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Issues burning 27C400 with Top3000... bad chips?

djsheep

djsheep

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Been having issues burning 27C400 with my Top3000.

I've tried Topall v9.xx which has a 27C400 profile in it and v8.xx which doesn't but have a profile, but I use MX27C4100 instead.

I've had two batches of 20 x 27C400 chips each.
Last batch 9 out of 20 chips burnt fine. 11 not burnable.
Latest batch of 20 chips, none burn, they all just the time out right when it starts with the message "Error at:0000 : (FF)"

Burner reads them after UV erasing as blank just fine.
Burner also reads the data from the 27C400 chips just fine.
Burning however...

Have tried various times of erasing.
Have tried using an external power supply.
Have tried multiple machines.

Ironically enough, the first batch of chips were painted over "refurbished" ones. This new lot are not painted and the real deal.

Just checking if anyone has any leads. I'm going to assume these are bad chips... but wanted to get some thoughts before I return this lot in the off chance they are ok.

I don't have another burner on me, so I can't do anything like that.

Thanks for any advice.
 
djsheep said:
Yep, all other chips burn with zero issues... done 800, 322, 080 recently. Once I hit the 400's though it's all bad news!
Click to expand...

Not sure about the real causee but started to have similar issue with my GQ4x4 programmer, and tried everything. Cleaned the pins, replaced caps, resoldered socket legs..

One thing did work for a while, is that i disactivated USB power saving in windows. That solved the issue for few days, with the same eproms that didnt work. But eventually the issue came back.
 
The thing is. Mine has done them before… even recently. I wonder if it’s just picky with the chips?
 
There’s three levels of delay to adjust, I’ve tried them all… but other chips have different settings it seems.

I’ll try them on a mates programmer. And if they work. I’ll grab a beefier programmer.
 
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djsheep said:
The thing is. Mine has done them before… even recently. I wonder if it’s just picky with the chips?
Click to expand...
I think its picky, on mine ST 27c160 programs fine.
Had some other brand 27c160's and none of them programmed on the Top
 
Same here with my TOP3000 [ first time was working , but after i did an update on programmer they dont programm these chips correctly (i know because i had some problems with them when i used them on Edward Randy conversion) , i use TL866-II Plus programmer to write them , i check also the VCC to be sure is writed with correct voltage witch in most of cases are 12.5V iirc ]
 
The only ones I ever got to work reliably in a top programmer are intel D27C400. They seem to be really expensive last I checked. Same story with most other brands as most folks here, otherwise.
 
AlxUnderBase said:
Same here with my TOP3000 [ first time was working , but after i did an update on programmer they dont programm these chips correctly (i know because i had some problems with them when i used them on Edward Randy conversion) , i use TL866-II Plus programmer to write them , i check also the VCC to be sure is writed with correct voltage witch in most of cases are 12.5V iirc ]
Click to expand...
Good intel. Perhaps an update to the programmer broke things? Is there any way to roll back to a previous version perhaps?

@skate323k137 - I saw in another thread you had luck burning these as 4096 with an adapter?

Sounds like a lot of folks had this particular chip burning at one point, but it’s stopped. Maybe Palpaltine executed Order 66 on 27C400’s.
 
djsheep said:
@skate323k137 - I saw in another thread you had luck burning these as 4096 with an adapter?
Click to expand...
Ah yes. That did work to some extent slightly better than using the mx27c4100 for a few brands. For a few chips using the right adapter as well as the 27c4096 programming profile did work.

Ultimately the intel D27C400 ICs programmed fine directly using mx27c4100 profile. When I could get those affordably, they were the go-to.
 
djsheep said:
Been having issues burning 27C400 with my Top3000.

I've tried Topall v9.xx which has a 27C400 profile in it and v8.xx which doesn't but have a profile, but I use MX27C4100 instead.

I've had two batches of 20 x 27C400 chips each.
Last batch 9 out of 20 chips burnt fine. 11 not burnable.
Latest batch of 20 chips, none burn, they all just the time out right when it starts with the message "Error at:0000 : (FF)"

Burner reads them after UV erasing as blank just fine.
Burner also reads the data from the 27C400 chips just fine.
Burning however...

Have tried various times of erasing.
Have tried using an external power supply.
Have tried multiple machines.

Ironically enough, the first batch of chips were painted over "refurbished" ones. This new lot are not painted and the real deal.

Just checking if anyone has any leads. I'm going to assume these are bad chips... but wanted to get some thoughts before I return this lot in the off chance they are ok.

I don't have another burner on me, so I can't do anything like that.

Thanks for any advice.
Click to expand...
The problem is simple: Cheap Chinese chip programmers don't raise the 5V supply line to 6.5v and a lot of EPROM brands do require this to program. For example older ST Micro EPROMs need 6.5V at the VCC rail during programming.

Keep in mind that this issue of raising 5V rail (VCC) to 6.5V is a different thing than the VPP (12v, 21v, 25v) voltage.
 
I’m guessing over time the programmer that used to work programming these chips then gets unreliable. Maybe a recap could help?
 
djsheep said:
I’m guessing over time the programmer that used to work programming these chips then gets unreliable. Maybe a recap could help?
Click to expand...
The external psu can help marginally

If it's still programming things like a 27c322 it's probably not the programmer beyond what we've all run into with this size IC.
 
Yah. No bueno with the PSU attached either.

Seems strange that there’s many reports people had no issues burning these chips previously, then all of a sudden it’s stopped working.

I’ve programmed using the same brand / speed I was previously successful with too. I might recap the programmer to see if there is any change.

322’s program just fine.
 
I just said the programmer does not supply what the EPROM requires to program properly.
Eproms that work with 5v rail:

NEC / Hitachi / newer ST chips with high density such as 27C800, 27C160 or 27C320/322

Eproms that won't work:
Almost everything else.

Why these programmers don't bump the 5v rail voltage? Because they aim mostly at flash memory chips and the circuitry to do that adds a lot to the cost...
 
l_oliveira said:
I just said the programmer does not supply what the EPROM requires to program properly.
Eproms that work with 5v rail:

NEC / Hitachi / newer ST chips with high density such as 27C800, 27C160 or 27C320/322

Eproms that won't work:
Almost everything else.

Why these programmers don't bump the 5v rail voltage? Because they aim mostly at flash memory chips and the circuitry to do that adds a lot to the cost...
Click to expand...
So the fact that I, and others, have previously burnt countless 27c400, and other chips not on your list with no issues was just a fluke?
 
Some of these use an 8 pin chip that does a buck/boost convert of the voltage to what is needed by the EPROM. A friend had a TOP2049 that had that chip fail and would do intermittent programming. Check that converter circuit.

Also, look in the window of the chips that do vs. do not work. Any difference you can see with your eyes? My TopMax won't do 27C160 chips that have 8 segments on the chip, but works fine for the ones with 4 segments. I use my TopMax 2 and it does both fine. It's a problem with the algorithms that was fixed on a later revision of software for my TopMax 2 that won't be getting back ported to the final version released for the older programmer I have so I have to just put up with it.
 
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