn to stick.
Aside from that, it handles EPROMs like a champ.

It's fairly cheap too, and works fine in Windows 7 x64
 

channelmaniac

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You can get a TopMax (Parallel port) for under $200 and it will do more than the Chipmax2. Of course, you need a parallel port hah

AND you will need Windows XP.

The eeTools parallel port programmers are not supported with PCI slot parallel cards or with USB to Parallel adapters. You have to have an on-motherboard parallel port.

I have 2 of the TopMax programmers and just sold my 3rd for $245 locally. That's the discount I would get from eeTools on trading it in towards a TopMax 2, which I'll be getting very soon. :)
 
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mainman

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AND you will need Windows XP.

The eeTools parallel port programmers are not supported with PCI slot parallel cards or with USB to Parallel adapters. You have to have an on-motherboard parallel port.

I have 2 of the TopMax programmers and just sold my 3rd for $245 locally. That's the discount I would get from eeTools on trading it in towards a TopMax 2, which I'll be getting very soon. :)

Holy, do you really need a $800 programmer channel. What is wrong with the chipmax2

Btw there is a remap work around to use legacy devices hardwired for old motherboards parallel port with pci cards but you would still be locked to xp.
 

Xavier

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Well then it sounds like your not selecting the right eprom or it's not selectable, your system/software isn't compatible with it or it's not getting enough power (in that order).

I know on mine (different then yours) there's some small one like the 2716 that the most common brand ones just won't work on my system.

Those Chinese erasers are weaksauce, just crank that timer all the way...it still won't erase half of them. Do it again half way to make sure most are erased or real quick check if they're erased then take out those ones and do the rest for half way. I think these things run on both 220/120v and at 120 it just give them enough juice to really do anything. I had big one for awhile something like a spectraline and it erased most everything in 5-7 minutes / held dozens of chips as well. The bulb burned out on it though and all the ones I could find cost more than I paid for the unit itself.

I always check erase, program and verify to make sure I have a trustworthy programming.
 

aha2940

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Well then it sounds like your not selecting the right eprom or it's not selectable, your system/software isn't compatible with it or it's not getting enough power (in that order).

I'm afraid I am selecting the right EPROM in the software (it is selectable), the software is made by the same people who made the programmer and it is getting power from the USB port + the external adapter. The eraser I have is chinese, but even EPROMs that were sold to me as new, show that same pattern. 1 or 2 chips, I doubt. I have tested so far 25 blank EPROMs, all show the same FFBF pattern. This thing is broken, it's not something I have made wrong. I'll get a new one when I can.

Thanks!!
 

Xian Xi

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Check the soldering to the socket on it. It could be a broken joint or something else.
 

The Webmiester

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I have a TOP3100 and a GQ-4X and I'm constantly switching between them for reading and writing different chips. For example, GQ-4X will not read old 2764, 27128 etc chips that I have. But then the TOP3100 won't write 27C040s well.

Have you tried manually setting the address and reading the bits? Put the chip on a breadboard, power it (no program power), set the address to 0, set the mode to 16-bit, and read off the data bits to see if your D6 bit is being written.

There's also always a chance that the D6 pin in the programmer isn't great, maybe try something like only inserting the chip half way.

Lastly, I know the GQ-4X has a mode where you can test each pin on the programmer, like turn them on and off and measure with a meter. Maybe the TOP programmer software has that too, I can't remember off the top of my head.
 
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