Programmer for TMS2516

[Eheran]

Those are TSM2516 EPROMs from almost 30 years ago, see here for more details:
https://www.eevblog.com/forum/repair/mettler-fp80-broken/

[edavid]

Sorry, I didn't see the other thread.

I'm not sure why you thought the EPROMs were the cause of the original problem.  If properly programmed, EPROMs are very reliable.

Do you see any difference in behavior with the EPROMs vs the copies you made?

[Eheran]

It was suggested that they lose data.
No difference with the error, still mostly "A/D conversion error (overflow)".

[stj]

why dont you just buy an old professional programmer from the 80's off ebay??

i have a micromaster1000 that does every eprom from 2716 to 27c040 AND pals & gals & bproms & 8bit mcu's.
much simpler than buying usb junk.

[helius]

why dont you just buy an old professional programmer from the 80's off ebay??

i have a micromaster1000 that does every eprom from 2716 to 27c040 AND pals & gals & bproms & 8bit mcu's.
much simpler than buying usb junk.

I tend to agree, but that also requires that you have a working computer with a parallel port, unless you find one of the higher-end programmers with serial comms (which were primarily products of Data I/O or Stag).

[stj]

you just reminded me that i also have an ELAN wih serial interface.

[Kjelt]

why dont you just buy an old professional programmer from the 80's off ebay??

That is something I did and cost still a lot of money (four times more than a new chinese 866 programmer) but the problem is that you only do that if you have more old equipment you want to service or that is your interest.
For the OP this is his only apparatus that was broken and he wanted a cheap and fast way to do it, then a new programmer that supports the chip is the best advice IMO, otherwise you could get stuck in more problems (old Windows version 95 or XP, old pc with par.port etc. etc.) than necessary for the job at hand.

[Eheran]

Correct. Just replacing them with EEPROMs costs a lot less and 0 problems are to be expected.
Buying a old programmer could cause who knows how many problems.

And there is another point: Nobody told me about another programmer that can do the job. Even if it would be much better... i need to know about it first 

[helius]

you just reminded me that i also have an ELAN wih serial interface.

Now there's a beauty, with support for 110 and 134.5 baud, and RCA COSMAC!
http://matthieu.benoit.free.fr/elan_E2A_editing_programmer.htm

[stj]

mine is a 5000 gang programmer, not an E2A

anyway, if the guy just needs one set of devices for one project/repair, it would be simpler to just ask on the forum for someone in the same country to program the devices for them. 

[janoc]

So im going with a TL866 programmer and XLS2816AP-250 2kx8 EEPROM like this one, correct?
They seem to be pin-compatible with the TMS2516 except for pin 18 and 20 (CE and OE).

I have checked the sw for my TL866 and it certainly lists generic Intel 2716 as supported, also the TMS2716 variant. At least reading should certainly be possible, but I have no way to test as I don't have any of these chips on hand.

The software allows selecting the programming voltage up to 21V. Not sure whether that is good enough or not for your chip - it doesn't appear to be able to do 25V.

[stj]

another option is to find some 27c16's

pretty rare, but cmos & pin compatable with 12.5v vpp

[Eheran]

Well, the new EEPROMs work just fine. But i dont know wether the data in the old EPROMs is corrupted form dataloss. The company doesnt seem to send me that data, making that a a dead end for me... i can try to troubleshoot the hardware* all i want, if the ROMs are corrupt im not getting anywhere.
So how likely is a dataloss after 30 years?


OT: Too bad i cant programm... i would build a Arduino based version to manage the data. So absorption/transmission of light in 3 points and 2 Pt100 sensors + powering a heating element, transmission gets higher when the substance melts -> meltingpoint.
*I have no clue where to start. How would i detect a defective A/D converter? They all get some input and give some sort of output... but is it correct? I dont know.

[Kjelt]

So how likely is a dataloss after 30 years?

Are you sure it is from 1986? My guess is that device is probably older than 30 years, the 2532's were already available in 1979.
The problem with eproms is that there was no data retention tests and guarantees back then. So from my own experience I have seen 2708s still ok from 1977 but also failed 2732's from devices from the 80's (game machines) So it all depends on lifetime, temperature (hot device environment), leakage of the unique silicon die etc. etc. In theory only one capacitor that has a worse leakage then the rest could cause the software to fail the checksum.
So I personally advise people to backup and copy (reburn) their eproms from before the 1990's within 20 years.

