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Electronics => Repair => Topic started by: Ordinaryman1971 on April 08, 2019, 02:08:15 am

Title: How to program EPROM M2732 21V with TL866? SOLVED
Post by: Ordinaryman1971 on April 08, 2019, 02:08:15 am
I'm trying to program firmware for Keithley 195, one of the eproms is M2732 with programming voltage of 21V. I've read the eprom from a different meter without any problems but I have problem with coping it over.
And no, it's not bad eprom, I have about 20 of them, different makers but the TL866 goes up only to 18V.
What am I doing wrong here...
Title: Re: How to program EPROM M2732 21V with TL866?
Post by: wictor on April 08, 2019, 04:24:00 am
Hi,
Is that 18V measured during programming or is from some datasheet? TL866 is powered from USB port, so make sure you are using port that can deliver enough power. I have noticed that most PC ports fail doing that.

Wictor
Title: Re: How to program EPROM M2732 21V with TL866?
Post by: wictor on April 08, 2019, 04:28:19 am
Is yours TL866 old model or new plus model? The new one only goes to 18V and old one supports 21V.
Title: Re: How to program EPROM M2732 21V with TL866?
Post by: coromonadalix on April 08, 2019, 10:22:51 am
+1   i dont understand why they changed that voltage ... in the newest version.
Title: Re: How to program EPROM M2732 21V with TL866?
Post by: mc6800 on April 08, 2019, 11:05:41 am
I managed to program a 27C64 @18V with the TL866II (the datasheet says needs 21V), but only if I increased the duration to 1ms, from the default 100us. The same trick might work for the 2732.

The other option would be some sort of extra circuit to feed 21V to the Vpp pin of the 2732 once the TL866 voltage rose above say 15V.

Title: Re: How to program EPROM M2732 21V with TL866?
Post by: tsman on April 08, 2019, 11:15:19 am
Quote from: mc6800 on April 08, 2019, 11:05:41 am
I managed to program a 27C64 @18V with the TL866II (the datasheet says needs 21V), but only if I increased the duration to 1ms, from the default 100us. The same trick might work for the 2732.
I'd be concerned about long term reliability with that trick. It may be okay immediately after programming but you may get early bit rot.

Buying some 27C32s which only need 12.5V Vpp is the easiest option IMO.
Title: Re: How to program EPROM M2732 21V with TL866?
Post by: Ordinaryman1971 on April 08, 2019, 02:21:59 pm
I went to the maker website and it's correct, new model goes up only to 18V, I have only old version of those EPROMS so all I have are 21V.
Anybody wants to sell old version of the programmer... so I could have second one for this sole purpose, lol...
Title: Re: How to program EPROM M2732 21V with TL866? SOLVED
Post by: wictor on April 08, 2019, 02:25:36 pm
How about this: https://www.eevblog.com/forum/blog/eevblog-411-minipro-tl866-universal-programmer-review/650/
Title: Re: How to program EPROM M2732 21V with TL866? SOLVED
Post by: Ordinaryman1971 on April 08, 2019, 07:16:15 pm
I have new version of this programmer, the review is about the old version... which I'm willing to buy if there is anybody willing to sell, there is a voltage difference between those two, the old version will program up to 21V, the new version is limited to 18V.
So, basically I'm out of luck.
I have an older Willem programmer that I need to dig out and find a software for so I could maybe have it done this way...
Title: Re: How to program EPROM M2732 21V with TL866? SOLVED
Post by: wictor on April 08, 2019, 08:17:12 pm
My post was about the message #650 which shows how to use external voltage to rise max programming voltage. It is not programmer specific.
Title: Re: How to program EPROM M2732 21V with TL866? SOLVED
Post by: fzabkar on April 09, 2019, 07:11:37 am
21V = 18V + 3V lithium coil cell (or 2 x 1.5V alkaline cells)