[Eheran]

Lots of other chips are from 1985 and some 1984. The EPROMs themselfe are 49. week 1984.

[edavid]

So how likely is a dataloss after 30 years?

Highly unlikely.  EPROMs in ceramic packages are usually the most reliable parts in the product.

*I have no clue where to start. How would i detect a defective A/D converter? They all get some input and give some sort of output... but is it correct? I dont know.

It's more likely to be the circuitry around the ADC.

[Eheran]

Aha... so the original information about EPROMs losing data and causing the trouble might be false?

What should i look at around the ADC? How would i see any anomalys? Sorry for these questions, my understanding of electronics is simply not high enough.

[helius]

Aha... so the original information about EPROMs losing data and causing the trouble might be false?

The structure of an EPROM is similar to SLC flash, with data stored by charge trapped on a floating gate. Over time, charge carriers tunnel out of the gate making the stored data weaker. Data retention is not infinite.

[edavid]

Aha... so the original information about EPROMs losing data and causing the trouble might be false?

I think so.

What should i look at around the ADC? How would i see any anomalys? Sorry for these questions, my understanding of electronics is simply not high enough.

Do you have the ADC datasheet?

[edavid]

The structure of an EPROM is similar to SLC flash, with data stored by charge trapped on a floating gate. Over time, charge carriers tunnel out of the gate making the stored data weaker. Data retention is not infinite.

Of course not, but under normal conditions it is > 100 years.

[wraper]

The structure of an EPROM is similar to SLC flash, with data stored by charge trapped on a floating gate. Over time, charge carriers tunnel out of the gate making the stored data weaker. Data retention is not infinite.

Of course not, but under normal conditions it is > 100 years.

If you are lucky, that is according to accelerated tests, and not every type. Many have ~20 year spec. EPROM corruption is not very common but isn't rare either. Don't know about this particular type but some obsolete types of those times now start t loosing their data like plague.

[Kjelt]

Of course not, but under normal conditions it is > 100 years.

I don't know your experience but I have encountered numerous eproms from end 70s begin 80s that failed.
Sometimes I could recover the original data by lowering the Vcc during reading.
100 years? Some new flash roms will not even survive that, don't forget that the silicon processes in the 70s were far less on quality and repeatability as they now are.

[Kjelt]

That said, in this particular case the eproms seem to be ok. So the problem lies somewhere else.

[edavid]

The structure of an EPROM is similar to SLC flash, with data stored by charge trapped on a floating gate. Over time, charge carriers tunnel out of the gate making the stored data weaker. Data retention is not infinite.

Of course not, but under normal conditions it is > 100 years.

If you are lucky, that is according to accelerated tests, and not every type. Many have ~20 year spec. EPROM corruption is not very common but isn't rare either. Don't know about this particular type but some obsolete types of those times now start t loosing their data like plague.

Whatever, I have yet to see a retention failure in a 2716, even for the ones I programmed myself 30+ years ago, without being very careful.

It's a moot point, since OP's repair theory doesn't really hold up.  If the EPROMs were good, copying wouldn't help, and if they had retention errors, copying also wouldn't help    The only way it would have worked was if the EPROMs read OK in the programmer, but not in the system.  I don't believe OP did any fooling around with the supply voltage while reading.

100 years? Some new flash roms will not even survive that, don't forget that the silicon processes in the 70s were far less on quality and repeatability as they now are.

Quality problems mostly lead to random failures, rather than data retention errors.

Older parts were actually specified in a much more conservative way, especially the programming algorithms.  When you only have 16K cells, you don't have to worry much about programming time, so you can overprogram the hell out of it.

That said, in this particular case the eproms seem to be ok. So the problem lies somewhere else.

I don't see where there's any evidence one way or the other, but I don't see EPROM failure as especially likely.  If the error message points to the ADC, surely that's the first place to look.

[Kjelt]

Older parts were actually specified in a much more conservative way, especially the programming algorithms.  When you only have 16K cells, you don't have to worry much about programming time, so you can overprogram the hell out of it.

True. Don't forget that these are eproms not mask roms , so they were actually designed to be erased and loose its charge , though due to uv radiation still there is not such a thing as a infinite isolation, there will always be some leakage. Also if the windows is not 100% shielded there is a chance on light leakage how minor even causing charge leakage.
Just google for vintage computer repair, pinball repair and video arcade games repair and you find many examples of the old eproms loosing their charge, still 40 years I think is extremely good and respectable and as you say a lot keep their charge over that period.